Here under follows the transcription of the chapter Leonardo of Houston Stewart Chamberlain's Immanuel Kant, published by John Lane, The Bodley Head, 1914.

Leonardo da Vinci

LEONARDO DA VINCI
Painted by himself
Drawn and engraved by Charles Townley

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The original text in German: Immanuel Kant
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See also the reviews of this book:
Kant in the 20th century. Review in the London Times Literary Supplement, 1914
Kritische Urteile über Chamberlain's Kant. Collection of reviews in german, 1909
 
 

VOLUME I page
INTRODUCTORY 3
GOETHE 13
LEONARDO 101
DESCARTES 197
BRUNO 311




VOLUME II
PLATO 3
KANT 169
NOTES 415
INDEX 513

99

LEONARDO

CONCEPTION AND PERCEPTION

WITH AN EXCURSUS UPON PHYSICAL OPTICS
AND THE DOCTRINE OF COLOUR

Our soul is composed of harmony,
and harmony is never bred save
in moments when the proportions
of objects are seen or heard.
Leonardo.

100

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101


LEONARDO
THAT Seeing is a passive as well as an active function is a maxim as old as Aristotle. But the difference between passivity and activity in different men repeats itself in the degree and the more delicate qualities of both. It must be our business to bring into relief those personal peculiarities of Kant's way of Seeing which differentiate him from other Seers. It is with this object in view that we resort to comparison. We desire ourselves to observe and See the most important of the Seers, in the profound conviction that this will carry us further and to greater advantage than if we were to go into abstract theories about them, and hedge in their doctrines with finely pointed fences of definition.
    From our first comparison, — that with Goethe, — we have won a significant and lasting advantage. The intellectual individuality of Kant revealed itself in striking contrast to that of Goethe. In Kant we saw a peculiar quality of intuition developed to an absolutely astounding degree. We saw the power of appreciating mentally that which has been described: and that which is described is something which has been brought to our minds parcel-wise, or, to use the technical expression, analytically: for it is only by degrees that words can present a Whole, whereas the Eye first gives us a Whole, and only by degrees separates it into Parts. Moreover, in Kant we found an important development of that method of perception which is projected from within to without, geometrically in accordance with formula, humanly

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speaking creative, — namely the mathematical method. In Goethe, on the contrary, we found as a characteristic the insatiable hunger of the Eye, and in connection therewith the impulse to treat even matters of theory as something actually seen. In spite of this, inasmuch as the Doctrine of Metamorphosis had furnished us with a clear demonstration of the relationship between passivity and activity in Goethe's manner of Seeing, we recognised its harmony with Kant's mental vision and his analytical distinction between Experience and Idea.
    To-day I wish to carry this comparison with Goethe further, for it still contains a whole store of instruction. I hope to convince you that without the help of Kant we could hardly succeed in correctly grasping Goethe's view of nature, while at the same time no other man leads us so directly and patently to Kant, as does Goethe. This consideration, then, will give you a twofold advantage. Still, I wish to associate with these two men a third, — another great artist. I hit upon my choice without any reference to chronology; — simply with the intention of avoiding the ever-present danger of allowing our lazy thoughts to crystallise, and of contenting ourselves with some idle phrase about the antagonism between art and philosophy. Unfortunately no lesser man than Schopenhauer has given encouragement to so stark a fallacy: he is the most read of all philosophers, and in so far justly as he is by a long way the most readable; pity, that among his many perversities of thought, (I can find no other word for them,) there should be the asseveration that “Genius and a head for mathematics“ should be contradictions. 1 It is not possible here to enter upon a refutation of this detestable asseveration, to which, in the very first place, the whole phenomenon of Hellenism would have to fall a sacrifice: it would be easy and entertaining to carry out such a refutation with no other help than that of Schopenhauer's own writings:

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but one feels almost ashamed to enter the lists against this much too clever man when one hears him in an important passage cite Alfieri as having been unable to master the fourth proposition of Euclid, and again bringing forward some unnamed French mathematician who, on reading through Racine's Iphigénie, shrugged his shoulders, and asked, “Qu'est-ce que cela prouve?“ 2 If those are arguments then one might, with equal force, come to the conclusion that because a certain nineteenth-century poet at the age of forty, and in spite of living in the country, did not yet know that tadpoles turn into frogs, therefore no Poet is gifted with the power of observing nature. The mischief of such phrases, when they are presented with the seductive eloquence of a Schopenhauer, is that they are scattered far and wide, and establish themselves as dogmas, and so it comes to pass that to-day we find many men who because, like Alfieri, they are incapable of something, pose as men of genius, and who, not content with the fact that “the pride of the human intellect,“ as Kant calls mathematics, is none of theirs, plume themselves upon their impotence. Nay more, these mental waifs who cannot even grasp the simple problem of the equilateral triangle, look down from the height of their superiority on the most important men if only they show any aptitude for mathematics, and catalogue them as second-rate goods. But we need not dwell upon this, though it is difficult to prevent our wrath from blazing up over the impertinence of so fundamentally perverted a dogma. It is time for us to enter at once upon the heart of our subject. 3
    Schopenhauer's thesis affects genius in general. Sometimes, however, he propounds it in a narrower and therefore more plausible form: in this sense he writes, “Experience has proved that men of great genius in art have no aptitude for mathematics.“ That is an important limitation, for even in his eyes it is not the

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artist alone who can lay claim to genius: indeed, he is fond of quoting himself as an example, and certainly he had no artistic sense. Nevertheless this contention, which is to be found in the thirty-sixth paragraph of the first volume of his principal work, is so fundamentally false, that one asks oneself how Schopenhauer could have been blind enough to let it stand unaltered from the year 1818 to the day of his death. If we only think of German artists, the very first that comes to our thoughts is the man who was so specially admired even by Goethe, the great, the only, I had almost said the holy, Albrecht Dürer. He is one of those great “men of genius in art“ of whom one can say that they were the beginning and the end and the culminating point, all in one. Of course historically they spring from what has gone before, and they lead to what is to follow after, but that association hangs about their noble forms like a mantle. Like the goddess from the sea-foam, the individual rises out of the mass, something new, something incomparable, that never was before, and never can be again. At the sight of such men we are struck by Schopenhauer's fine saying, “Art is everywhere triumphant.“ Perfection it is that blazes out upon us out of all the feverish struggles of these artists, — Peace that smiles upon us, full of trust, and resting from the hurry of the eternal strife for something higher. And where labour and thought and prayer have wrought together as tireless journeymen, there at last reigns Harmony, divinely restful, incapable of failure. Among these giants is Dürer — and mark this. Not only had he an aptitude for mathematics, but that aptitude was something quite out of the common. Dürer is the author of the first textbook of applied geometry in the German language! Besides that, he devoted a whole work to the hopelessly dry, and only mathematically interesting, subject of Fortification; and his lectures on the proportion of the human figure are a little miracle

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of intricate geometrical descriptions. In his partiality for mathematics, in his sure eye for the study, and the weight that he lays upon it for the educational equipment of the artist — as he writes, “mensuration is the right foundation of all painting“ 4 — we have the special characteristic of this great artist. This one example is enough to prove that Schopenhauer's contention that the great artist has no aptitude for mathematics is an untenable generalisation from single instances. Further, you will easily understand that I must have it at heart to refute the insinuation that Kant belonged to the class of inferior minds lacking genius, because he had a talent for mathematics: far rather do we see that the possession of that talent gives us no right to infer a lack of artistic feeling.
    Now, at last, I call up the man whose radiant name I should be loath to cloud with polemics — Leonardo da Vinci. No greater painter ever lived; and this great painter was like Dürer, and even more than Dürer, a pre-eminent mathematician and mechanician. At the same time — as we see every day more clearly — a man of an all-embracing intellect, a Seer who penetrated all that his eye saw, a Discoverer so inexhaustible that the world has perhaps never seen his like, a deep, bold Thinker. Let us compare his method of Seeing with the methods of Goethe and Kant: that, I hope, will save us from all future danger of the crystallisations of the phrase-mongers.
    Like Goethe, this man is all Eye. He calls the Eye the Window of the soul, finestra dell' anima, 5 whose precious qualities he is never weary of praising; the Eye is signore de' sensi, “Lord of the senses,“ 6 the Eye is the Source of all Knowledge. Those who rely solely on the study of learned writings, instead of becoming acquainted with the works of Nature by means of their own Eyes, are only grandchildren not Sons of Nature, that one

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teacher of all teachers. All Arts, all Sciences, all Thought, are according to Leonardo “daughters of the Eye,“ and so it is that the painter is nipote à Dio, “the grandson of God.“ The Eye of this remarkable man is nevertheless, like Goethe's, far from being an exclusively artistic organ, — it has also the power of penetrating the universe. A brilliant light radiates from his Eye — for it is the special characteristic of the Eye of such men that it not only takes up light as others do, but also sends out rays of light illuminating the darkness, glowing through the impenetrable until it becomes transparent. A ray of light radiates, I say, from Leonardo's Eye so brilliantly, that even the most prosaic historians must admit that in him the intuitive power of divination of this organ verges upon the fabulous. Leonardo anticipated our whole modern natural science, — that is to say so far as this was possible, relying upon the Eye alone and without the help of the higher mathematics, — which were not then known, — of the new instruments, and of the mass of observations which had to be mastered by whole generations. For example, this man who died in 1519, who had been brought up in the strict belief of the Church in a flat earth laid between Heaven and Hell, knew the principles of the Cosmic system as Copernicus developed them thirty years later. How he gained this knowledge, and in what connection it came to him, we know not. For his observations, up to the present time far from being all deciphered and published, are for the most part aphoristic, often forming an unsolvable tangle of the most various thoughts, jotted down in the midst of, or under, or across his sketches, or on the backs of his sheets of drawings — thoughts often occurring to him in the midst of his painting, which he evidently seizes in a hurry, in order to use them elsewhere. Sometimes he writes expressly, “This is how I must deal with the matter in my work,“ or something of the same sort: or they are

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clear and neat preparations for books which he seems never to have written, and it is only from the outline that we can make a guess at the direction of his thought. So in Leonardo's writings we find no astronomical system. Yet on one sheet, under a number of mathematical calculations, we find written in unusually large letters, il sole non si muove, “the sun does not move.“ Not another word. Here we have clearly a sudden inspiration. But Leonardo is no visionary: his was throughout a positive intellect, never weary of seeking the certezza delle scientie by the strictly empirical and mathematical road. Sperientia è commune madre di tutte le scientie e arti. “Experience is the common mother of all the arts and sciences,“ — and nissuna humana investigatione si po dimandare vera scientia, s'essa non passa per le matematiche dimostrationi, “no human investigation can lay claim to being true science, unless it can stand the test of mathematical demonstration.“ Experiment, therefore, and calculation must be brought into court as tests of the correctness of any assumed fact. In the same way on other sheets we find a succession of investigations and deductions all circling round this central idea of a stationary sun and an earth which is in motion. Take, for instance, the important recognition come la terra non è nel mezzo del cerchio del sole, ne nel mezzo del mondo, 7 “that the earth is not in the centre of the sun's orbit, nor in the centre of the universe.“ In this connection we over and over again find the remark that the sun is greater than the earth, together with the assertion that there are many stars that are many times bigger than the star which is the earth. Molte stelle vi sono che son moltissime volte maggiore che la stella che è la terra. 8 The recognition of the fact that the dark earth reflects light leads him to the further assumption that the light of the planets is also reflected light, and that our earth seen from the moon would have

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exactly the same appearance as that which the moon gives us. 9 From this recognition there was but one step to the affirmation that the earth must be nearly spherical in shape and revolve round its axis. Certainly, so far as I know, we possess no written proof that Leonardo in any of his abrupt sentences ever gave expression to the further fundamental thought of the heliocentric system; but a great portion of his work is as yet unpublished, and this idea of motion follows so necessarily from the tenets which I have cited, that we are compelled to accept the belief that it was known to him. If now we turn our attention from the movements of the constellations to the hidden inner movements of the body, we find that Leonardo with the help of a like magical power of vision suspected, and even had a clear idea of, the circulation of the blood. This has been denied on the ground that in one passage Leonardo compared the movements of the blood with the ebb and flow of the tide. But the objection breaks down, because the notes which we possess of Leonardo's thoughts date from the most various periods of his life, and nothing can blot out the words which we have in his own hand, in black and white, concerning il continuo corso che fa il sangue per le sue vene, “the continuous course of the blood racing through its veins,“ and over and above this that the blood which flows back to the heart, il sangue che torna indirieto, differs from that which, when the blood is driven out, closes the valves of the heart, che riserra le porte del core. 10 These words suffice to prove a deep insight into the mechanism of the circulation, which at that time was unsuspected and not discovered until a century later: for Leonardo knows that the blood “runs an uninterrupted course through the veins,“ he knows that it proceeds from the heart, and finds its way back to the heart, and he makes a distinction between the venous blood and the arterial blood. And here we must bear in mind that the most important

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works of Leonardo in this connection, as in others, are up to the present unpublished. They lie idle in the dust of libraries.
    I have chosen these two examples, the astronomical and the physiological, out of the great mass of material. Leonardo seems to have interested himself in every branch of science, and everywhere, through the mere penetrating power of his sight, coupled with the sagacity of his judgment, he appears to have forestalled science — often by centuries. Think only of his right appreciation of the significance of petrifactions and of the geological strata at a time when people used to explain the one as the playful products of a vis plastica, while for the other at best the Deluge was made responsible! But to my regret I can give no more time to this captivating subject. If you want more particulars I must refer you to the books upon Leonardo. 11 I must be content if, by quoting typical instances, I have made you familiar with the wonderful quality and astounding penetration of this power of perception. Words are insufficient, what we need is facts — and these facts patent to every man, even to the unlearned, point to an intellect whose kinship with that of Goethe is at once striking: the same ever-open Eye, never satiated, the Eye of the warder Lynceus (as he called it in my first lecture), surveying the whole world, and uninterruptedly entertaining the monarch imprisoned in the Tower with new pictures: at the same time it is an Eye which creates. Yet we are struck by two important differences. Leonardo sees more exactly than Goethe, his Eye is sharper, and he can do what Goethe never could: he can reproduce what he has seen so that it becomes something seen by others: he is a painter, and for that reason still further removed from Kant than Goethe. But just as the outer sense is more refined in Leonardo than in Goethe, so it is too in the case of that inner schematic power of perception, which Goethe hardly

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possessed, but which in Kant was conspicuously developed. In this respect the relationship is reversed: Leonardo is nearer to Kant than Goethe was; in mechanics, indeed, he is as richly gifted with genius as he is in Art. Take up the six beautiful volumes into which Ravaisson-Mollien has divided all Leonardo's manuscripts in the Bibliothèque de l'Institut, in facsimile and deciphered, and you will see that nine-tenths of these notes refer to mathematics and mechanics. Leonardo never ceased to calculate. His mind was busy with the squaring of the circle, and with groping attempts at infinitesimal calculation; from the flight of birds to the observation of a waterfall, in every direction the interest in mathematics and mechanics forces itself upon him side by side with that of the painter. In one place he speaks of mechanics as “a Paradise,“ and says of it, “the science of machinery or mechanics is the noblest of all the sciences“ — La scientia strumentale over machinale è nobilissima. On the sheet which contains perhaps the very first sketch for the Last Supper, we find immediately under the subject a geometrical problem drawn and solved in ciphers, and another sheet which contains studies for the Apostles and a pathetic sketch for the Christ, shows under these figures a plan for a piece of machinery with explanatory notes. So if Leonardo and Goethe are two men in whom, in contradistinction to Kant, the Eye is the organ of life, still two very different intellects must be looking out from this finestra dell' anima, two very different modes of activity, to quote Aristotle, and therefore at the same time two very different systems of philosophy. Starting from the outward and visible signs we shall reach the very core of the question if we pay attention to one thing, — that Goethe wished to paint and could not, whilst Leonardo presents such a culminating point of pictorial genius, that few can reach his level, none surpass him.

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    Goethe's lack of capability in the plastic arts would be less striking if we did not see him from childhood so passionately striving to attain mastery in this very direction. We know that as a student in Leipzig he painted more than he read. It was Oeser's studio, not the lecture-rooms of the juristic Faculty, that he haunted. And with what touching industry did he carry on this struggle for the impossible!
Doch unvermögend Streben, Nachgelalle,
Bracht' oft den Stift, den Pinsel bracht's zu Falle;
Auf neues Wagnis endlich blieb doch nur
Vom besten Wollen halb und halbe Spur.
In the end Goethe himself was bound to confess, “I was lacking in the true plastic power,“ and he adds the precious words of irony against himself, “my attempts at representing nature were more like distant suspicions of given forms, and my figures resembled the light vaporous beings in Dante's Purgatorio, shadowless themselves, and terror-stricken at the shadows of real bodies.“ What this defect meant Goethe accurately realised; for in a conversation with Eckermann he quotes with praise words of our Leonardo, — “If your son lacks the sense to make what he draws stand out in relief by powerful shadowing, so that one might grasp it in one's hand, then he has no talent.“ And do you know why Goethe had no talent for drawing? Why his copies were mere “distant suspicions of given forms“? Because he was deficient in the sense of Geometry. Because we men are so built that we are incapable of accurately grasping any form which nature presents to us, unless, consciously or unconsciously, we have held before it by way of comparison the complex network of possible forms which is innate in us, and have in this way assimilated that which is outside all rule, incalculable, and which has never existed, by contrasting it with that which is regular, calculated and for ever unalterable. This happens

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without our thinking of it during every second of our life: we are incessantly schematising. Later on you will learn from Kant to what degree our whole intellectual being is under the domination of Scheme. “This schematising of our understanding, when we are face to face with phenomena,“ he writes, “is an art hidden in the depths of the human soul.“ For the images which we receive from without, that is to say the complex of the impressions of our senses, cannot be grasped directly, but our intellect — the “activity“ of Aristotle — must first, as Kant says in a happy figure of speech, have impressed its monogram upon them. “It is only by means of the Scheme that images and conception can be brought into union.“ You see that from without to within there is an intermediary action similar to that which takes place from within to without. Our ideas, as you will remember from the metamorphosis, were only able to reach the Eye by borrowing a symbol, e.g. the leaf, from the world of the senses: but this world of the senses — so runs the new creed — can penetrate the thinking consciousness in no other way than by the intermediary of schemes of the understanding; and these schemes coincide with the perceptions with no more exactitude than the symbols coincided with the ideas. It is not my intention at this moment to weary you with metaphysical disquisitions; on the contrary, I wanted only to call your attention to the fact that the plastic artist shows us this secret domination of the “hidden art“ of schematisation in bright daylight, and so smooths the way for the understanding of one of the most difficult passages of Kant's Critique of the Doctrine of Perception. For the great painter, consciously and in the sight of all men, puts into concrete form that which in others exists in the unconscious “depths of the soul.“
    That is why Dürer wrote those words which perhaps may have struck you as strange a little while ago — “The

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art of mensuration is the true foundation of all painting,“ and the same order of thought gives rise to what he writes on the next page: “The outer (practical) work must be the indication of the inner understanding.“ And in order that you may realise how powerfully the geometrical and schematic principle is developed in so pre-eminent a modeller, and how busily it is at work, I would beg you to take up another work of Dürer's, “the four Books of human proportion,“ — not in a modern abbreviated edition, but in the original small folio of 1528, with all the charts and tables, as they left the master's hands. You will be astounded at the world of numbers and geometrical figures in which Dürer lived; they are enough to make you giddy. Indeed, every complication can be solved by figures, yielding of its own accord without any involving of the imagination: but one can hardly grasp how any man should have been able to carry in his head, as something visible, such complicated geometrical figures, as Dürer was obviously able to do. In the two first books the many charts of figures and the painful precision of the measurements will strike you as imposing. But now look at the third book! Here Dürer teaches us how we may at will change the fixed proportions; for instance, he takes a woman of average proportions that he has already shown us, and makes her first long and thin, then short and monstrously fat; or else he changes one part of the body, leaving the other parts as they were, etc., and all this he does without ever departing from the established foundations of geometrical schemes, and with the help of instruments which he calls “the perverter,“ “the falsifier,“ etc. The fourth book is almost more interesting: it shows “how you may distort the previously described images,“ and yet it is no simple doctrine of perspective in our sense of the word, but rather what mathematicians call the geometry of position, bound up with that of projection. You need

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only look at the figures on page Y4, Z, and those that follow, in order to arrive at the understanding of what Dürer expects of the art-disciple.
    Leonardo's brain was organised in like fashion. To be sure he was not so self-tormenting — for instance, look at his doctrine of perspective, how bright it seems by the side of Dürer's, — yet always and everywhere he paid respect to the mathematical relations, always bringing calculation into play, always displaying the geometrical Scheme between the Eye and the Object. One hundred
QuincunxQuincunx
and fifty years ago, Charles Bonnet, the Genevan botanist, introduced the so-called doctrine of Phyllotaxy, that is to say, the exact observation of the relative position of the leaves on the stalk.
    To the most widely spread form of this relative position he gave the name of Quincunx: in this the sixth leaf after the stalk has been twice encircled invariably stands immediately above the first; accordingly every cycle of leaves consists of five leaves. This discovery was the result of years of study by an experienced professed botanist. But two hundred and fifty years earlier Leonardo's artist-eye had observed the Quincunx, and

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Leonardo - Sketch of treehad drawn it with the most painful care, and that too in his Book on Painting. 12 You see with what mathematical precision the painter observed! and not only with precision but also with schematisation, for as a matter of fact this 2/5 position is only approximatively existent. But in order that you may also see the geometrician at work, I have copied here a little sketch out of Ravaisson-Mollien — (M.S. M. f. 78 overleaf). To this Leonardo has added the note “all twigs possess lines which work towards the central point of the tree.“ In order to understand him you must naturally only take into consideration the youngest twigs, and you must realise how this so-called central point year by year moves upwards, quickly at first, then slowly. Even so there is great boldness in such a schematisation. On other pages you will see how Leonardo was at pains to apply to the human head a similar law of relationship to the line of circumference. His comparative studies of various human heads, including monstrous deformities, are so well known that I need do no more than allude to them. *
    This cursory outline may suffice to show you what special qualities must be at work in a man who is capable of reproducing that which he has seen. Where these qualities are lacking there can be no painter, because there is no organ for the correct assimilation of form, and every attempt yields nothing but “distant suspicions.“ Of such men who are willing but incapable, Leonardo says, Multi sono gli uomini chi anno desiderio e amore al disegno ma non disposizione — “many are the men who

    * Leonardo drew a circle, by the help of which he fixed every point of the human head in a Scheme — nose, chin, ears, eyes, etc.

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have the wish to draw and who take delight in it, but who have not the capability“ — the disposizione lies in the aptitude for schematising. Naturally the geometrical quality by itself is not enough: yet it must not be wanting. The man who keeps the scheme steadily before his Eye, notes every deviation in the form, whereas on the other hand a Goethe, as we have seen, was rather inclined to underestimate points of difference, and in everything to see the points of union. “I was born in the school of identity,“ is his confession, but that is no school of painting. On the other hand, it is certainly interesting to discover that the thinker with closed eyes, whose stupendous schematic power of representation thought out the theory of the Heavens, showed in this respect a true intellectual relationship with a Dürer and a Leonardo. However much the science of mathematics may on one side root itself in logic, and signify in many of its adepts a purely abstract logical exercise of the intellect, — still the living water that gives nourishment to the tree is the power of the Eye, and so it may happen that a Kant may in certain respects stand in closer relationship to Leonardo than Goethe. In order to keep up the association of ideas in what I have to say, I shall return to this subject later, but I shall beg you once for all not to forget that the power of schematisation is a true formative power.
    In the meantime we must still linger awhile over the comparison between Leonardo and Goethe. I wish to show you how far-reaching is the difference that we have here observed in the Eye at work. For this purpose Leonardo's judgments on the essence of Art will be of service to us. According to him the senses are the true agents in real art, and the man who, like the poet, excites the conceptions of the senses by descriptions alone, makes use of a subordinate and indirect species of Art. Leonardo exclaims proudly, se'l pittore vol vedere bellezze

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che lo innamorino egli n'è signore di generarle. That the poet is equally master of producing beauty that shall be capable of exciting his love, that Leonardo denies. For il senso piu nobile is the Eye, and next to this noblest sense follows the Ear, la musica si deve chiamare sorella minore della pittura, whereas the artist in words is only indirectly and not really an artist, because he can only produce forms by roundabout ways, and by steering clear of the impressions of the senses: e per questo il poeta resta, inquanto alla figurazione delle cose corporee, molto indietro al pittore, e delle cose invisibili rimane indietro al musico, “the Poet in the representation of bodily things remains far behind the painter, and in that of invisible things, behind the musician.“ But the strongest objection that Leonardo has to make against the poet, is che non ha potestà in un medesimo tempo di dire diverse cose, “that he has not the power of saying several things at one and the same time“; but it must be the aim of Art to waken that Harmony of many tones which lies slumbering in the human soul, and that must take place with lightning rapidity, like an inspiration of the Deity: for armonia non s'ingenera se non in istanti, nei quali le proportionalità degli obietti si fan vedere, o'udire. “Harmony cannot be bred otherwise than in instants in which the relative proportions of things are seen or heard.“ Here, obviously, it is the plastic artist who is master, for he alone reveals his whole work in one single moment, and that is why Leonardo speaks of his art as a Divinity, una Deità. But the musician too gives in every moment a multiform perfect Harmony, while on the contrary the word-poet is forced to build up bit by bit, l'una parte nasce dall' altra successivamente, e non nasce la succedente, se l'antecedente non muore, “one part is born from the other in succession, and the following part is not born unless the previous part is dead.“ It is not my intention here to discuss the aesthetic doctrines of Leonardo: I

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have only felt compelled to show you with what a passionate bias this clear-sighted man paid respect to the Eye, and, beside the Eye, to the direct impressions of the senses in general as opposed to all mere reflection. The point of contact with Richard Wagner is clear, and in any other connection would give occasion to useful considerations.
    Here, however, we have one immediate and special interest — Leonardo, the man whose Eye at once reminded us of Goethe's Eye, is not only the antipodes of Goethe in respect to the scientific observation of Nature, but he comes very near to refusing altogether to recognise as true art that very art in which Goethe rendered immortal services. From the point of view which we are for the moment adopting, Goethe and Leonardo stand so far apart that we should hardly bring them into relationship, were it not for Kant who holds out the hand to both. For as a matter of fact, Kant, whom a while ago we found to be of so near kin to Leonardo that the two viewed from the distant Goethe appeared like brothers, now, seen from point of view of Leonardo's aesthetics, seems to move close up to Goethe. In this method of constructing “parcel-wise“ — una parte nasce dall' altra — we were able to discover a characteristic of Kant's method of perception; now it is Leonardo who shows us, that it is equally characteristic of every professor of the art of thinking, even of the Poet — and instinctively these words, una parte nasce dall' altra, call to our recollection Goethe's Doctrine of Metamorphosis. Of course Goethe examines nature with an Eye differing from that of Kant, yet he too is forced to construct, and in order to put the phenomena of nature perspicuously into form and to embody them in his memory, he cannot help allowing one part to arise from another. That is the exact purport of Metamorphosis. Practically there is, then, in Goethe's intellectual personality, exactly as in

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Kant's, a preponderant quality that we might well indicate with Kant as “understanding“ in contradistinction to “Sense,“ or perhaps still better as Reason (in the Kantian sense of “the whole higher power of recognition,“) in contradistinction to the power of observation. In both these men, Goethe and Kant, — however various may have been the sources at which they drew their impressions, — the insistence upon the idea of dallying with theory forms a common feature. However different from the path trodden by Kant may be that by which Goethe reached his Ideas, — he is only quite at borne, only quite the master, quite the creator, in that domain which Kant calls the Higher Power as opposed to a Lower Power; while Leonardo looks upon this so-called Lower Power as the Higher Power, and takes no account of any knowledge that has not, “born of the experience of the senses, made its way through mathematical exposition, and found its final conclusion in experiment.“ That is why he exhorts us to put no faith in authors who have wished by the force of imagination alone to make themselves interpreters between nature and man: non vi fidate degli autori che anno solo colla imaginatione voluto farsi interprete fra la natura all' uomo, and warns us not to give ourselves up to those things of which the human mind is incapable and which cannot be demonstrated by any natural example: Quelle cose di che la mente umana non è capace e non si possono dimostrare per nessuno esemplo naturale. As you see, Leonardo will only accept in relation to Nature the most strict empiricism knitting together effect and cause, whereas formation by Ideas as practised by Goethe, and defended by Kant, seemed to him to be idle imagination, or as he also called it bugiarda scientia, a science of lies.
    Here then we discover how far-reaching is the difference between Goethe and Leonardo; for it is not merely con-

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cerned with art alone, but extends to the whole method of contemplating nature. In the previous lecture we saw that Goethe was working with ideas when he believed himself to be in possession of experiences: that at once gives you an example of the dominant power of Reason — of the Higher Power of Recognition in contradistinction to empirical contemplation. For, as we saw in our investigation of the doctrine of metamorphosis, Ideas are certainly something seen, but not empirically seen; in other words, they are not given to us by mere experience. It is true that they are rooted in Impressions of the senses, though that is only the field which gives them nourishment: the air which surrounds them is that of Reason, and the daylight in which we see them, radiates from within out of a focus imaginarius.
    There is a saying of Kant's which will render us good service at this moment: for it describes exactly what it is that divides Goethe and Leonardo, and at the same time affords us a deep insight into Kant's own method of seeing; by abstract study we might perhaps have failed altogether in understanding his view; but in the light and shade of Leonardo's and Goethe's methods, his view stands out in plastic form. Kant is speaking of the essential nature of the Poet. After having, in diametrical opposition to Leonardo, assigned the highest of all artistic rank to the art of Poetry, he gives the poet the credit of encouraging “a free, personal and independent Power, untrammelled and unhampered, of observing and judging Nature as phenomenon, according to views which She herself affords neither to the senses nor to the understanding, and therefore to make use of her in the interests, and for the Schematisation of that which is transcendental“ (i.e. beyond the senses). The poet, then, teaches us to look upon Nature from points of view which direct experience does not offer us, and opens up in us a power to make use of what is clear to our Senses for the benefit

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of the schematisation of that which transcends them. This definition of the poet gives us an exact idea of Goethe's position in regard to Nature. In his method of observation there is a continual exchange between that with which the senses furnish us and that in which the experience of the senses only acts as a spring-board. Goethe is a good, trusty and, where necessary, a sober observer of Nature; in spite of which it is in the noblest sense of the word a poetical longing — I must add a yearning and a formative power — which impels him to observation: he wishes to put in practice that “free, personal and independent power,“ and unconsciously he flies far beyond the boundaries of empirical experience. His Orphische Urworte with its last line:

Ein Flügelschlag!  Und hinter uns Aeonen!

“One stroke of the wings! And behind us aeons!“ appeared first in the Morphologie of which the masterly Athroismos belongs to the osteology, and here in the midst of illustrations of bones and comparative tables he cries out:


Nimm vom Munde der Muse,
Dass du schauest, nicht schwärmst, die liebliche volle Gewissheit.

“Take from the mouth of the muse the sweet full certainty that thou art seeing and under no delusion.“ So it is the Muse that is to be our guardian goddess in the domain of the investigation of nature. Goethe, indeed, in certain moments is fully conscious of his own method of procedure; for in his legacy of notes upon natural science we find the following most noteworthy passage: “Phantasy is far nearer to nature than the senses: the latter are in nature, the former hovers over her. Phantasy can hold its own with nature, the senses are mastered by her.“ There you see at work the free, personal power, of which Kant spoke; at the same time you see the exact opposite of Leonardo's convictions and principles. For


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according to Leonardo all forms of knowledge are vain and full of errors, — vane e piene di errori, — unless they be created from the experience of the senses and tested by scientific experiment. Leonardo is such a strict empiric, that he goes so far as to warn the artist that he must know no other aim than to gareggiare colla natura, — literally “to compete with nature.“ How differently the Eyes of Goethe and Leonardo work we see not only in the Doctrines to which their method of Seeing gives occasion, but also in the success of their activity. Not only can Leonardo say of himself, “in painting I can stand comparison with any other man, be he who he may,“ 13 while Goethe, after toiling for years, is obliged to confess the contrary, but Leonardo's contributions to science are throughout of a different nature from those of Goethe. I am far from underrating Goethe's doctrine of metamorphosis, — his doctrine of colour, — his other scientific thoughts; rather am I deeply convinced that his whole method of observing Nature possesses for the culture of the human intellect a significance of which we are only just beginning to be aware. In many respects Goethe is even now hardly born. But this significance is one of culture and not of true science in the strict sense of the word. Goethe will teach us “to cast a free Eye upon the wide field of nature“ — a free Eye, that is to say the Eye of the conscious human creator, who no longer stands in dull obedience at the command of idle Matter, but who is able “to hold his own with Nature“: and that means at the same time the eye of the man who is no longer dazzled by his own compelling hallucinations, but who, thanks to Kant's efforts, has won together with his own freedom, the freedom of Nature. All this, — to which I propose to return to-day, so soon as our observations shall have ripened sufficiently, — we can perceive, and yet must admit that it was Goethe's part to excite and spur on exact natural science rather than really to

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further it himself: while Leonardo, on the contrary, who saw as a schematiser, and thought as a mechanician, was such a master of the art of gaining knowledge, that in his guesses he anticipated the triumphant course of our natural history. As Kant proclaimed to us, “experience alone is the fountain of truth in the observation of Nature.“ Leonardo knew that full well: gareggiare colla natura, “to compete with nature“ — that was his maxim not only in art, but also in science; it was his delight and the cause of his success. That the earth revolves is no symbolical idea, like Goethe's doctrine of metamorphosis, but a concrete theory; that the blood is chased from the heart through the veins, is not, like the discovery of the intermaxillary bone, an inference from an a priori admission, but a fact discovered by painstaking autopsy and observation. In respect of pure natural science, I think we may say that Leonardo surpassed Goethe almost as much as he did in painting. He knows the only true method: one sees that in him at once: and that says everything. Observation, experiment, mathematical calculation, — these are the three principles which he again and again impresses as the foundation of all knowledge. If beyond this we remember that he devoted a passionate interest to the technics of instruments (he built himself a sort of telescope for the observation of the moon a century before Galilei), we must admit that he possessed all the qualities which go to make the born investigator of Nature.
    By working up with more and more sharpness the contrast between Leonardo and Goethe, we have now reached the critical point, that is to say the point where we shall be rewarded if we sink a deep shaft, confident of coming upon a vein of the precious metal of discernment. Whoso thoroughly understands the difference between the value for science set upon mathematics by Leonardo and that set by Goethe, has gained much, not only in the

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estimate of the two great intellects, but for his own thought-life in general. At the same time this point is one of those which are of primary importance for the understanding of the intellect of Kant. For if a little while ago we saw Kant near — very near to Goethe — we see him quickly move back to Leonardo as soon as stress is laid not upon Art and Idea, but upon Science and Mathematics. Here it is not only the analogy of qualities between Leonardo and Kant which is dominant, — as it was just now in the case of the observation of schematising, — but a true close kinship in the whole manner of looking upon the universe. There, at a great distance, Goethe stands aloof.
    I have already spoken of Leonardo's love for mathematics; but I must still claim your patience for a few moments. Non mi legga chi non è matematico, “let no man read me who is not a mathematician“! Such forcible language as this should be enough! but we have still got to learn that in Leonardo this is no question of a mere predilection, nor even of an instrument indispensable to the practical artist, but the insight of a philosopher into the essence of the human intellect. “The man who undervalues mathematics nourishes himself upon confusion,“ says Leonardo, chi biasima la somma certezza della matematica, si pasce di confusione e mai porrà silentio alle contraditioni delle soffistiche scientie, colle quali s'inpara uno eterno gridore. “For truth and the power of knowledge are contained in the mathematical sciences.“ That is a very important saying, “the power of knowledge.“ Goethe would not have subscribed to it: Kant would have done so with both hands. And because practical knowledge is joined to the mathematical way of thinking, therefore Leonardo lays down the dogma that “no human investigation can lay claim to be considered as true science unless it will stand the test of mathematical demonstration.“ For the criterion of

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true science — vera scientia — is incontrovertible certainty, and knowledge in the sense of certainty is only afforded by mathematics. The consequence of this is that nessuna certezza è, dove non si puo applicare una delle scientie matematiche over che non sono unite con esse matematiche, — therefore no investigation can lay the foundation of true science, unless it can and does follow the path of mathematical exposition, that is Leonardo's impregnable conviction. It is with the clear recognition of the relationship between mathematics and knowledge that this miracle of a man forestalled Kant, in the same way that in his discoveries he anticipated Copernicus and Harvey. In one of his ripest works, Die Anfangsgründe der Naturwissenschaft, Kant writes in the same way, “I maintain that in every special nature-doctrine there will be found only so much exact science as it contains of mathematics.“ Certainly Kant, the thinker, analysed more exactly than Leonardo. The whole tenour of Kant's general philosophy teaches us to distinguish between “exact“ and “inexact“ science; he has shown us that a science which rests upon empirical observation alone, is only worthy of the name and dignity of a “science,“ so far as it does not deviate from experience, ordering its discovered facts systematically, and dissecting them in accordance with the relationship between cause and effect; but that such science should preferably be called systematic art (giving as an example the chemistry of his time), because the apodictic certainty of any true knowledge needs something more than empirical experience. This Something, which Kant calls the “Pure Part,“ is exactly that inner, human code of laws, which, in so far as it touches intuitive vision, is called mathematics. Nothing, with the single exception of mathematics, gives apodictic certainty, and apodictic certainty alone can be called knowledge in the strict sense of the word. Therefore, the more

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we have of mathematics, the more we have of exact Science.
    You see what a true and deep-reaching kinship exists between the methods of observation of these two men, who at first sight seemed so diametrically opposed to one another. Kant, absolutely devoid of all artistic gifts, has yet the power of recognising the fundamental significance of form and measurement in the building up of human knowledge; and in many of his works, and more especially in Die Metaphysischen Anfangsgründe der Naturwissenschaft, proves himself to be a genius of the first quality in the despotic domain of this schematic manner of Seeing; Leonardo, the artist, the painter of the Last Supper and the Mona Lisa, is none the less devoted to mathematics and mechanics; he compares the influence upon the intellect of their incontrovertible certainty, with that of light upon the Eye, and with the exaggeration of the hot-blooded artistic temperament, he utters the opinion that here alone lies the certainty of knowledge.
    We have to deal here with a true harmony between the dispositions of the two men. And as a matter of fact this harmony reveals itself exactly where Goethe misses fire — for we may legitimately here speak of a miss-fire as well in art as in philosophy. So far as art is concerned we may well overlook the position, inasmuch as Goethe himself bitterly felt his own failure. But in the matter of philosophy he was not so clearly conscious, and that is what has led us and him to a condition in which the pascersi di confusione has gained great force. That Goethe despised mathematics is of course the foolish twaddle of the titmice that chirp on every twig of life; a single sentence of his suffices to refute it: “no one can set a higher value on mathematics than I do, for mathematics afford precisely that which it has been denied to me to accomplish.“ 14 So he too felt that here something had

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been “denied to him,“ and how highly he often valued this “something denied“ is shown by a sentence in the Farbenlehre, the Doctrine of Colour, a passage where any irritation against the mathematicians might have been excused, and where in spite of that Goethe declares mathematics to be “one of the noblest organs of mankind.“ Still we must admit that Goethe was not only deficient in the power of practising mathematics, but was even unable fully to appreciate the essence of the science in its inevitable influence upon the human intellect. “It is a mistake to imagine,“ he exclaims pettishly, “that when I have discovered the mathematical equation for a phenomenon I know all about it that is worth knowing, and can consider the whole matter as sufficiently dealt with and to be laid on the shelf.“ 15 What does he mean? The function of mathematics is to apprehend, to prove according to the laws of motion, to reduce clearly to a science — just as Albrecht Dürer did for the outer form of the human body, and as Leonardo tried to do for the mechanism of the circulation of the blood in its inner parts. “The book of Nature is written in the language of mathematics,“ says Galilei. Goethe, on the other hand, finds a contradiction between the phenomenon observed and the mathematical scheme. For this sentiment he has to thank the pure power of his sight; but instead of allowing himself to be taught by Kant that if Image and Scheme do not exactly tally, it is due to the essential quality of the human intellect; 16 instead of recognising with Leonardo the fact that mathematical representation is the necessary organ of everything which can be called Science in the sense of exact knowledge, and that what he, Goethe, is striving after is not Science but something different, that is to say a glorified Contemplation, — that World of the Eye of which we spoke in the previous lecture, — and that this World demands ideal exposition; instead of all this, Goethe obstinately

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works himself up into the unfortunate idea that there can be an unmathematical science, — that the employment of mathematics must be kept within bounds, and that they must be relegated to a narrow domain in the Study of Nature, etc. Science and art, — so he maintains, — have “fallen into pitiable error through the wrongful employment of mathematics.“ 17 When we remember that Goethe's unmathematical dicta, of which we could cite many, are chiefly in the department of optics, and when we consider what a famous advance mathematical optics have made since Goethe's time, and what a wide outlook upon comprehensive knowledge has been opened up in this very direction in our days by the work of Maxwell and Hertz; when we realise the present importance of spectral analysis to astronomy, chemistry, and physics; and then when we see Goethe ridiculing the spectrum as little more than a mere puerility of Newton's, we must feel that however much the great observer of nature and Poet may have the right to view Nature in his own fashion, he is yet lacking in the understanding of the mathematical method of exact science. And this is the more striking when we find in Leonardo, two hundred years before Newton, a few but astonishingly correct remarks about the colours of the spectrum, and when we think of Kant's high estimate of the undulation theory of Huyghens, we have then the experimental proof that if we follow Goethe in the path of science, we advance no further in the exact sciences, whereas by following the mathematical path, which he detested and which Kant looked upon as the only right way, we have advanced from one theoretical and practical attainment to another.
    What, then, is the essence of the mathematical method? That is a question which it is impossible for us here to shirk, otherwise we should neither understand correctly Leonardo's extreme way of viewing Nature, nor Goethe's,

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nor should we understand why Kant's philosophical critique enables him to do justice to both these antagonistic views. I shall try to answer the question at once in as few and as simple words as possible, leaning indeed upon Kant, but without making him responsible for my free and illustrative exposition; we shall deal more precisely with the matter in observations to be added hereafter.
    So soon as we thoughtfully, — I use the word “thoughtful“ in contradistinction to passive contemplation, — so soon as we thoughtfully approach Nature and construct that “unity of objects“ without which she would no longer be Nature but Chaos, every single conjunction, arrange it as we may, means Motion. Think only of the commonest perceptions of any Bodies that you please, which you, innocent of any attempt at philosophising, simply join together, thinking in contemplative consciousness, something in the same way as the herdsman watches his grazing herd. Either the objects are at rest, and then our mind must move in order to perceive them, whereby we arrive at Form, or our mind is at rest and the objects move before it and then we arrive at Number: in most cases the two sorts of conjunction will take place simultaneously; and as you see, whether we direct our observation to the proximity in space, or to the sequence in Time, Motion is always at the bottom of it. Motion, says Kant, is that which unites space and time, and motion conceived, that is to say grasped by Reason, is Mathematics. If we look at the still geometrical figures in our school-books, we sometimes think that here is the very emblem of rest; but in the next lecture we shall see how the great Descartes laid the foundation of the higher mathematics, when he taught us to set free into Motion every resting Form, whereby we attain a second gift, namely, the power to convert every species of Motion into a visible, permanent Form.

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    But just in the same way as these higher mathematics proceed from the union of Geometry and Arithmetic, so it is only by further, and, as closer observation shows, powerful conjunctions of space and time, that a really intelligible and logical Nature comes into existence for us, and it is from these conjunctions that we realise the ideas of the inter-relationship of various perceptions, — of the interchangeability of phenomena, — of causative cohesion. Thus, for example, the relationship between cause and effect signifies a twofold Motion in space and time. You will find that set forth with unsurpassable lucidity in the fourth paragraph of Schopenhauer's principal work, to which I refer you. 18 And with further investigation and thought you will understand how Kant arrives at the definition, “Matter is that which is movable,“ and at the assertion that space can only be filled by motion. And that you may not think that I am leading you on to the pin-points of the most abstract philosophy, but that, on the contrary, you may understand that I am dealing here with the concrete and necessary apprehension of Nature by human intelligence, I will call your attention to the fact that our modern physics, however antimetaphysical may be their attitude in their empirical delusion, learn to recognise Kant's standpoint as the only justifiable one, and that the little globules of atoms are only preserved as a deduction and a help for coarser intellects, whereas Lord Kelvin and other leading spirits among the mathematical physicists speak of “centres of energy,“ and by atoms understand gyrating motion. Lord Armstrong, * in his book Electric Movements in Air and Water, asserts that there is no ground for looking upon Matter as anything else but Motion. Even the hypothetical aether he rejects as super-

    * I purposely cite English investigators because no others, not even Italians and Frenchmen, are so far removed from the influence of German metaphysics.

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fluous, and is of opinion that “empty space would do just as well, if we only chose to conceive a continuity of interacting motions.“ 19
    I think that this sketch, slight as it is, will suffice to make you understand and accept Kant's apodictic assertion, “natural science is throughout a doctrine of Motion, either pure or applied.“
    But here comes in a second important consideration, not, like the first one, composed of physical elements, but purely philosophical. The highest code of this science of Motion is not perceived as a fact in Nature, but is rooted in the essence of Reason. It is we ourselves, we men, who have no other possibility of comprehending Matter, that is to say, when we aim at a comprehension of Nature which shall be logical, thoughtful, and capable of founding an apodictic certainty of knowledge; — it is we ourselves, I say, who are unable to comprehend Matter otherwise than as Motion, and for whom in consequence of this every vera scientia, every absolute certainty is bound to result in a doctrine of motion either pure or applied. The human understanding works out the analysis of Motion by its special gift of schematic experience which we call mathematics. It is by mathematics that the human intellect assimilates and digests that which is foreign to it and outside of its ken. Much is rejected, but what remains from that time forth becomes possessed of a humanly comprehensible form. That is what Kant means when he says, “the highest law of Nature must lie in ourselves, that is to say in our understanding.“ To put it rather roughly, but in a way suited to the present standpoint of our study, Nature gives the facts, the human understanding gives the laws. To formulate this let me once more bring forward words of Kant's, “the human understanding does not create its laws out of Nature, but imposes them upon her.“ At the first blush this remark will perhaps strike you as

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strongly paradoxical, but it will suffice for the present if you to a certain extent clearly grasp these two things: all exact Science, in the true and strict meaning of the word, resolves itself into a Doctrine of Motion. All Doctrine of Motion is mathematics, and so far human. To try to escape from a law of our true Being is nothing less than an attempt to creep out of our own skin. We may well therefore praise the acuteness of the great Leonardo, who had so rightly and energetically grasped the fundamental law of all exact investigation — in opposition to whom when a man comes forward, even should he be a Goethe, and exclaims, Friends! I will teach you a Science that shall be unmathematical, — then we recognise and acknowledge the fact that the great man is entangled in deep error. Indeed, the error is twofold, first inasmuch as his definition of Science cannot be called adequate, and secondly because he does not rightly grasp the essence of mathematics, and their law-giving function in reference to all that constitutes causal conjunction, and that means Nature as it exists in our thoughts.
    Quite another question is whether that which Goethe strove after, that is to say an unmathematical, and to that extent un-logical and therefore unscientific comprehension of Nature, is not, say what you will, entitled to a profound measure of justification. Here, too, is a question that we must not leave unanswered, for it is of weighty importance in the understanding of Kant. But in order to answer that question we must do as we did in our former lecture; we must undertake an excursus which will furnish us with the indispensable and self-evident material. If you were minded without any further preparation to plunge headlong into Kant's abstract-analytical method of thought, I suspect that it would be very difficult for you to bring a vivid understanding to bear upon his exegesis of an unmathematical

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conception of Nature, what he calls “Nature as exposition“ — whereas starting from Goethe you are at once in a position to understand Kant, and so will be able to delight in the unexampled profundity of the most powerful of all thinkers. We must then take heart and undertake an examination of the relationship between exact Mathematical Science, to which alone Leonardo assigned any value, and Goethe's comprehension of Nature. In the main this excursus will result in a comparison of physical optics and Goethe's doctrine of colour; there are, however, some general remarks with which we have to set out, and which will weave themselves into our exposition as it progresses.

 * * * * * *

    The difficulty which at the outset attaches to our task is the fact that Goethe himself was devoid of any theoretical consciousness of his own procedure, one might even say of his own aim. His own saying, “a man has never gained so much ground as when he does not know whither the way leads,“ is true of himself; for while he believed that he was doing no more than lending a hand in contemporary investigations of nature, he was in reality founding a new method. That is the naked truth, the unrecognised truth which seems to have foundered without leaving a trace, yet not for ever, in the noise and dust of the vulgar riot of our successful mechanical science. There are moments in the activities of great intellects where they render superlative services: that is when they do not quite understand themselves, when they enter the lists to do battle passionately for some impossible assertion, in spite of being gifted with a keener sight than their fellows, and with more consequential thought than their censors: for it is just here where they entangle themselves in a mass of contradictions, that they work like an unconscious natural force, paving


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the way for future knowledge: here the intellect collects itself into an avalanche ready to sweep clean all the tidy paths of human frivolity, or like a volcano bursts the too heavily weighted crust in which the idleness of tens of centuries has imprisoned the bright fiery element of the soul of man. Only consider Goethe, that noble man! Is it thinkable that he with his brilliant eyes should have looked in the light during a whole lifetime, and have seen nothing true? Yet, as I know that here I shall at once be tilting against unbelief and contradiction, I will quote the words of a pioneer in exact natural science, the admittedly greatest physiologist of the nineteenth century, Johannes Müller. He was what Louis Agassiz, Clerk Maxwell, and Heinrich Hertz (but with their exceptions a dwindling number of our famous natural investigators) were, a really lofty intellect of permanent importance. Here is what Müller says with reference to Goethe's essay on the skeletons of rodents, — “It is impossible to point to anything similar which comes up to this projection sketched from the centre of the organisation. Unless I am mistaken there lies in this outline the foreshadowing of a distant ideal of natural history.“ Remember these words “the foreshadowing of a distant ideal“! And Müller, the exact investigator of nature, prizes the awakening of this foreshadowing so highly, that on the next page he pronounces the judgment, that Goethe has “reached the greatest“ not only as artist, but also as investigator. 20 Here, too, is a judgment which should never be forgotten. For we moderns have grown up under the nourishing showers of pseudo-scientific platitudes; Rudolf Virchow alone dared forty years ago to take Goethe as investigator publicly under his protection, a weighty witness indeed, upon whose exactitude and unimaginativeness no man will cast a doubt, but who unfortunately was not competent altogether to lift the veil of misunderstanding: for to that end would

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have been required that philosophical training which Virchow abominated, so that his fine words raised a great storm of dust at the time, but soon died away leaving no influence behind them. 21
    In these days every tiny two-legged wheel in the great machine of science thinks himself justified in shrugging his shoulders over Goethe as an investigator of Nature. I happen to possess an autograph letter from one of these celebrities, who rates his professorial dignity at a height which entitles him to allow himself the following judgment of Goethe: “his conception of Nature is just what an easy-going aesthete and collector of curiosities might make up out of his walks abroad.“ This is the audacity of a man of middling capacity whom the schoolmaster's rod and the sting of hunger have raised by luck to the degree of Doctor of Philosophy, and finally up the three steps of the Professorial Chair! A man whose fame may perhaps live through two or three editions of our encyclopaedias, dares to speak in this way of the princely intellect of a Goethe, of that god-like Eye which for more than half a century never ceased in the thoughtful contemplation of Nature, of a man of whom a Johannes Müller could pronounce the opinion that as an investigator he “reached the greatest.“
    But enough of this. If I were to talk myself into a state of indignation over the intellectual decay resulting from the narrow empiricism of a tyrannical science which has fallen a prey to the overlearned Philistines, I should not readily come to an end. The reaction has already begun; there are good men and true of a younger generation at work on behalf of Goethe the investigator, and what is more important than the influence of these individuals is the fact that a universal necessity, a cultural need that cannot be put aside, is forcing us to enter upon the road which Goethe has pointed out to us as the “foreshadowing of a distant ideal,“ unless we

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wish to fall into crass barbarism. A leading spirit among the living antimetaphysical empirics, Ernst Mach, has disclosed what is the next thing to be annihilated, and if his object was to serve the ends of a purely mechanical barbarism he has not been far out: our languages! In the interest of “science“ they are to be abolished in order to make room for an abstract international language! 22 The ideal which floats before the learned professor is the Chinese system of writing, because, being entirely ideographic, it throws overboard all ballast of expression of the finer emotions. 23 After that grammar and history are to be “laid aside.“ Add to this the simplification of the Alphabet, and supplement it with algebraical formulae and chemical symbols, and you will have collected together all that Professor Mach deems essential in a language. He is not far out. A science which only concerns itself with abstract Ghosts, is at no single point in contact with life. Goethe's desire, by means of his doctrine of colour, parenthetically “to enrich language and so facilitate the communication of the higher conceptions among the friends of Nature,“ from this point of view must signify the ne plus ultra of folly. And when Mach, in conclusion, expresses the hopeful opinion that the English language is in a fair way to reach that ideal, we will not ignore the tiny grain of truth which has crept into this Hellish dream, worthy of one of Breughel's Witches'-sabbaths, and join the standard of those who hold no inheritance more sacred than that of their mother-tongue. The richer, the more illogical, the more incomprehensible a language, the better does it hold up the mirror to Nature. The men who have attempted to rob us of our language, have, so far as in them lay, robbed us of Nature; has not Lord Armstrong taught us that science needs no more than the assumption of empty space (vide supra)? In contradistinction to which the man whose genius was rooted

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in the sovereign and creative mastery of language, — in his much-despised teaching of nature followed the one object, to give us side by side with his immortal poems that which was their one eternal Source, visible, inexhaustible Nature with all the wealth of its many forms.
    Goethe, as I said before, did not possess a critically analytical consciousness of his new method, and hence it is that his judgment as to the relationship between his way of investigation and that of true science, is hazy and easily misleading.
    Sometimes his insight is clear enough, for example when he cites the attraction which in his youthful days Spinoza exercised over him, and adds, “the mathematical method was the very opposite of my poetical method of thought and exposition.“ This, of course, is a general statement; the mathematical method, dear to the Jewish Thinker, seems to Goethe to be in opposition to his own poetical method of thought. And yet when we come to deal with the special investigation of Nature there are passages of decisive import which may be brought into court. I select one from the year 1826, which possesses the importance of a composition with mathematics. Goethe writes, “It was not long before I was compelled, in deference to my own capabilities and relations, to claim the right to view, to investigate, and to comprehend Nature in her simplest, most secret beginnings as in her highest and most striking creations without the co-operation of mathematics. That has been my contention through life. Any service that I may have rendered in that way is open to all: how it may appeal to others remains to be seen.“ 24 Is not this perfectly clear? “In deference to my own capabilities“ — that points to the capabilities which are “in opposition to“ Mathematics. And Goethe claims the right to view, to investigate, and to comprehend Nature in accordance with these capabilities. To view, to investigate, to com-
 
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prehend, that is a perfect programme for a personal system of Natural Philosophy. Further on in the same disquisition Goethe says in so many words that “a new point of view justifies new opinions.“ This recognition explains the many passages in which Goethe declares, with no trace of bitterness, that his method of contemplating Nature “is incomprehensible to the Professors, for the simple reason that they think otherwise“; it is in these passages that he confesses in regard to the first great congresses of German works on natural history, that they furnished nothing which could in the slightest degree touch, or move, or excite him, no new encouragement, no new gift, — and this was the man who “for fifty years had been passionately devoted to the observation of nature“; for among the German natural scientists there was “not one that showed so much as the slightest approach to his own way of thinking.“ 25 And there are other passages which come under this category, in which Goethe in his last years, — as, for example, in the essay on the rodents quoted above — instead of as was his wont portraying his efforts in the domain of morphology in the bright colours of the successful investigators, all at once “feels most vividly that his honest endeavours in the observation of nature, were only presentiments and not pioneering.“ All this leaves nothing to be wished for in the way of clearness and true insight. In such moments Goethe is so fully conscious that he cannot see eye to eye with the men of true science, that he claims it as a right to dare to investigate in his own way, and admits that this way is something which continues to be incomprehensible to them, indeed that he is dealing with a “new standpoint,“ — with something in the future, — of which the significance remains half veiled even to himself.
    Physics simply do not recognise the fundamental ideas of Goethe's Doctrine of Colour. So from the stand-

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point of physics it is impossible to judge of this theory. Goethe starts precisely at the point where Physics leave off. It is evidence of a quite superficial appreciation of the matter when people go on talking of Goethe's relation to Newton and modern Physics, and at the same time take no thought of the fact, that these two are entirely different. 26
    Unfortunately it is Goethe himself who with the utmost impressiveness and vehemence has spoken about his so-called relations to Newton, and not to Newton alone, but to exact natural science in general. Did you remark in the above-quoted solemn declaration the five simple words, “without the co-operation of mathematics“? That is where the evil fountain of misunderstanding still continues to flow. It is not without the co-operation of mathematics, but in opposition to mathematics that Goethe observes, investigates, and comprehends Nature. The mathematical method and Goethe's method may run parallel to one another, but can never coalesce: no compromise between them is possible: they cannot at one time work together and at another time without one another.
    One instance will serve better than a hundred to show you how deeply this misunderstanding penetrated in Goethe's case. One month after that fundamental declaration in which the practised eye alone can detect the blemish of the “without co-operation,“ he says to Eckermann: “surely it is not the mathematicians who invented the metamorphosis of plants? I worked it out without mathematics, and the mathematicians have been forced to admit it.“ If these words are correctly reported, they are valid proof that we must trust to our own powers in order to see clearly in this matter; Goethe, the herald and founder, leaves us in the lurch as to the true understanding of his work. Mathematics and metamorphosis! This would have been the place to show that we are

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dealing with two dissimilar and irreconcilable subjects which nowhere come into contact with one another. The first lecture has shown you what was Goethe's idea of metamorphosis; we must admit that, like every human acceptation, it implies the conception of Motion; but instead of trusting itself like the sailor to the stream, it hovers like an eagle in the empyrean from which the living hurrying flood is at once Motion and Rest: Motion, so far as its law of existence is concerned, Rest as regards form. Mathematics (and in a wider sense all true science, inasmuch as it everywhere obeys the one impulse to be converted into mathematics) have no other power and function than the analysis of the condition of Becoming; * even that which is at rest they must set free into motion, otherwise they have no hold upon it. Goethe's efforts, on the contrary, do not tend towards analytical knowledge, but towards the most intensive contemplation, — “the world of the eye,“ the law of which is not Becoming, but Being. That accounts for the peculiar permeation of that which is simultaneous and that which is successive which has sometimes puzzled us, as indeed it puzzled Goethe himself. For while science, whose whole essence depends upon the understanding of cause and effect, recognises Being as an almost imaginary point between something which has been growing and something which is yet to be, the Eye, on the other hand, although not blind to successive alterations, can manifestly never perceive the condition of progression or process of “Becoming,“ otherwise than as locked up in a condition of Being. This will suffice for the moment to show the absurdity of Goethe's outcry against the mathematicians. How was any mathematician, as such, to discover Meta-

    * There is, so far as I can see, no single English word in common use which accurately conveys the meaning of the German Werden as opposed to Sein. Werden is the process of coming into Being — i.e. a transition state; Sein is Being — i.e. an accomplished fact. I shall translate Werden throughout the book as “Becoming,“ or “coming into being.“ — R.

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morphosis? He would have been a poor mathematician. Nor do the words, “I discovered this without mathematics,“ hit the nail on the head any better, though Goethe rarely fails us in that respect. And as regards the closing remark, “they have been forced to admit it,“ that is simply based upon error. Goethe's doctrine of metamorphosis has been as much repudiated by Science as were his anti-mathematical optics. It may be admitted that the repudiation was not so unanimous and immediate, but only because in the domain of Biology the complication is far greater, so that room is afforded for endless misunderstandings. But open any reliable contemporary book on botany, for instance, Julius Sachs' History of Botany (chapter 4), and you will find Goethe's doctrine of metamorphosis unconditionally refuted. Sachs shows how Goethe was continually wavering between fact and idea, and he reveals the mischief of which hangers-on laid the foundation during long years, while they, instead of turning to account the thought of metamorphosis “in the deeper sense of idealistic Philosophy,“ introduced it into exact science, which was impossible without “combining the highest abstractions with the most careless and rawest empiricism, and in a measure with quite false observations.“ The doctrine of metamorphosis has been quite as much a hindrance as a help to the science of the nineteenth century. That is the judgment of a scientist whose right to be heard cannot be called in question. You see how peculiarly connected it is with the words “they have been forced to admit it.“ But the great confusion which to this day has existed between Goethe's doctrine of metamorphosis and exact science, is due, as I said before, to the nature of the subject. All the sciences are striving towards mathematics; yet Biology, in contradistinction to Physics, is still far from having reached the mark. And here we must depend upon a schooling of the sense of sight, otherwise the subject will not be seen at

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all. We may observe, but we shall not take notice. That was why before Goethe's time comparative anatomy dragged out a miserable existence; men like Kaspar Friedrich Wolff died unknown. Goethe, with several others around him like Camper and Oken, was the first powerfully to excite the imagination, and so compelled it to take notice of what was seen. Here alone lies the significance for science of a doctrine of metamorphosis. The whole of Goethe's natural science might be called “an introduction to the art of seeing.“ Nor is that a small thing to say; for phantastic imaginings do not teach the art of seeing, but on the contrary lead to those false observations which Sachs blamed; on the other hand, there is a Something which Goethe by a happy inspiration called the “exact phantasy of the senses.“ 27 This phantasy is — as the word describes it — something felt by the senses, not abstract; it rests upon very accurate Seeing, and the unsurpassable exactness of many of Goethe's observations is attested by Müller and Helmholtz, by Virchow and Gegenbaur, by Sachs and Ferdinand Cohn; here, however, exact Phantasy must be allied to exact Seeing. Scientific hypotheses all pass away, but Goethe's Doctrine of Metamorphosis and Doctrine of Colour will never pass away: they stand as firmly as the facts which they mirror in Reason. Hence the importance of Goethe's ideas in Zoology and Botany. Science has used his thoughts as she uses the ophthalmoscope, in order to see into the depths, to discover facts; but, only as tools, not as an organ. It is true that the Doctors of the theory of evolution delight in tracing their pedigree to Goethe, but that is the innocence of the elderly child that would do better to search for an ancestry in Moses, Sanchoniathon, Thales, and Empedocles; venerable men who historically would render it better service, and are also more in sympathy with its intellectual culture.
     But in order exhaustively to lay bare the relationship

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between Goethe's conception of Nature by means of the “Phantasy of the senses“ and the mathematically exact Science of Nature, we must avail ourselves of a concrete example. For this Optics and the Doctrine of Colour must serve our purpose. Naturally it is not possible for me here to dive into the mysteries of optics, nor indeed would any man be able to give an exposition of Goethe's doctrine of colour with greater brevity than he did himself. That immortal work is all Perception and pure Perception; the least learned of men can study it paragraph by paragraph, and see step by step what Goethe saw. Here sight and understanding are identical. One would imagine that every man would lay hold upon it. And since Helmholtz, whom I may well quote here as the universally honoured representative of the mathematical anti-Goethe science, has expressly affirmed, “the experiments which Goethe cites in his Doctrine of Colour are accurately observed, and vividly described; as to their correctness there is no dispute,“ 28 no one who might wish to read this forbidden book need tremble for his scientific salvation. Exact, correct observations, which have moreover earned the praise of a genuine university professor as being vividly described, can certainly harm no man. But I know that it is all of no use; no human being can be induced to read the Doctrine of Colour. This glorious child of a demi-god is like a sleeping Brünnhilde waiting for the dawn of the new day which shall bring the hero to awaken her. We can therefore only deal with a few leading principles: that however will suffice to enable you to grasp the difference between “Nature as Mathematics“ and “Nature as Exposition,“ and never again to fall into doubt as to the right of the latter to assert its right to a place side by side with the former. In this connection Goethe, Leonardo, and Kant, each in his own special individuality, will arise before your eyes.

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    The first paragraph in Helmholtz's Optics consists of a definition of light, set forth as follows: “Light is looked upon by the majority of physicists as a peculiar form of motion of a hypothetical medium, the Light-aether; and we will accept this view of the undulation-theory which very fully accounts for all Phenomena.“ Here you have in a nutshell the whole method of mathematical-mechanical science. The storied words of the dying poet, “more light!“ are often cited in and out of season. What would our sensitive souls have said if Goethe had called out “more special motive-form of the hypothetical medium!“ Do not, however, believe that with this poor joke I wish to cast ridicule upon the optical definition; no less a man than René Descartes is responsible for the conception that light must be looked upon as Motion, and indeed as the motion of an invisible medium pervading the universe. It is the acceptation of this theory that has made optics the most perfect of all sciences: I only wished to call your attention to the fact that the first law of all science — if science is to be exact, — is the abolition of that which is visible, or if not in so many words of that which is visible, in any case the abolition of that which is practically seen, in favour of an abstract, mathematically available, altogether unfelt and schematic representation. In the same work (p. 268) Helmholtz actually reproaches Goethe with the fact that “in his studies in natural history he starts upon the principle of never abandoning the domain of that which is visible to the senses.“ From the point of view of science, then, it is a mistake to dwell upon that which is visible to the senses; for, as Helmholtz goes on to say, “Every physical exegesis must rise to the level of all those Forces which can naturally never be objects perceptible to the senses, but are only objects of the apprehensive understanding.“ These so-called Forces are purely creatures of the imagination: even the most sober anti-philosophical

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Science now admits that they only exist in our heads: and for that very reason they are unable to make use of the perception of the senses as such, but have to replace them by a sensibility of the imagination. 29 What is then seen is, as one of the greatest men of genius among the physicists, Heinrich Hertz, admits, a delusion from which it is impossible to exact “any conformity with things.“ 30 The very first step then leads from concrete perception to the abstract, and until that has been attained no Science is exact. To the unlearned, to the men of simple thoughts, Light would seem to be the most concrete of all perceivable things. And yet here you have a definition of Light which thrusts aside all perception; for looked at exactly it contains only two propositions, of which the one says “Light is Light-aether,“ an idea which reminds one of the “I am that I am“ of Jehovah, and must be dealt with by the logicians; while the second adds the assertion that “Light is motion.“ Now since the most cursory reflection has already sufficed to teach us that the conception of Nature as Motion is an irrefutable requisite of the human intellect, — that is to say that it is not a law of Nature but of our brain, — and inasmuch as Leonardo as a keen thinker even in his day recognised the justice of this principle, — it follows that the above definition is neither more nor less than an universal metaphysical postulate. Since then, as you know, certain leading Physicists have also declared against the hypothetical medium, the aether, as superfluous. In their minds Light is nothing but abstract motion in empty space.
    But now let us, please, read a little further in Helmholtz. We come to the Scheme. As Kant acutely remarked, “The subjective principle of Nature precedes the objective, the combination precedes that which is combined.“ That “which is complex must be supplied by ourselves,“ for we can investigate “only that which we

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Light-aetherhave ourselves supplied.“ Now in optics we supply a great deal. 31
    Following the advice of Helmholtz, let us attempt to represent the “peculiar form of motion of the hypothetical medium“ with the help of a wet thread which we shall hold in our fingers and allow to hang down freely, moving to and fro.
    Here you see the diagram; the line from A to B is the thread when not in motion; so the tiny particles of Light-aether follow one another in a straight line so long as they are not in motion: and here the dotted line shows you how the so-called waves behave as soon as a particle of aether begins to rock backwards and forwards at the top point A. And what is the reason of the movements of this same particle? Here again we have something peculiar. Helmholtz writes, “exactly as the movement of the single particles of the thread takes place, so would be the movement of a succession of aether-particles along which a ray of light should transmit itself.“ If then we have above received a definition of Light containing nothing more than the abstract admission that Light is motion, the Light-ray is at once introduced as an hypostasis transmitting itself along the particles of Light-aether, and so causing their motion. And whilst light is, according to the definition, a movement of waves, the Light-ray is, according to the mathematical definition, “a perpendicular line.“ Here we seem to have got into something like a witches' caldron! Let us just imagine that the sun is at noon: the world is steeped in light: how many rays are we to reckon there? Certainly more

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than you would see in the halo of a Byzantine Madonna's head. Does this raise a smile? And yet here is no joke, but your faith is bespoken for the following proposition: “we can in such cases consider the movement of the particles of aether inside a ray approximately as an isolated mechanical Whole, progressing independently of the movements of the neighbouring rays.“ You perceive that the rays are an altogether material conception. The possibility that innumerable rays running side by side do not take up the lateral movements of the aether-particles, so that for the very superabundance of light-rays there is no light, is a question which you must settle for yourselves, for to that Physics afford no answer. If we had the wave-movement alone, or the rectilinear movement alone (which latter movement laid the foundation of the whole optics of Newton who knew nothing of any wave-movement), then in that case our power of conception would at least possess a possible illusion; but to our mathematical Physics both conceptions are indispensable: Light is a rectilinear movement which does not spread itself like sound in all directions, and in spite of that Light is at the same time a wave, or undulatory movement. It is only by the conjunction of these two contradictory hypotheses that all phenomena can be exhaustively and mathematically reduced to a Scheme. The great mathematician d'Alembert calls attention to the fact that the so-called “cloudlessness“ of Mathematics really only holds good where they deal with the wholly Abstract, but that the richer the evidence of the senses to which you apply them, the darker become the conceptions upon which you base their operations. 32 You see here how true are his words. Mathematical Physics are practical, useful, infallible, grand, bewildering — I would gladly grant their right to all the laudatory Predicates in the Dictionary, — with one exception, clear. Whoever in agreement with d'Alembert searches

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into their foundations, will find them obscure. When Goethe wished to lay before a friend a few ideas concerning light he began by storming against the unhappy conception of the Rays. “There is absolutely no question of Rays, — they are an abstraction invented to explain the phenomenon in its greatest simplicity, an abstraction worked up, built upon, or rather piled up, until the whole matter at last became muddled into incomprehensibility.“ But let us leave the so-called Rays and return to our Waves, only following the exposition so far until we meet a practical conception clear to the senses, so as to justify the belief that we are floating down from the cloudy Olympus of hypothetical constructions, and are setting foot upon the solid ground of empirics.
    And here I would crave your attention: the time has come for us, as Kant taught us, “to supply the synthesis.“ In proportion as I move the thread more or less violently, so the serpentine line which it forms in the air will show greater or lesser curves; in the same way the aether-particles in the Light-aether, in proportion to the violence of their motion, will deviate more or less from their original position, — in other words, the Waves will be higher or lower: this variation in the height of the Waves is known as the Amplitude of Wave-motion. Besides the height of the Waves their length has to be taken into consideration. The distance between a1 and a2, from wave-crest to wave-crest, or from b1 to b2, from wave-valley to wave-valley, may vary in length: that is called the Wave-length. Thirdly, the movement of each aether-particle, which can be imagined as rocking to and fro, may take place with varying speed: that is called the Duration of oscillation. Pray hold fast to the conception that we must admit in these Waves a varying height, length, and duration of oscillation. And inasmuch as thought, as the saying goes, pays no duty, we may besides all this assume various directions of motion.

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Once more let us consider the wet thread. I can move my hand from right to left and from left to right, and then the single particles of the string which is curving into waves will also move rectilinearly to and fro; the same holds good with the aether-particles; in this case we say that the light is “rectilinearly polarised.“ But just as I move my hand rectilinearly from left to right, I might equally move it in a right line to and fro from front to back; I must therefore assume at least two directions of oscillation, and indeed might, if necessary, assume as many more as I please; in the simplest case we speak of two perpendicular directions of waves mutually polarised. Again, I might move my hand in a circle or in an ellipse. In that case the single particle of the string would, instead of a straight line, describe a circular line, or an elliptic line from one wave-crest to another, or from one wave-valley to the next: here too we must assume the same of the Light-aether particles; in the one case we speak of circular polarised light, in the other of elliptic polarised light. There are several other complications, but for our present purpose this is sufficient. We can therefore conceive waves of varying amplitude (that is to say height), waves of different length, waves of different duration of oscillation, waves rectilinearly polarised, perpendicularly polarised in opposition, circularly polarised, and elliptically polarised. But now I have to make a last and highest demand upon your imagination. Represent to yourselves all these differences with all their various prepositions as before, “with,“ “in,“ “upon,“ etc. — high waves and low waves, short and long, swift and slow in their oscillations, in endless gradations, pressing upon one another in all directions, — and in addition the aether-particles in various straight lines, and also working through each other in circles and ellipses: and then do you know what you have arrived at? Why, the Natural Light of the Physicists, as the

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sun, the candle, the match brings it into existence! This again is a serious matter. Cross-examine Helmholtz: he will furnish you with information. “Natural light,“ he writes, “is a uniform compound of all sorts of differently polarised Light,“ moreover, “it contains wave-features of an endless number of continually intermingling values of oscillatory duration.“
    It seems to me that we have fairly carried out Kant's behests as to ourselves supplying the synthesis. Yet I must here insert a remark. Nothing would be more unjustifiable than to ridicule this Scheme of the physicists, far rather would I with complete confidence vote with Kant that such intellectual constructions are “the pride of human reason.“ It is only by degrees that the monstrous complexity of the illusion established itself, as new phenomena, which it was necessary to incorporate in the one great Scheme, gradually became known, new ones have cropped up since Helmholtz's time: as for instance the Röntgen Rays, which compelled the conclusion that the oscillations do not only take place perpendicularly to the direction of transmission, but also parallel to it; that is to say as if we were not only to move our wet thread to and fro rectilinearly and in a circular line, but also from top to bottom and conversely from bottom to top, — not only therefore in the direction of floor and ceiling, but also in the direction of the room's walls. There will always be new additional matter coming to the front, until in the end the Scheme of Undulation will become useless by reason of its growing and alarming complication, and then some genius will enrich us with a new Image which will combine Light, radiating energy, chemical agency, electricity, magnetism, in one single practical scheme paving the way for new discoveries. The new theory is already at hand, widely developed, only lacking as yet a presentation as Image. 33 Enthusiastic admiration is the due of those men who like

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Democritus and Descartes and Kant endow the human brain with such schematic and creative illusions; and unquestionable recognition is the meed of those men of exact Science who, like Newton and Helmholtz, by their scorn of fatigue, their gift of observation, acuteness, power of sensitiveness, and talent, not only enrich the treasury of knowledge, — adding to the already existing thoughts of genius which they have inherited, — but also render to mankind services of imperishable value. One need only think of the ophthalmoscope! The depreciation of exact science, as we meet with it here and there in the works of various fanatics and obscurantists, makes one so indignant because it denies manifest demonstrable services which every lamp-cleaner can see even if he cannot understand them; whereas the depreciation of philosophy and art is pardonable where it is due to stupidity or faulty education. We must have no misunderstanding upon this point. The one thing against which I defend myself is this, that an invisible church served by a priesthood of narrow-minded, arrogant, and intolerant professors, who under the honourable title of “learned“ enjoy a quite unjustified respect, — since learning and power of judgment by no means of necessity go hand in hand 34 — that these enemies of nature, this tribe of fanatics should seize upon my understanding even in childhood, should annihilate its healthy power of observation, should hold in a scientific vice its healthy thought, and compel my belief in silly dogmas with a tyranny more cruel than the tribunal of the Inquisition. There is no need for me to believe in God: it matters little whether I am a morally strong, energetic, and free man: but if I refuse to believe in the hypothetical medium, the waves that are rays and the rays that are waves, in the amplitudes and oscillations and polarisations and such abominations, together with the descent of man from apes and of apes from jelly-fish, then I am outside

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the pale. Heinrich Hertz gives a striking example with reference to our modern Physics. A piece of iron lies upon the table. Why does this iron not fly into the air, or pierce the table in order to fall to the ground, or burst asunder into millions of atoms? Just as in the case of Light, physics here set out such innumerable so-called “forces,“ all of them busily at work dragging the piece of iron hither and thither, that a mathematician would have to work for weeks before he could give a scientifically plausible proof that the piece of iron is really lying peacefully upon the table. Hertz writes, “But the truth is that all powers are so compensated as against one another, that the whole arsenal of them comes to nothing: that in spite of a thousand causes of motion which are present, no motion takes place: that the iron just remains quiet. If we lay these conceptions before unprejudiced thinkers, who will believe us? Whom shall we convince that we are talking of something real and not of the hallucinations of an extravagant imagination? 35 “We may accept the power of imagination of science even though it becomes extravagant; but that we should sacrifice our independence, our reason, our phantasy nourished at the fountain of perception, and lay it upon the altar of this Goddess of Abstraction, — that is something that we must fight against with might and main before it is too late, before this scientific barbarism shall have plunged us into the darkness of night.
    But we had proposed to ourselves to follow the course of the exegesis of Physics until we should at last reach something real and tangible, and not a mere imaginary perception. And here on the very page where there is all this talk of waves and polarisations, a little lower down a well-known idea beams upon me. I see the word Colour! and what do I read? “the most striking peculiarity by which Light of varying oscillatory duration distinguishes itself is Colour.“ 36 The unprejudiced thinker to whom

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Heinrich Hertz appealed will at first, as it seems to me, be staggered by this. Colour is oscillatory duration? Yet there is no mistake; for here is the definition: “when every aether-particle in the motion of light always, over and over again, follows the same course at the same time and at the same speed, then the Light is called simple, monochromatic, or homogeneous.“ The unprejudiced thinker is more and more puzzled. He remembers that to the Physicist Light and Visibility have absolutely no common signification; in every ray of Natural Light the Physicist detects a great quantity of “Unseen Light“ — there is the ultra-violet and the infra-red (or ultra-red): it follows that every wave must have its colour, a colour which no human eye can see. What is colour outside of the circle of Red, Yellow, Green, Blue? What is an invisible Colour? Neither a perception nor a conception in any way possible. Besides this, Physics are compelled, as we have seen, to premise that there exists a boundless number of continually interchanging values of oscillatory duration: this claim, raised in a somewhat different form by Newton, who admitted an endless number of material light-corpuscules, cannot be denied by any one who is possessed of the elements of mathematical Physics; now the physicists reckon the number of oscillations in the deepest red at 400 billions in the second, and in the brightest violet at about 800 billions: according to the definition of the physicists, therefore, there must be within the visible spectrum some 400 billions of different colours. In truth, however, in theory as in practice, we can well do with the acceptation of four primitive colours, as Leonardo has shown in many passages; many people, Helmholtz among the number, have thought it sufficient to distinguish three colours. 37 Besides this there is no relationship between the accepted number of oscillations and the order of progression of the colours: the numbers rise by

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a hundred billions and you are still in the Red; on the other hand, a few beggarly billions, perhaps ten or twelve, suffice to lead you out of the loveliest green into the darkest blue. It is a still greater tax upon you that you should believe that Red and Violet, two colours that so imperceptibly merge into one another that no art can draw a line between them, are the extreme opposites of one another, the one called into being by the slowest of all oscillations, the other by the absolute fastest. Again, spectral analysis has taught us that flames which present exactly the same colour to the eye consist of rays which occupy a totally different place in the Spectrum, and must therefore, according to the Physicists, correspond with different numbers of oscillations. 38
    I might go on for half an hour upon this subject; for so soon as mathematical physics tread upon the domain of colours, we wade up to our mouths in the thick slime of impossibilities and irreconcilable contradictions. As, however, I am not prepared to go minutely into this matter, and as it is nevertheless my duty to convince you that it is no private opinion of my own which is forcing itself upon you, but that I am expounding undeniable facts, I should wish to recommend to you an excellent Kompendium der Physik, of which I made special use in my student days: it is comprehensive, clear, and strictly scientific. 39 In the first lines of page 536 you will find these words, “our eye distinguishes different colours, which originate in the fact that the number of oscillations which strike our eye in the same unit of time is different.“ Now does not that give the impression of a perfectly concrete, reliable fact? The Dogma, like the credo in the catechism, comes first. Then the honest author brings forward a whole string of considerations, which are certainly not meant as objections, for that Colours are oscillations is a Dogma — Cursed be he

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who would look upon the sacrosanct oscillations as a mere scheme for calculation! — but these very considerations compel the author to a confession which you will find on the last line of the same page, — “Hence the perception of colour must be looked upon as a purely physiological fact for which physics have no further explanation.“ Thus in the first line the physicists' explanation of our perception of colour is given in concise language, and in the last line comes the confession that physics can give no possible explanation of the fact of the sense of colour. If we are to bring the two assertions into harmony we must premise that the Physicist makes a distinction between colour and the perception of colour. If he is speaking of colour, the word means no more to him than an epithetum ornans for “duration of oscillation,“ there exists no interdependence between Colour and Eye, colour is an objective physical phenomenon; he talks quite calmly of rays which are sensitive to red, — not made sensitive by red — as if every wave-length wore its own livery; 40 but so soon as his Physics take the eye into consideration the whole artificial thought-phantom collapses. Light, the whole fabric of waves, of rays, and of polarisations, — all is well and good until it clashes with the human retina; but as for colour, there your hitherto all-powerful juggler must confess himself beaten: here is a sensation which his physics will not help him to explain, and now comes the physiologist whom he himself called in, and if the physiologist is like Johannes Müller, a true philosophical spirit, he will tell the physicist, “with the exception of the purely optical mathematical definitions upon the subject of elementary motions, your doctrines all rest upon the most obvious contradictions: Light is energy of the senses, and colour is an affection of the optic nerve.“ 41
    We need go no further. We have reached the core of the matter. If you had already studied Kant, a word

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would have sufficed, and you would be able to survey the whole lie of the land, as one looks down from a lofty mountain peak upon the structure of the country below. That is the point to which you must be led, and you must once more be guided to an understanding of Kant before you have had the opportunity of studying the philosopher himself.
    Stand at the windows of this room and look out! What do you see? The green of the meadows, the blue of Heaven, the yellow of the corn, the white of the snow mountains, and the grey of the clouds. All colour! The whole of your Seeing consists in a Seeing of Colours; the conception Light is an abstract one, it is a collective name for all Colours. For if you consider the sources of light, such as the sun, the stars, and the flames and lamps which we use for the production of Light, they are in reality generators of Colour. Light without colour would be a contradictio in adjecto. Indeed, there is no such thing in existence as a white light. If a source of light appears to us as white, it is only a question of relative brilliancy, or else it is owing to the absence of any object of comparison. The old-fashioned street lamps of oil appeared to be of a deep orange-red colour when the gas lamps were near them: gas flames are orange-coloured, incandescent lamps red, incandescent gaslight that seems so dazzlingly white is blue when seen near powerful arc lights. 42 Whatever the eye takes in is Colour: everywhere Colour. And even white and black, notwithstanding that the careful observer is obliged to consider them as something special which he cannot without further elucidation put into the same category with the other colours, and though optical analysis teaches us that no active light contains them, still will be regarded by every independent thinker, as something related to Colour — as something positive. White is just as much as black a privatione de colori; physically it is the result of

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every exact mixture of two antagonistic colours, for instance, of yellow and blue, or of red and green, because the one visual impression cancels the other. It is impossible for us even to think of anything absolutely devoid of Colour; it would simply become at once invisible. But I would not have you believe that I am trying to prove Light to be a mere cobweb of the brain. That would be nothing but sophistry. But in the same way as out of the experience of various tones I construct for myself the idea“ Sound,“ which thenceforth assumes consistency, and under which all the phenomena which the sense of hearing perceives may practically and theoretically be gathered together, so out of the experiences of my eye which one and all can never assume any other form than that of Colour, — because every affection of the nerves of the eye is Colour, — I abstract the universal conception of “Light,“ and if the expression “abstract“ should seem too strong, — remember I am developing no system, and am not weighing my words in a scale — we will substitute the word “derive“ — the conception of Light is a thought derived from the perceptions of Colours. Do not run away with the idea that these are hair-splittings; rather are we dealing with a real distinction, with a distinction which the slightest reflection makes clear, and once made clear, may of itself suffice to render impossible the eternal confusion between the mathematical optics of the Physicists and the doctrine of Colour of Goethe, which rests upon a close observation of the perceptions of our sight. Colours are a rock against which not even the force of a Hercules can prevail. We can neither add to nor detract anything from the conception of red and blue; and moreover they defy any attempt at definition. As Descartes says in his simple language: En vain nous définirions ce que c'est que le blanc pour le faire comprendre à celui qui ne verrait absolument rien, tandis que pour le connaître Il ne faut

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qu'ouvrir les yeux et voir du blanc. 43 The conception “Colour“ possesses no comprehensible element; it is, to speak physiologically, pure energy of the senses, and to speak philosophically it is a sensation and empirical perception. Light, on the contrary, is a matter of comprehension: in this case the understanding meditates upon material afforded to it by the senses, and for that reason the circle of this comprehension is uncertain and unstable: it even lies in our power to widen it or contract it. Under examination you would probably hold Light and Visibility to be the same, and Goethe's startling assertion that Light and the Eye are one and the same, 44 would at once charm you as a sound truth: yet, as you have seen, to Physics the conception of an invisible Light — therefore of a day that is night — is familiar, and science for the moment finds itself at a critical point where a new extension is gradually being acquired by this already widened conception, and not only invisible visibility, but Light which is not Light is accepted within the circle. For we are so far on the road towards comprehending in one united idea the phenomena of Light with those of electricity, of magnetism, and other molecular phenomena. This thought is not so new as the gentlemen of the Press, upon whom the modern world depends for its culture, imagine. You might almost say that it is seen as a germ in Plato's Timaios, and at any rate Descartes saw it floating before him, even though the phenomena of electricity were too little known in his time for him to entertain more than something like a general presentiment upon the subject. Herder, in the 2nd chapter of the 5th book of his Ideen, makes mystical allusions to the Identity of Light, Aether, the Warmth of Life, allusions which have no scientific value, but which show how near the same thought was to him. Kant, however, in an earlier writing (1763), says, “There are strong reasons for presuming that the expansion of

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bodies by warmth, Light, electric power, thunderstorms, perhaps also the power of magnetism, may be various manifestations of one and the same energetic matter which is distributed in all space, namely of the aether.“ 45 And in his last unfinished work, he had very accurately served as pioneer to the modern theory, by the hypothetical acceptation of his “material of Heat or Light,“ as a universal primitive movens. 46 This idea is one which it is no longer possible to lay aside, and if we then claim for Light that it is a “peculiar form of motion“ of the electric waves, or for Electricity that it is a “peculiar form of motion“ of the Light-aether, that is bonnet blanc, blanc bonnet, and is decided by practical considerations or arbitrarily. The conception Light is either so extended that visibility only becomes one phenomenon among many, or so contracted that Light itself only forms one special case inside a greater complex of molecular phenomena of movement. The various Colours, red, green, blue, yellow, orange, black, and white, on the contrary, remain what they have been from the beginning of time: on the one hand something entirely objective, a perception grasped by the understanding which no thought could have generated, but only the practical sensation caused by the object, — and at the same time entirely and utterly subjective in so far as Colour lies altogether in my eye, and is an expression of my purely personal relation to the object. Since then Light possesses the elasticity of all that is thought, Colour is an immovable phenomenon firmly wedged in between Object and Subject, coyly rejecting any arbitrary handling.
    You now know exactly why our exact science has had such noble successes in the investigation of Light, whereas its dealings with Colour have led to such a jumble of impossibilities and contradictions, that the world is puzzled and the specialists who have any literary scholar-

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ship begin to look up to Goethe as to a “Paradise Lost.“ 47 The conception Light is from the first derivative, inferential, the child of our human brain, torn away before its time from its mother, — the perception of the senses, — and so we may deal with it as may seem good to us. Not, be it noted, in the sense that would allow us to invent or to ignore experiences or to turn them upside down, but in the sense that we should guide our experiences from the outset on the road which they should follow in order to reach the arsenal of our Knowledge. That is the “supplying of synthesis“ of which Kant spoke. The changes with which the Scheme has from time to time to put up, are but adjustments to facts which cannot be forced into the chosen road. Thus Newton's idea of Light as motion differs from that of Descartes, — Huyghens', again, from that of Newton, — Young's from that of Huyghens; and here again we are brought face to face with deep-reaching changes. In this connection it is neither the most philosophical intellect nor the powerfully seeing Eye that will work with the greatest success, but the man who like Newton, gifted with the greatest aptitude for mathematical combination, possesses into the bargain the sure instinct for the practical adaptation of what he sees to that which is abstract and capable of calculation. John Locke long ago made the remark that Newton's greatness consisted in the discovery of intermediate ideas. 48 As an observer of nature, Newton is not worthy to loosen the latchet of Descartes' shoe. Descartes' inspired thought of the movement of a propagating medium was too lofty for him, he could not conceive of Light otherwise than as matter thrown out by luminous bodies; and his eye was so innocently unsophisticated that he felt compelled, two hundred years after Leonardo, to hold fast to the biblical number seven in relation to colours, and in his remarks about the colours of shadows, fell into blunders about contrasting colours and the like, which any decent student of Painting

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in Italy could have pointed out to him. And so his painting theory of emission with his doctrine of colour has gone the way of all manifest falsehood (not to say absurdity), and at the same time his whole conception of Light, including what was imagination and what was perception, tumbled to pieces. And then what remained? Why do we all honour Newton as an immortal investigator? In the first place there remained the calculations of one of the most marvellous masters of figures in the world's history, of an intellect specially incomparable in combinations; for Newton is an unerring teacher when he remains within his own mathematical domain, the domain of observation peculiar to the human understanding: all that lay to the right and to the left of these calculations, the thoughts which gave birth to them, the perceptions to the explanation of which they were directed, all might be false, but the calculations themselves were none the less correct. The next point is that Newton not only employed calculations which never can be upset, but that his intellect proved to be true in everything which might even indirectly be calculable, especially in the invention and ordering of experiments having for their aim the reference of phenomena to movements capable of analysis. For example, the phenomenon of Colours, as to which Leonardo had made such keen observations, had no meaning for him. Never would he, like Goethe, have been led on the path of science by the sight of an aquamarine landscape with a purple sky in the snow country: the great Colour-phenomena of nature, — the blue of Heaven, the green of the thicket, the white of the snow — are all emblems of rest: Newton hardly saw them. But, on the other hand, he did remark in his dealings with optical glasses, that if you press one glass surface against another phenomena of Colour arise. Here Colour stood in relationship to motion, and to a measurable manifestation

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of power: here Colour must be pressed into the service in order that it should give birth to mathematical Physics! In Newton we have to deal with a mode of sight which is practical and also at the same time intuitive, on account of which, even as a contradictory contrast, it may be placed in a parallel line with the method of seeing of the artistic genius. That is why Newton's calculations remained a great generative principle for future science; that is to say, what he created — not its theory, but its practical ideas, and that implies the setting out of a number of points of contact between the mechanism of human thought and the mechanism of nature, the inventive achievement of an abstract artist. This side of the Newtonian intellect, — and this alone, — it is to which the word “genius“ applies, for here we see intuition and a bold combination of elements lying far apart. This recognition of the incomparable importance of Newton has been expressed in poetry by Albrecht von Haller, the great investigator of Nature, when he says that he — “Find't die Natur im Werk und scheint sie selbst zu meistern“ — finds nature at work and seems himself to master her. 49 To master Nature! that is not only the goal, but also the method of exact science, which shrinks from no violence of thought! Thus, for example, Newton's theory of gravitation rests upon two directly irrational assumptions, empty space and forces working at a distance: * and it strides away over every observation of the senses, as we have just seen in the case of Colours: with this intent it builds for itself a kingdom, a kingdom of its own, in which observation of the senses has no place, which is at once quite abstract and quite practical.
    This contrast leads us at once to a clear view of what Goethe's natural investigation strove for: a kingdom of that which is purely seen and unconditionally true. The

    * Forces working at a distance: e.g. the moon acting upon the ocean.


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two methods are diametrically opposed to one another. They take up no challenge: there would be no need for them to fight, if it were not that passion is apt to take the place of insight: indeed, the one might consciously help on the other, which so far has only occurred involuntarily here and there; above all, it would be necessary that all men of culture should as clearly recognise the relation, as the relation itself is clear.
    But before applying all this to the understanding of Goethe, I must say one word more. For sufficient reasons I have in this lecture hitherto only incidentally alluded to Kant, yet as a matter of fact it is he who has been my guide: it is to him that you owe any intelligence that you may have gained. To show this more accurately would require a too minute enquiry into pure philosophy. Still, I should be loath to conclude this consideration of Exact Science without having, at least aphoristically, made two points, first to prove how correctly Kant grasped the essence of Science, and secondly how undeniably Science itself, insensibly and involuntarily, bears witness to the truth of his philosophy.
    From what I have already said you know how devoted Kant was to Science, subordinated to the exact method of mathematics; how entirely he was at one with Leonardo in the belief that that alone was vera scientia, and that nulla certezza was to be found except under its sovereign rule; you would therefore not suspect that he could possibly wish to degrade it. In one monumental sentence he gathers together all that we have been learning about it, and I should like you once for all to impress that sentence upon your memories, because in it he is laying down something that hardly any man knows, and yet which we all need to know. “Physics are the investigation of Nature, not by experience, but on behalf of experience.“ Here we have the essence and the value of exact science enunciated and defined. I take it that

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after what has gone before any commentary is superfluous. Your own knowledge now bears witness that Kant is right. But if the wisest heads amongst us are in doubt about it, if they go on confusing method and matter, if they imagine that it is by experience that they have laid it down as a law that colours are “a varying number of oscillations of aether,“ whereas all these putative oscillations are, lock, stock, and barrel, only a method “on behalf of experience,“ that is to say, a method invented to widen the domain of experience, but not a method for coming nearer to what is experienced by so much as an inch: — then there arises the lamentable confusion by which we are now surrounded, and by which that principle of our being, which may be described as the innocent, the feminine, the receptive, and the parturient principle, namely Perception, is cruelly imperilled.
    I will say no more about this at present. Even if Kant is here only speaking of Physics, you know that all science of necessity strives after Physics — and so this method of investigation, not “through“ but “on behalf of“ experience, forces its way even into those sciences which are still at pains to tear themselves away from the matter of experience. For example, the essence and value of Darwinism consists in the fact that this doctrine revealed a method on behalf of experience. Darwin, like Newton, did not see clearly, and still less did he think deeply; his, like Newton's, was a practical inventive intellect, utterly without reference to Nature, and that is why the success of his labours was an enormous addition to the matter of experience. 50 We shall return to this in a later lecture.
    And now one more word about the way in which the whole history of our exact sciences bears witness on behalf of Kant. We are indeed standing upon the highest peak of a metaphysical mountain; I wish to

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make just a tiny rift in the mist which shrouds every man who has not yet grasped the thought of Kant, I wish just to open out a little streak of the blue sky, and by way of commentary to bring into play not Abstraction, but the practical history of our sciences.
    Democritus, up to whose time the philosophers had regarded the original characteristics of matter as qualitative, looked upon the “Qualitative“ as being really quantitative. That was a bold stroke, but it was a bold stroke which made Science possible. It was from him that Newton took the two important conceptions of the Atoms and Empty Space. Once admit that everything must be Quantity, then, in order that it may have form everything must be Motion: hence these two suppositions. This method of investigating “on behalf of experience,“ is called the Mechanical Method. Inside the same frame another method stands in opposition to it, the Dynamic: this was founded by Descartes, preferred by Kant, introduced by Faraday into Physics in opposition to the Newtonian conceptions, and Heinrich Hertz was intending to establish it in extenso when he was snatched away by death. It is the method of the more profound thinkers among the investigators of the exact school, which makes havoc of the absurdities of the mechanistic views. In this dynamic method a space filled without a gap is presupposed in which not hypostasised forces acting in empty space, but displacements, are the cause of all motion, and since experience is insufficient to make the calculation correspond, invisible masses and unseen movements have been invented in aid. 51 Outside these two methods there is no possible mathematical interpretation of Nature. 52 The exclusive stress laid upon Motion is common to both. But what is it that motion presupposes? Time and Space, nothing else. Space for the “outer sense,“ Time for the “inner Sense.“ And yet there is a third presumption: for “in

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Space, taken as such, there is nothing movable,“ and “it is not Time itself that changes, but that which Time contains.“ In order then to be able to speak of Motion we require, outside of Space and Time, “the perception of a presence and of the succession, or consecutive ordering, of its rules, consequently of Experience.“ If then we follow up the history of our exact sciences, — whether we build upon Mechanism or Dynamism, — we discover that it is their principle to adopt a minimum in the matter of Experience. Time and Space, with Motion as third: for anything more they have no use. They remove from Experience everything which has no reference to Time and Space, and consequently cannot be brought into any relationship to Motion. The sense of the colour red, of the colour blue, is certainly Experience, but it is not the Experience of a “consecutive ordering.“ Blue is blue, blue is not red — and even if I construct for myself a scale of colour, it still hardly possesses a greater value than does the idea of the metamorphosis of the bones of the vertebrae. For this conception of colour and of the scale of colour has nothing to do with Space, and contains no imaginable relation to Time, and so affords not the slightest point for mathematics to lay hold on. The Physicist therefore starts not from Colour but from Light, and even that he only seizes hold of where it suits him. The mirroring of outlines, the refraction of images, e.g. when seen in water; that is his starting-point, and indeed because there are here angles, and therefore something capable of measurement and calculation. The so-called Dioptrics, or science of refraction, preceded the mathematical theory of colours by a century: Kepler founded it in 1604, Newton's experiments upon the “Colours of Light“ appeared in 1704. It then became a point to discover some relationship between refraction and colour. You can easily obtain a simple and correct idea of the nature of Newton's

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work with the prism in the interests of this discovery. If you construct a light-tight box, and make a hole in it with a fine needle, you will obtain on a photographic plate, if placed at the right distance, a beautifully sharp picture of the whole landscape. If in the same way you catch a so-called Ray of the Sun, then you will obtain a picture of the sun. But if you enter the camera obscura yourself, and draw this Ray through a prism, projecting the broken Light upon a screen, you will no longer see the picture, for it is ruined past recognition, but in its place you will see colours, and those colours will be in a fixed consecutive series. That this experiment does not carry us very deep into the essence of colour, as colour, is shown by what follows: you saw, just now, how lamentably the Physicist fails as soon as he reaches the point where colour really exists, that is to say, the Eye; but that troubles him little; for his principle is, as we have seen, to give a minimum of importance to experience: he does not work “through“ experience, but “on behalf of“ it: and now he has what he wants: the Colours at which he could in no other way arrive are brought into relative position in space fixed by law, that is to say into a geometrical consecutive progression, and that again means geometrical Motion; and so he can also measure and calculate. 53 “The mathematician,“ says Kant, “can enter upon his construction of a conception from any datum that he pleases, without thereby being under any obligation again to explain that datum.“ 54 Not only does the mathematician pay no attention to anything further, but he consciously and of his own free will pushes it aside, together with everything which makes Colour what it is: all that concerns him is Space, Time, and therein Motion: colour is for him a number of oscillations and nothing more; not indeed because he has in this fashion fathomed the depths of the matter, but because he lacks the power to move one step nearer

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to the true essence of anything, by means of scientific methods.
    Rather than follow Goethe in his indignation over all this, we will learn to look upon the methods and successes of the exact investigator as a testimony to the correctness of Kant's fundamental conceptions of the human intellect. Kant teaches us, as you heard in the previous lecture, that there are “two branches of human intelligence; namely, the senses and the understanding, by the first of which objects are given to us, while by the second they are thought.“ What our senses give us we call Perceptions. For to-day let us leave on one side the one branch — the understanding. Let us talk only of the senses, the source of our perceptions.
    Within the senses we must learn to distinguish between the two parts of which Perception is composed, for that is the foundation-stone of the Kantian building: in every perception of the senses one part is empirical, the other part pure. The Greek word empeiria means nothing more than experience, but our more refined analysis needs the word experience for a special meaning. We will therefore not rebel against the expression “empirical.“ The empirical part of Perception is then that which we receive by sensation; everything that you see, smell, hear, etc., is, — in so far as you take into account this impression only — empirical Perception. “The impressions of the senses give us the first occasion to bring about experience.“ But before you can perceive as object an object afforded by the senses you must add something which is equally Perception, though not empirical Perception, — that is to say, not an impression of the senses, not a feeling received from outside, but something which you yourself contribute as man, and which Kant calls Pure Perception in contradistinction to the other Perception. This pure Perception is the idea of space. As Kant says, “the conception of space is the

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form in which our senses perceive, and is innate in us before ever a concrete object has impressed our senses in any one particular direction.“ 55
    I do not wish to-day to embark upon metaphysical discussions: and so I lay hold upon a concrete argument. You are aware that Natural Science has been developing itself, unhappily, out of touch with Kant, — for the most part in violent opposition to all philosophy: even such a man as Helmholtz, who busied himself much with Kant, yet in many essential points utterly misunderstood him; 56 now I should like you to take up the work of one of the most rabid anti-metaphysicians of our day, yet a pre-eminent and trustworthy investigator; Mach's Analyse der Empfindungen (The Analysis of Sensations). Here you will find, p. 93 of the 2nd edition, 1900 (104 of the 4th), the assurance that the biological and psychological investigations of the nineteenth century have led to the conviction that “the perception of space is born with us.“ As we do not propose to go deeper into this subject, this testimony, which is above suspicion, may suffice; it comes from a quarter in which for a whole century men have been labouring to prove the contrary. Mach and the men of his intellectual school are certainly of a very different opinion from that of Kant: there are millipedes that crawl upon the ground and eagles that soar in the air; both have the right to live, and it would be foolish to exact that they should view the world from the same point of sight; yet the recognition acquired with painful honesty that “the perception of space is born with us,“ expresses the same fact as Kant's irrefutable metaphysical creed — “the conception of space is present as a form of our sense-perception,“ — and that means the conditional possibility of all experience — “before a real object has fixed itself upon our senses by perception.“ You must not fall into the absurd mistake of supposing that Kant meant that Space is not something

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really present; on the contrary, he calls it on that very account pure perception, because Space is the fundamental condition under which things in general “manifest themselves to us,“ and thus at the same time determines the root of all perception. Moreover, you must understand that this pure perception by itself would serve us little; for, says Kant, “the Material or Real which is to be seen in Space, necessarily presupposes perception, and independently of that perception, which exhibits the reality of something in space, can by no force of the imagination be invented and brought into existence.“ Indeed, Kant gives here a fine definition of sensation when he says, “it is that which describes a reality in Space.“ We are not then floating in the clouds, but are working on behalf of knowledge attainable by every thinking man, and without which he can rightly grasp neither Goethe's investigation of Nature nor exact Science in its essence — and what we recognise is that in everything that nature in such generous measure brings to our senses, we must, within the limits of sensitive perception, and without reckoning all that our understanding afterwards adds to it, distinguish between a “pure perception“ which constitutes form, and an “empirical perception“ which constitutes the matter of perception. We can apply the saying of Aristotle which I quoted at the beginning of the lecture: within the limits of the perception of the senses there is passivity and activity; the conception of space is an “activity“ of the human intellect, it is the condition upon which that which is perceived by sensation (and that is “passivity“) can be viewed.
    Now for the application of these considerations. Everything that is size, form, and quantity, manifestly belongs to the conception Space, and that means to the domain of pure perception, to the domain of form, to the domain of the necessary purely human condition

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of activity. Here arises the plain certainty of mathematics. There are people who cannot see red, others who cannot see blue; empirical perception, that is to say the capability of grasping sensations, differs in different individuals; but there is no man for whom the sum of the three angles of a triangle means more or less than two right angles. Again, I can in my mind construct a cone, that is to say perceive it, and out of this perception develop all its mathematical essentials, without ever having had a cone presented to my empirical perception: while, on the contrary, I could never invest the cone with a colour or a smell, unless they had been previously known to me by the perception of the senses. If then in my investigations of Nature I confine myself as far as may be to the pure side of perception with the utmost possible neglect of the empirical side, I shall be in the enjoyment of two great advantages. In the first place, I take into consideration only that which is absolutely certain and universally valid, — the Formal, as you have seen, in opposition to the Material; secondly, as I am, so far as possible, limiting myself to my own peculiar human domain, I am able on the basis of fewer experiments to hurry on to further experiments, just as I investigated the essentials of the cone (that is to say, its mathematical essentials) in my brain. Empirical perception, that is, the perception of the outer senses, brings me at every step something new, something that I never had seen before; whereas pure perception is despotically confined to sure and fixed ways. Every voyage of discovery, every net that is sunk in the depths of the ocean, brings to light new forms of life, forms never suspected, never anticipated: every year chemistry discovers new elements; with modern telescopes the number of the celestial problems has only been multiplied: on the other hand, Newton's calculations are to-day what they were yesterday, and ten thousand

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years hence they will be just as true: they are more firmly built than the Pyramids of Egypt; they lay down the tyrannical law of our own human intellect, the law from which we cannot escape, and with which we “master Nature.“ Here, therefore, in the domain of pure perception, mixed up as little as possible with empirical data, I can work on behalf of experience, and can give to the results of experiment a safe, incontrovertible expression. For “empirical perception is only possible with the help of the pure contemplation of space and time; what Geometry says of the former, therefore, holds good also, without any possibility of contradiction, of the latter.“ Here, and here only, we obtain a firm grip of the latter. That is the somma certezza della matematica which Leonardo so rightly saw and honoured as the ideal for all scientific investigation. While in other fields the attempts at exact research are subject to change, so that as Kant says “only fleeting steps are possible, of which time preserves not the slightest trace, in mathematics, on the contrary, its progress is along a high road which the most remote posterity will be able to tread with confidence.“ That is why exact science, — and to be exact is the strenuous endeavour of all science, — confines itself to Size, Quantity, Form, Motion: in its ultimate perfection it postulates empty Space and Quantity — nothing more (see page 131): so when you see that it cannot altogether brush away the qualities of which empirical contemplation tells the tale, as for instance Colour, it bends and forcibly changes them into Motion, true to the principle formulated by Kant, “everything that is real in the objects of the outer senses must be looked upon as Force in Motion.“
    In this little exegesis I have for simplicity's sake always made use of Kant in order to render intelligible the essence and progress of our exact Science: but now you need only invert the whole story, — you need only

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recall what I have said about physical optics, and you will understand how I was justified in maintaining the proposition that our science bears witness to the correctness of Kant's analysis of the human intellect. It is the proof derived from experience that he saw aright.
    I have spent so much time over Leonardo's goddess, exact science, — that I have hardly any time left for Goethe's unmathematical method of perception. Yet I must hold this to be but a small evil. For as soon as you have grasped the essence of exact Science, you almost automatically obtain as a result the essence of that observation of Nature which prefers the empirical method, the impression of the senses, while it as far as possible pushes on one side the so-called “pure method of perception“ as a mere formal principle, and only takes it into consideration where it touches the empirical and unites itself therewith, namely in the case of Form. “Quantity and mensuration in their nakedness,“ writes Goethe, “annihilate Form and banish the spirit of living contemplation.“ 57 Red is 400 billions of oscillations of the hypothetical light-aether in the second: we may well agree with Goethe in calling that a banishment of the spirit of living contemplation. It is in this spirit, in the spirit of living contemplation which has been banished by his opponents, that Goethe's observation of Nature is rooted. In order not to break through the circle, we will hold fast to his Doctrine of Colour.
    You remember how the physicist Helmholtz tackled the subject. First came an abstract definition of Light, then a rich mass of possible constructions of the “illusion,“ as Hertz calls it, finally came the question of Colour. Goethe on the contrary starts with Colour. “All Nature,“ he says, “reveals itself by Colour to the sense of the eye.“ 58 He declines to speak of the essence of Light: “no mortal will ever be able to explain the nature of Light; and even should any man be able so to

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do, he would find no one to understand him or his Light.“ More comprehensive still is the passage in the preface to the Farbenlehre (doctrine of colour). “For really it is a vain undertaking to pretend to express in words the essence of any thing. We perceive results, and an exhaustive history of these results might at the most embrace the essence of the thing. In vain we take pains to portray the character of a man: but show us his dealings and his deeds together, and a picture of the character will arise. Colours are the deeds of Light, its activities and passivities. In this sense we can hope from them to obtain disclosures about Light.“
    I would not add a syllable to this: the Master has in these few words said all. My one wish would be that you should make friends with that beautiful, precious work, and learn to see through Goethe's eyes.
    I should gladly have said a little more about the Doctrine of Colours, but it would lead us too far. Only one thing I must say. If a brilliant process of discovery has testified to the value of the mathematical method, equally a century of experiments has led to the result that Goethe, and Goethe alone, has correctly observed the phenomena of Colour. In the matter of the Doctrine of Colour, Johannes Müller is already out of date; Helmholtz, whom we have only just lost — out of date; Hering, who is still with us — out of date; 59 Goethe, on the contrary, as a younger professor has recently assured us, “comprises the foundations of the most modern opinions“; and that will hold good a thousand years hence. It is no part of Goethe's endeavour to find a theory, that is to say a mathematical formularisation. When his brother-in-law, Schlosser, asked him how far his Doctrine of Colour might agree with the hypothesis of oscillations, “I had unfortunately to confess that my method took no notice of the matter, but that the only object was to focus innumerable experiences, to set them in order, to

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discover their inter-relationship and their position as opposed to and as agreeing with one another, to make them generally comprehensible.“ 60 My further lectures will show that this position of Goethe's corresponds exactly with Plato's and Kant's critical method of the understanding of phenomena, in opposition to every childish attempt at their explanation. Goethe's Doctrine of Colour is the almost spotlessly clear reflection of empirical observations, and this is a more difficult undertaking, and needs more training than the use of mathematical instruments. The student in his very first term can make spectroscopical experiments — I know it from my own experience; but to have such a clear insight into Nature as Goethe had, that is a matter of genius and self-education. Goethe himself bore witness that he was “not gifted with keen sight“; Leonardo's eye, on the contrary, pierced like a dagger into the very heart of phenomena; but I think that our theoretical endeavours will have rewarded you by enabling you henceforth to distinguish between keen sight and clear sight: if we accurately consider the schematising of the plastic artist, with which we dealt at the beginning of this lecture, we shall find it to be under the domination of the same despotic spirit that rules the schematising of an exact investigation: that Goethe could not paint does not only originate from any deficiency, it may also be looked upon as the positive quality of a spotlessly clear sight. And it may well be that this most rare quality accounts for the fact that people have not even understood how to read Goethe. To this day you will find in every book about Goethe, whether it be the work of friend or foe, the assertion that Goethe taught the existence of three primitive colours, Red, Yellow, and Blue, and that he held green to be a mixed colour. Now if the book in question is under the influence of Helmholtz, you will be taught that Goethe was mistaken, and that the three

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primitive colours are Red, Green, and Violet: if the book is more modern, it will probably prove to you with ease, that the idea of three colours is nothing but an absurdity, since all phenomena of contrast show that colours run in pairs, and therefore that, as main ideas, we must in every case accept two, or four, or six, or some other even number of colours. Of these, as Leonardo was the first clearly to recognise, Red-Green on the one hand, Blue-Yellow on the other hand, are without a doubt to be accepted as primitive colours. To set up primitive colours, on the contrary, as Helmholtz did referring to Young, and at the same time to leave out Yellow and Blue, means a ne-plus-ultra of the art of combination devoid of all observation. 61 If you take Goethe himself in hand, you will be amazed to discover that it never occurred to him to teach the doctrine of three primitive colours. It is true that he asserts that painters and colour-makers start from three colours because out of them they can obtain all the others; 62 but he himself fixes no number as a general proposition, but only affirms that colour proceeds from two extreme starting-points; nearest to the light a colour arises which we call Yellow: another one nearest to darkness arises which we describe by the word Blue. 63 And so far as the culminating point of these two extremes, leading through Orange on the one side, through Violet on the other, is Red (the Zenith as Goethe calls it); 64 while the depression of these same extremes through Yellow-Green and Blue-Green, reaches a furthest point called Green (which Goethe calls the Nadir): — so far we may certainly talk of four primitive colours as Goethe sometimes does. We might therefore in Goethe's case speak of two or of four primitive colours, but never of three. But the truth is that in his view colour is a unity; that is why he once suggests that Red includes all other colours. 65 But colour might equally be considered as a duality, inasmuch as “there are only two quite pure

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colours,“ Yellow and Blue. 66 Here, as you will surely observe, the fundamental idea is form, not the conception of Numbers. And for that reason, unless I am mistaken, our most modern physiologists with their purely mechanical conception of colours are not so near to Goethe as they themselves fancy. It is true that their colour-cross


Red

Yellow

Blue

Green


has set us free from the silly colour triangle,


Red



Red



or



Yellow
Blue
Green
Violet

and every empirical truth here signifies an approach towards Goethe, but I am afraid that Goethe must still wait a while before he becomes quite modern. True, he has said that to understand his teaching “needs nothing more than clear vision and a healthy brain.“ At the same time he has expressly declared that his teaching “is harder to comprehend than Newton's.“ 67 Clear Vision is as good as non-existent among us; we had to wait for Goethe to teach us that.
    And so we arrive at the answer to the question which rendered this excursus necessary — whether what Goethe

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aimed at, in express opposition to Leonardo, namely an anti-mathematical, and so far illogical and unscientific, comprehension of Nature, was not profoundly justified? I hope that the question now presents itself to you in a quite different guise and stripped of all phrase-mongering. You have seen with your eyes the might, and at the same time the beggarly poverty, of the whole system of pure science. “The mathematician is master over Nature,“ says Kant rightly enough, but what does the master know of his slave? Nothing but the work with which he has entrusted him. Goethe faces nature in a quite different spirit, and therefore with a different intellectual conception. His is not the ambition to master Nature, but to possess her intimately: she is not to work for him, but he for her; he wishes to re-create her and so make her his own. Exactly as we just now recognised Colour as something at the same time quite subjective and quite objective, so he paves the way for a view of Nature that shall be quite Human (without which it would be incomprehensible), and at the same time Pure Nature, or perhaps it were better to say as nearly Pure Nature as possible. Mathematical Physics are, as you have seen, something painfully abstract: for whilst, as far as may be practicable, it pushes on one side empirical observation, it not only denudes things of their essential nature, but it robs me as man of all the direct perceptions of the senses. There remain nothing but ghosts flitting hither and thither between object and subject. That Red can be understood as 400 billions of oscillations in the second is a most important formula for science, and therefore for practice: for life it is absolutely without significance. La meccanica è il paradiso was no conviction of Goethe's; he said, “mechanical formulae change the living into the dead.“ 68 His wish was to teach men to look upon life as something living.
    Here again there must be Method, otherwise there

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would be no unity and no goal to attain. The saying about phantasy which I quoted at page 121 — that it is very near to Nature and is the offspring of Nature — gives you the key. The relationship with Art is patent and sure, comforting and inspiring. But never forget that other saying about the “exact phantasy of the senses,“ do not forget that Goethe saw with incomparably greater accuracy than Newton and Helmholtz. We are not dealing here with creatures of fancy, but with that which Goethe calls “the productive power of imagination.“ 69 Without imagination we men are lost: only think of the waves and the rays, and the polarisation of the hypothetical medium! But while mathematical science works with Schemes which have only been invented in the interest of the human brain, Goethe is striving to come on the track of Nature, and by the means of Symbols to discover and explain, not her mechanism, but her Ideas. On one occasion his language is as clear as daylight, — “my impulse is the embodiment of Ideas.“
    As soon as we have obtained a clear notion of Goethe's goal and method, we understand what Kant means when he demands of us that “we shall judge phenomena not only as belonging to Nature in her purposeless mechanism, but also to analogy with Art.“ But before speaking in this connection of Kant who in such a peculiar fashion goes hand in hand with Leonardo and Goethe, it will fit our purpose to sum up briefly the result at which we have arrived in regard to the two ways of contemplating Nature. The riskiness of such an undertaking is well known to you, but this is not the case of a building in which we purpose to abide, but only of a milestone on the road towards the attainment of a living idea of the personal way of thinking of Immanuel Kant.
    There is one mode of Seeing, analytical, aiming at a mathematical dissection of Motions, — and there is another

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mode which is intuitive and directed towards an imaginary reproduction of Nature. Neither has any value unless it is exact. The material, both objective and subjective, is in both cases the same; but the direction of sight implies as condition a deeply reaching difference; one man is unable to see the one end of the spectrum, another man cannot see the other end: that accounts for Goethe's inability to understand the essence of mathematics, — while it equally accounts for Leonardo's one-sided preference for mathematical interpretations.
    The analysis of motions leads to true exact Science. The principle of Science is the lordship of the human intellect, which imposes its law upon Nature empirically perceived. The organs of Science are Mathematics for that which is seen, the Logic of cause and effect for synthesis outside that which is seen. 70 All matter of perception that cannot be assigned to one or other of these Schemes is put aside and ignored. We may therefore describe Science as systematic Anthropomorphism. From this there result two deductions. Inasmuch as the Anthropos himself is a portion of nature, it is manifestly probable that he will be able to assimilate an important part of the phenomena of Nature according to the scheme which is specially his own; to this the history of science bears witness. What he has assimilated according to this method is unconditional Knowledge: it is available at all times and to all men. This knowledge is not the same as reality: it is only a Scheme; it hardly touches the essence of things; yet it suffices for theory and for practice. That we should call the first deduction. And now for the second. On such a foundation it is possible to construct a flawless consistent building as a system of Nature, without the human intellect ever falling into contradiction with itself, without therefore any injury to the principle of thought, — correct logical sequence — and it is in spite of that possible that from
 
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beginning to end, at every single stage, it may only have grasped a fragment of the truth. For the revelation of this fallacy which gives the lie to the whole essence of the world — (we might call it the error ex incomperto) — science affords no handle. A Goethe is therefore fully justified in demanding that Nature should be considered as not only mechanically logical, but also according to another method; he is only wrong when he calls this other method of observation “exact Science.“ 71
    The essence of the other form of seeing is more difficult to define, just because it is a purer method of seeing. Here the characteristic feature is devotion to Nature, the struggle to escape from the serfdom of anthropomorphism. The Principle is Love, the Aim “the contemplation of Nature's own thoughts,“ the Organ the senses in partnership with Phantasy. That which is thought is here incapable of being known; as the Indian sage Bartrihari says, “there are no words for this thought.“ Think only of the doctrine of Metamorphosis: the doctrine of colour runs on all fours with it. Yet we must always keep before our eyes what is the meaning of our so-called knowledge, and within what narrow bounds it is fixed; rightly viewed, as we have seen, the knowledge of our Science is rather a method of investigating and mastering Nature than true knowledge. By science, our powers, the physical conditions of our existence, our arsenal of the material of knowledge, are enriched. But it is only its subjective acceptation, and the elaboration into something personal, that enriches our intellect. And this is the way that Goethe adopts. Of his doctrine of colour he himself confesses that it cannot be taught, “it must be held as practical, not as theory.“
    Let me here make my own profession of faith. You know how greatly devoted I am to exact science; that is above any other the sphere in which, had the fates been kind, I might have been in a position to render

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some service. At the same time I am firmly convinced, that the greater the prosperity of the development of exact science, the more indispensable must become a purely contemplative conception of Nature, — and that moreover in the interest of human culture. And if we wish to define this method of contemplation from the standpoint of Leonardo, that is to say from the standpoint of a strictly and logically synthetic understanding, then we must say that it is a contemplation of Nature that is devoid of causality. Pure contemplation tells us nothing of the past, nothing of the future, nothing of cause and effect. “The tracing back of effect to cause is a mere historical proceeding,“ says Goethe. His doctrine of Metamorphosis is not the discovery of something that has taken place, but the setting forth of an Idea, — Idea of Nature, Idea of Man, which meet at this point: and in his studies of colour he is so far from wishing to supplant an old theory by a new one, that he blames the inclination of men to “set aside phenomena“ by an explanation, instead “of making themselves acquainted with Detail by intimate sympathy, and so building up a Whole.“ 72 But our whole educational training makes us rather “historical“ beings than creatures of the present, and those two conceptions, Moment and Sight, are nearly related. The man who in the contemplation of Nature busies himself to trace back a so-called Effect to a so-called Cause, follows the path of the mathematician: for just as the one prefers the forms of pure perception, so the other prefers the forms of empirical perception to the prejudice of experience afforded by the senses: he will see keenly, but not clearly, for his vision is troubled by thought, that is to say, by systematic synthesis according to human Laws. Experience is, according to Kant, “a product of the understanding from materials furnished by the senses“; that it is in every case; but it makes a great difference whether the preference be given to the

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element of the understanding or to that of the senses; exact science does the one, Goethe the other. For Goethe the question is one of reproductive, or let us say boldly, of artistic vision, — (which can only be the case when it is allied to Genius) — in contradistinction to an abstract observation of Nature which exclusively busies itself with dissection and peering into causes. If any one should teach us to suppress, not for ever, but at pleasure, this involuntarily schematising activity of the intellect in the interest of vision, and as Goethe said, of “construction,“ he would be endowing us with new eyes. Just as the mathematical method has been enriched with new instruments, so would this method of pure observation enrich us with new thoughts and images. Richer than ever before would the source of phantasy flow, because science has in the meanwhile been extending the field of the Visible. Unless we follow Goethe's example our civilisation will evaporate into mere equations; Goethe has shown the road to culture.
    But it is not only Goethe who has shown it; Kant has done the same. If only you should obtain a living insight into the fact that Kant, — whose eye so plainly differed from Leonardo's and Goethe's, — yet shares the diametrically opposed views of both men in relation to the observation of Nature, and so leads to a harmonious adjustment between them, then the patience which you have shown to-day would be richly rewarded. You know how far he agrees with Leonardo: there is no difficulty about that: to perceive the agreement with Goethe requires a finer analysis. Yet it is such a distinct feature in Kant's being, that a few words will suffice to direct your attention to it. A later lecture will go further into this.
    Kant knew exactly what constitutes the principles of exact science. He writes, “we can speak of Light-matter, Heat-matter, etc., because they are mere fictions of forces

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which contain no more than a relative conception“ (Ur, III, 598). And the same man who said, “there can be no true recognition of Nature without presupposing mechanism as the foundation of natural investigation“ — you know exactly what he meant by that, and how he meant it, — the same man writes in the same place, “this is in no way opposed to the maxim to seek and reflect upon a principle in certain forms of Nature, which is a quite different matter from explanation in accordance with the mechanism of Nature“ (Ur, § 70). It is true that here Kant has in his head only a single other principle, that of Final Causes; still in this work upon the power of judgment other principles come into play which only indirectly affect the Final Causes, as for instance in the great discussions over the ideas of genus and species, metamorphosis and persistence of form, etc. The Final Cause is in general, as we see in many passages, considered by Kant as of identical meaning with architectonics. We are dealing then with “Nature as a presentation of Ideas,“ as the same work says, “an effort,“ as Kant had already said in the essay on Pure Reason, “which deserves respect and following up.“ I would bespeak your whole attention for the following sentence. Kant says, “Taken literally and considered logically, it is impossible to represent ideas. But if we widen our power of conception ... for the contemplation of Nature, Reason inevitably comes in, and brings forward the effort of the mind, vain though it may be, to make the representation of the senses adequate to these ideas“ (Ur, note to § 29). Here is a sentence which might have been coined from Goethe's mode of contemplating nature. To widen the empirical power of representation must be its keynote. It is just this very effort to widen empirical contemplation, — the share of the senses, in contradistinction to the preference of a one-sided and so to speak abstract contemplation — which fundamentally distinguishes

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Goethe's method from that of science. And notice how our dear dry Kant speaks: “taken literally and looked at logically“ ideas cannot be expressed, and the attempt remains “in vain“; yet no one hinders us from casting away the livery of the Literal, and the serf's chain of a Logic ultimately leading to absurdities, as Kant himself has shown in his famous exposition of the Widerstreit der Vernunft (the Antagonism of Reason). The idea “species“ taken literally cannot be shown to the senses, yet in spite of that it forms the foundation of all science of beasts and plants: the idea metamorphosis cannot hold out against logical investigation, yet it is an idea which lies at the root of all comparative anatomy. Science only widens extensively, while on the contrary a fashion of seeing after the manner of Goethe widens our “power of representing the perception of Nature“ intensively.
    It would of course be an absurdity to expect to find ideas working in a man like Kant, who kept his eyes closed, in the same sense as they did in Goethe. Descriptions alone gave him any lively conceptions; in no other way could he see anything. A direct contemplation of Nature, of the widening of which he speaks here, so far as Nature in the concrete is concerned, could not exist for him. Face to face with nature he could neither discover with Leonardo nor invent with Goethe. His ideas — ideas of genius — in regard to surrounding Nature, are accordingly purely schematic, purely mechanical. His theory of the heavens is a good example of the way in which the Physicist searches “for“ experience. But there is also an inner Empiricism, an inner nature. And here, here where Kant is quite at home, he stands in exactly the same position as Goethe stands in relation to surrounding, concrete Nature. There is indeed a form of idea which only in a case where the eye is directed inwards could develop itself to such a brilliant clearness,

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that it might at last, like the Holy Grail, blaze through the cavernous darkness, an idea whose counterpart, — what Goethe called the God-Nature, — is the idea of Freedom. The man who had followed the mechanism of Nature, not only in the construction of the world, but extending into the innermost folds of the intellectual activity of man, recognised moral independence as the highest power of human personality. That is an idea, an idea which may not be capable of being expressed, but which may well be “lived,“ exactly as Goethe's endeavour strove towards “living“ the Nature around him. So long as I take as principle the mechanism of natural investigation, so long I must look upon myself as a mere machine, or as Kant puts it “a Nature which the will subjugates“; I must be able to explain every most delicate impulse of my thought and feeling just as mechanically as the essence of Light, even though I should be compelled to premise for the purpose many “peculiar forms of motion of hypothetic media.“ Whoever denies that is working in the interest of obscurantism, and shows that he has no share in the blessing of true Teutonic science; for him the whole development of our knowledge of Nature from the fifteenth to the twentieth century has never existed. But does mechanism suffice for me? As a thinking and moral being am I not compelled to feel that if I go no further I am lying to myself? Does not the most intimate experience of every moment bear witness to freedom and responsibility? Does it not prove the reality of “a Nature which is subjected to a Will“? Remember how Goethe undertook the investigation of Light, not by the presumption of a hypothetical being, but by the faithful exposition of his dealings, his activities, and passivities. In the same way Kant repudiates the idea that we should search for the essence and the importance of being a man in the study of anatomy and in the comparison of the

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human skeleton with that of other genera of animals — the rather “are they only to be found in his dealings whereby he reveals his character.“ 73 Here you have, as you see, almost literally Goethe's words about Light. And what does Kant, the mechanician and analyst, discover when he puts these dealings to the test? “Man's freedom and independence of the mechanism of all Nature.“ But this view determines him to hold up before us men an idea (here called ideal because it leads to dealings which it is our business to make perfect), which is not taken up passively from so-called revelations, — which as a general proposition is not pre-existent and waiting for our coming any more than is the idea of metamorphosis, “but which may become reality through that which we do and that which we leave undone.“ Instead of theoretically debating about Freedom it is our duty to prove it by deeds; by Freedom we must realise ideals in defiance of Nature.
    Here you see Kant himself enlarging upon that which in respect of man's relation to surrounding Nature he had only discussed theoretically, namely the representation of Nature in ideas, as opposed to an explanation of her as mechanism. The connection with Goethe, which certainly does not lie upon the surface, is here so intimate and deep, that I hardly think that it is possible to understand the one man apart from the other. I do not think that you can attain a fully concrete notion, void of phrasemongering, of what Kant understands by “Independence of mechanism,“ and “Freedom,“ unless you dip deeply into Goethe's study of nature; and, on the other hand, I am convinced that our conception of Goethe's method of considering Nature remains dull, insufficient, and false, until we have realised that with him it is a question of something quite as direct, quite as truly experienced, as Kant's idea of the freedom of the human Will. Goethe, like Kant, wishes to carry out a work of

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salvation, and in the case of both men the method is the same. Kant on one occasion writes, “Two things fill the soul with ever new and increasing admiration and awe, the oftener and more persistently my thought busies itself with them: the Star-studded Heaven above me, and the Moral Law within me. It is not permitted to me to seek and only guess at either of these as shrouded in a veil of darkness, or in the Transcendental beyond the range of my vision; I see them before me and connect them directly with the consciousness of my existence.“ These words should remind you of Goethe's words, “Nature has neither Kernel nor Shell, she is everything at one and the same time.“ But for us men there certainly is a distinction between Kernel and Shell, and the inalienable tendency of our mechanical science, in other ways so admirable, is to make every thing into Shell, the star-studded heaven as well as the moral law: whereas Kant and Goethe are at one in this, — that they teach us how we are to begin to show everything as Kernel, in which — each following the nature of his special gifts — the one by preference fixes his eye upon the starry heaven, the other upon the moral law.
    Goethe's saying, “Instinctively I followed the same road as Kant,“ has grown more and more significant. It is my special hope that from Goethe's standpoint you are beginning clearly to see in its organic consistency the marvellous personality of Kant, so rich in what the superficial observer calls contradictions. Now, when you read the Critique of Pure Reason, and come across the often quoted and almost always misunderstood sentence, “I had to set aside Knowledge in order to make room for Faith,“ you will, I think, understand it, and that too, exactly in the sense in which Kant understood it. There we have a touchstone; for no man ever had a more glowing respect for exact knowledge than

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Kant, and no man read into the conception “Faith“ so little History and so much force of living actuality. To separate these two, Knowledge and Faith, and having done so once more directly to reunite them, — that was his special distinguishing gift.
    For to-day my task is accomplished, and at the same time I leave the sphere of these two first lectures. With René Descartes and Giordano Bruno we shall climb new heights, and much upon which we have already touched will appear to us in another light. Let me, however, in conclusion, say a few words about the great artist who has rendered us such conspicuous service. For it is Leonardo whom we have to thank for the incitement, indeed for the peculiar driving power, towards those considerations which have opened up to us so clear and deep an insight into Kant's inmost heart. Unfortunately we cannot in these lectures busy ourselves more minutely with that wonderful man: still a most cursory glance will now suffice us for the discovery of more than one feature of his relationship to Goethe and Kant, and this last recapitulation will at the same time spread a bright, transparent, and protecting varnish over the colours of the picture that we have obtained.
    Leonardo, who so exactly agreed with Kant in his estimate of mathematical and mechanical investigation of Nature, has left behind him proofs that he too knew how to distinguish between a Nature which subjugates Will, and a Nature which is obliged to subordinate itself to Will. He writes, La necessità è maestra e tutrice della Natura, “necessity is mistress and guardian of Nature,“ — that is Nature as Mechanism; and yet in another place he writes, il dono principal di Natura è libertà, “the chief gift of Nature is Liberty,“ that is Nature as Idea; and the confirmation of this Idea in man he sees with Kant in the signoria di se medesimo, “the Lordship over himself,“ that is to say, what the German sage

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called “Freedom from the mechanism of all Nature.“ This agreement is of itself interesting; it points to the fact that whoever understands mechanism as the principle of the explanation of Nature, and, without leaving the slightest loophole through which any extravagance of idea might slip in, maintains it consistently, must inevitably in this way reach a healthy idealism: the conceptions Necessity and Freedom do not exclude one another, on the contrary they mutually depend upon one another. 74 In the clearness of this recognition Leonardo is nearer to Kant than Goethe; the latter was not sufficiently a mechanist to be a pure idealist.
    But we reach greater depths in this parallel if we take into consideration the relationship of Leonardo the working artist to Leonardo the man. Leonardo the theorist is a keen but inordinately strict, dry intellect. Often, in the none too easy reading of his works, I have been compelled to think of Kant. There is the same hatred of exaggeration, the same distrust of all that might believe itself to be intuition and inspiration. To his disciples he never speaks of anything else but measurements and calculations and technical practices, and he never tires of impressing upon them the “copying of Nature as in a mirror.“ And now let us turn from his books to his works. Is what you find a copy, line by line, of a mechanically seen form? Is it not far rather a revelation of all that is invisible, indescribable, unthinkable, “seeking in an instant of vision to concentrate a thousand experiences“? 75 (Walter Pater). Never, with the possible exception of Rembrandt, has personality been so brought home to us: the most intimate secret of the soul rests, only half veiled, upon the peaceful features; his female heads are the living representation of what Goethe calls das ewig weibliche “the eternal feminine“; his figure of Christ has the significance of a fifth Gospel.

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The same magic rests upon some of the pen-and-ink landscapes from his hand:

als ob da drinnen ganze Weltenraüme wären
Wald und Wiesen, Bäche, Seen
                                       unerforschte Tiefen

“as if in them lay whole world-spaces, Forest and Meadows, Brooks, Lakes, ... unplumbed Depths.“

    And he, the empiric and mechanician, knew full well what secrets of the human spirit are here disclosed. Of works of genius, he says: questa non s'insegna come fan le matematiche, ... non si copia come si fa le lettere ... questa sola si resta nobile, questa sola onora il suo autore e resta pretiosa e unica, e non partorisce mai figluoli eguali à se. “This cannot be taught like mathematics or copied like letters.... This alone remains noble, this alone does honour to its author and remains precious and unique, and never gives birth to children that shall be the equals of Itself.“ It is useless to degrade the phenomenon of the human intellect to a matter of small importance, or to deny its existence, as we daily see attempted: it is a beggarly life which we prepare for ourselves in that way. True, the merciless realist calls man Rè delle bestie, “the King of Beasts,“ and he laughs at the monks and “other liars,“ who talk of the miracles of “the soul,“ where he, as anatomist and mechanician, has only found nerves leading to a brain; but now he steps up to the canvas and produces upon it an Idea — the Saviour, the rè degli uomini, the King of men, as his mind's eye has beheld him, a work which cannot be learnt and cannot be copied, and which can never give birth to a son like to itself. And we — we draw near full of awe, blest with happiness, enriched for all time. We do not doubt the secret connection between the great man of art, the man who investigated the geometry of space and perspective, who measured with compass and rule the position of every leaf on the tree,

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of every muscle in the face, — and the man who gave form to immortal ideas; but here again the relationship is the same as that of Kant's example of the starry heaven above me, the moral law within me: in combination they complete my being; but as cause and effect they stand in no relationship to one another.
    There are just two worlds. Two worlds which stand in opposition and in contraposition to one another, which at the same time imply and exclude one another. You may perhaps remember an important conclusion at which we arrived at the very outset of the present lecture: namely that these two worlds are sharply divided from one another: they lie separated as it were by a broad stream: on the one side a bridge, on the other a ferry, leads from bank to bank: there are no other means of crossing. The World of the Senses can in no way directly obtain access to Thought and Reason otherwise than by means of Schemes of the understanding, and on the other hand the world of Ideas can only attain visibility on condition of borrowing Symbols from the World of the Senses. That is a fundamental fact of the human intellect, a fact long suspected, and laid down by Kant for all time. Every attempt to deny this twofold existence, which is of the very essence of our nature, and therefore of universal nature, is offering up the one half of our being as a sacrifice to the other. The Mystics, among whom we must reckon intellects like Schopenhauer, either dispute the mechanical law, or violate it at many points, and thus play havoc with our understanding: the scientific Monist acts even more despotically: for while the one only repudiates the abstract mathematical, the other rejects the concrete evidence of the senses. The course of exact science refutes the first, every genius convicts the second of lying. And what I wish to impress upon your minds is that Goethe's creative ideas about organic Nature and the essence of Colour, and Kant's creative

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ideas about the construction of the human intellect, and about the connection between the two natures, should be accurately examined and judged precisely in the same way, as we examine and judge an original artistic production due to the pure creative power of Leonardo. We have sufficient evidence that men of true genius occupy themselves with exact Science: yet it is foolish to expect creative achievements from science as such. Whatever inspirations science brings to light are not original but practical discoveries of Nature; none the less does science deserve praise on that account: but it is a higher matter when Nature in man crosses over to the work of discovery, and in a paroxysm of the intellect gives birth to a new thing. But to measure this with a yard-measure is a ridiculous undertaking. It is only the free, open eye which will convince us here, not the Logic which is like the crutch of the blind man groping his way: the two methods, combined yet ever estranged, stand over against one another like the oscillations and colour. Granted that Goethe and Kant were both technicians, yet here too there is a mysterious connection between passivity and activity, between experience and idea, between empiricism and creative power, just as in what concerns the unconscious method of life, there is a connection between Scheme and Symbol, Technics and Phantasy. No man is further removed from the bungler, no man is more industrious, than the Genius. Fifteen volumes has the Weimar edition already devoted to works of Goethe on investigations of nature; turn over those leaves if you are minded to learn how tirelessly, with what painful accuracy, how soberly, the great man studied nature. Kant on his side has surrounded his solitude with such gruesome moats and fortifications of philosophical technicalities that much courage and persistence are needed to penetrate into the interior. And just as I could not avoid criticising Goethe the

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technician, so it will seem difficult to many people to subscribe altogether to the Kantian technics. But exactly as Leonardo, the mighty artist, placed ideas in living form before our eyes, so also did Goethe, the pure Seer of Nature, the founder according to Johannes Müller of a new ideal of Natural History, and so also did Kant, the august enlightener of the soul of man. Their works are creative achievements of Genius. These guide us to the inmost mysteries of nature very differently from the ways of mathematical science. For as Goethe teaches us, “the way of Nature is the way upon which you will of necessity meet Roger Bacon, Homer, and Shakespeare.“ This way, gentlemen, is the one which we seek to tread in these Lectures, the way upon which we meet Nature herself as she reveals herself in her noblest creatures. If I have succeeded, in ever so modest a manner, in leading you upon this road to which Goethe points, then there should arise before you the vision of three giants, Leonardo, Goethe, Kant, each standing out as a perfectly distinct personality: thrice the glorious eye of genius meets your own: a threefold stream of Light floods over your world.
 
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