SOURCE: “Leonardo as Philosopher,” in Three Essays: Leonardo, Descartes, Max Weber, translated by Ralph Manheim, Harcourt Brace & World, 1964, pp. 3-58.

[In the following essay, which was originally published in German in 1953, Jaspers provides “an account of Leonardo's philosophizing, describing first the character of his thinking, then its content, and its reflection in the painter's way of life.”]

INTRODUCTION

Leonardo has left us a few marvelous paintings in a poor state of preservation, notably the Mona Lisa and the Last Supper, a self-portrait whose authenticity is doubted, but which all who have seen it remember as the face of one of the world's unique great men, and thousands of pages of notes and sketches. In addition we have the reports of contemporaries and his influence on other painters, who echoed his ideas in their works. The barest glimpse of Leonardo can still be gained from the ruins and fragments of his painting, from his daily notes, and from his influence on others.

Leonardo is famous as the universal genius who could do everything, as the artist who inaugurated the classical art of Italy, but whose tragedy it was that he failed to complete many of his great projects. Since Vasari it has been generally held that he squandered his talents and is consequently inferior to Raphael and Michelangelo, who were artists in their whole being and completed innumerable great works.

He is famous as a scientist. He has been called the founder of modern science. But this has been questioned on the ground that he did not use the methods of the mathematical sciences in his investigations, that the similarities between certain of his formulations and the principles of the future science are misleading, that most of the machines he designed were products of his visual imagination and could not have been built, that his application of mathematics is very limited and nowhere commensurate with the scientific acumen of Galileo.

He has less frequently been called a philosopher, an allegation that others have resolutely denied, arguing that he was lacking in the power to construct systematic ideas and concepts, that his numerous references to philosophy are without cohesion, and that he did not share in the continuity of the philosophical tradition.

It has been asked: was Leonardo essentially an artist or a scientist, or a philosopher, or something that cannot be subsumed under any of these established categories of intellectual endeavor? Leonardo became a mythical figure, the incarnation of mysteriousness.

Historians of art, of the sciences, of philosophy, have communicated the results of intensive investigations. From Goethe to Jacob Burckhardt and down to our contemporaries, men have tried to state what has moved them in Leonardo, to recall what has been forgotten, to restore what has been lost, to reveal the hidden.

I shall attempt to give an account of Leonardo's philosophizing, describing first the character of his thinking, then its content, and its reflection in the painter's way of life. Finally we shall look into Leonardo's particular greatness, which perhaps transcends the distinction between artist, scientist, and philosopher.

I THE CHARACTER OF HIS THINKING

1. Leonardo's thinking—and this is its distinctive feature—is based entirely on the eye and the hand. What has existence for him must be visible; what he knows must be brought forth by the hand.

Leonardo praises the eye. It is less deceptive than the other senses. It reflects all the works of nature. Only through the eye can the beauty of the world be enjoyed, and solely for the sake of this vision is the soul content to be confined in its human dungeon. The loss of sight leaves the soul in a dark prison, without hope of ever again beholding the sun, the light of the whole world. Thus there is no man who would not rather lose the senses of hearing and smell than that of vision.

Goethe describes the consequences of this identification with the eye. Because Leonardo's “grasp of nature was directly visual, because his thinking was grounded in the phenomenon itself, he hit upon the truth without detours.” “As clarity and discernment of the eye belong to the realm of intellect, so our artist was in complete possession of clarity and intelligence.”

But what the eye perceives becomes clear only when the hand creatively reproduces it. In dissecting an organism, the hand thinks in movements without words, and it does the same in drawing from nature or in projecting a design of the imagination, which creates what nature had not produced before. This thinking, not in concepts, but in lines, forms, and figures, is vision and action combined. The ancients disparaged painters as artisans. Leonardo reversed this judgment. In his view, nothing that arises in the mind through contemplation can attain perfection without a manual operation. The “theory of painting” leads to the “activity” of painting, which is superior to the mere theory. Thus Leonardo's thinking—and he himself looked upon it as thinking—was at once vision and action; it was thinking vision, vision made manifest by the work of the hand.

But the eye and the hand achieve knowledge neither by passively looking at things nor by blindly manipulating them. The visible becomes truly visible only through thinking action. This thinking action consists of two steps.

With the help of mathematics it creates and finds structure in the fluid chaos of sensation. It is mathematics that first makes possible an exact vision of things. “No human investigation can be called science unless it operates by way of mathematical representation.” Leonardo has in mind a concrete, visual mathematics. By mathematics he understands all order and law accessible to the eye.

But for Leonardo mathematical insight into the orders of reality is not yet a knowledge of the real. It must be accompanied by a penetration into the particular, into the endless detail of real perception. Consequently he criticizes impatience and the passion for abbreviation. Men, he laments, wish to grasp the mind of God, which encompasses the universe; but they behave as if they did not have time enough to acquire a thorough knowledge of a single detail such as the human body. He himself, as Hegel said of him, went into such details “with almost morbid thoroughness.”

For Leonardo the visible is known only through the tension between ordering structure and endless particularity. He never strays into fantasy. He always shows visually what he thinks, and he always thinks what he sees. Amid all the richness of his sensuous visions, he remains sober. He does not strive for special powers with which to contemplate the supersensory, but lives entirely in the real world; within it he preserves human proportions and remains a man speaking in terms intelligible to man.

Leonardo insists on perceptibility as the condition of certainty. Without the eye and the hand, nothing would exist for him. For something to be, it must be visible and tangible. All “things are doubtful that defy the senses—for example, the nature of God and the soul, concerning which men dispute endlessly.”

2. But Leonardo has more than this in mind. He does not content himself with the tangible and the visible. His philosophizing is far removed from ordinary empiricism and sensualism. Everything that can exist for us, he believes, is in some sense reproducible, not only the external nature that already exists, but also and above all the ideas that emerge in the mind, the potential reality. Knowledge is not random reproduction (comparable, for example, to our photography), but a bringing forth of what the mind sees. It ranges from the drawing of possible machines conceived by the technical imagination to the painting which manifests the invisible in the visible, and includes an awareness of the symbolic character of all visible things. The imagination opens up accesses to being, for which the artist creates visible figures; it is only through the truth of these visible things that being becomes truth.

Leonardo speaks of visible surfaces. What does not become surface does not exist. But in the surface we must see the ground; we must learn to see through the sensuous surface to its asensory origin. The origin speaks in the surface, it can, as it were, be grasped, but not by the mere senses.

From the standpoint of method, this is the crux of Leonardo's thinking. Everything that is real passes through the senses. But what the eye and the ear perceive is itself spiritual when seen in the right way. Within the sensory world we are always soaring above the sensory world, but not into a realm beyond the senses. And conversely: in order to exist for us, the spiritual must become surface.

Throughout his Treatise on Painting Leonardo speaks of the spiritual in the sensuous, of number, form, and reason in the concrete world. It is in this light that he treats perspective, proportion, the elementary laws of movement, the structure of organisms, the expression of constant character traits in the structure of faces and bodies, and of momentary passions in gestures, and so on. But these insights, which comprise Leonardo's “science of painting,” are by no means the ultimate secret of the spiritual. Leonardo does more than he says; of this he was aware, as he shows in occasional propositions, though he never states it systematically.

If it is true that his few pictures produce a unique effect on us, what is its source? The smile, the charm, the landscape as the background of man's being—are these in themselves the essential? Do these pictures affect us as they do because every last brushstroke is a product not only of intuitive creation but also of thought? Or because they matured in the lucidity of a philosophical consciousness? Do Leonardo's search for the true nature of being, his investigations in the universe, enter into the content of his pictures? Perhaps an indication is provided by two celebrated and fundamental features of his painting—his composition, which made him the founder of so-called classical art, and his use of chiaroscuro.

Pictures in which every detail throbs with life, but in which the whole is a unity thoroughly composed and in which nothing exists haphazardly for itself—this came as a revelation to his contemporaries and opened up a new world of art. Leonardo made a discovery which in essence could never be repeated. He found a cipher for the unitary order of the cosmos. In so doing, he achieved a classical perfection in which formula and convention had not yet made their appearance, the sublime and ceremonious, the pompous and decorative are still absent. But for Leonardo this cipher of perfection is only a part of his work, a step, not the conclusion.

Chiaroscuro seems to be the exact counterpart of this perfection of form. Hegel called it a magic of colored illusion, in which objects evaporate. The deepest shadows are suffused with light and rise by way of imperceptible transitions to the brightest radiance; nowhere is there a harsh dividing line. Objects dissolve in an objectless play of reflected illusions, which blend into other illusions, becoming so spiritualized that they verge on the realm of music. What Hegel intimates with these words was first discovered by Leonardo. It operates like a cipher of that which makes all objects transparent; with the pure surface of the most fugitive object it opens up a dimension that would be hidden by a solid bodily representation. What Correggio carried further and allowed to get lost in sensuous enchantment, what Rembrandt embodied through another unique metaphysics, has its beginning in Leonardo, as a new way of making visible the invisible—through the process of thought.

The character of spirituality in Leonardo's creative intention is also manifested in his attitude toward his work. He no doubt intended to finish his works, but with him completion was not an ultimate aim or criterion. The purpose of his visual thinking transcends the finished work.

It is no accident that Leonardo was not satisfied with any of his works. He was unable to complete his paintings, because his intention went beyond the limits of the work. In the Last Supper—it is believed—neither Judas nor Christ was finished. Goethe formulated an old explanation: “He was unable to complete either the betrayer or the God-man, because they are both mere concepts that are not seen with the eyes.” A higher meaning strives to make itself visible, but the visible work is not adequate to it. The essential expresses itself in something that shatters the limits of visibility or in an incompleteness that leaves the solutions open. In this indeterminate visibility the invisible speaks, but it can no longer be seen. We glimpse a transcendence which nevertheless remains hidden; the incorporeal in the corporeal speaks to us. The work as it stands says more than any perfection. Even in the seeming perfection of Leonardo's finished work there is something that points beyond it. Leonardo himself never formulates any such idea. But this interpretation seems to explain why he was never satisfied with his finished work.

Then there are the sketches and experiments in which Leonardo did not even strive for perfection. He took ugliness for his subject, depicted real and possible deviations and abnormalities. He did sketches of cosmic events impossible to visualize, pictures of the end of the world, or of rainstorms. His head was full of chimeras, said Castiglione when the aged Leonardo was in Rome.

It is hard to speak of individual pictures. A Frenchman has said that all those who speak of the Mona Lisa lose their reason. The open eyes under the high forehead, the barely suggested smile, the quietness of her attitude, the aristocratic negligence of the folded hands have made spirituality visible in the corporeal figure of this woman. It seems likely that in the ephemeral person Leonardo perceived the eternal idea of nobility, which he identified with human reason. In her there is no coquetry, no seduction, no social mask, but only the serene aloofness of the soul. In lucid awareness she combines heart and mind, love and thought, and maintains the tension between them. Leonardo saw the dignity of woman, of which her sexuality is only one component. This spirituality in the corporeal is beyond understanding; it transcends everything that Leonardo was able to teach in the Treatise on Painting.

In Leonardo the clearest visibility takes on a dreamlike quality because it points to essential reality. His objects are not vague; they are sharply defined but transparent. He knows no degrees of reality, no cosmic hierarchy as in the medieval view of the world, but the one reality, which is the Encompassing and in the Encompassing. But he knows different kinds of vision, namely, the blind vision for which a reality without transparence is everything, and the true vision, for which all the things of the senses become spiritual, as though the invisible were the true reality.

3. The problem is thousands of years old. Because art must be sensuous and can be spiritual, there is a sharp dividing line between the art which, for all the splendor of its artistry, is confined to the world of the senses, and the art that is the language of transcendence. With all its magnificence the art of pure visibility seems insubstantial beside the art which discloses the invisible; the impulse to enrich life pales before the attraction of eternity, the vitalization of the spiritual before the spiritualization of the living flesh.

Accordingly, philosophy, from Plato to Augustine to Kierkegaard, has claimed the authority to judge art, music, and poetry for the good and evil in them. The mere thinker who examines works of art and takes a critical attitude toward them consults a philosophical authority in the artist or poet himself.

Leonardo did not speak with the clarity of those great philosophers. But he shared in their struggle for the spiritualization of the sensuous. Sensuous reality is indispensable; without it there would be nothing but empty abstraction. The spiritual is the essential; it must not be engulfed by vital impulses, by the passions, by the sensuous figures in which it appears, for then there would be nothing but an intoxication of the senses and a reality without transparence. Nothing is real unless it enters into the realm of the senses. But the sensuous as such, the purely sensuous, is empty.

Leonardo may be regarded as one of those artists who have most astoundingly expressed the corporeity of the spiritual and the spirituality of the corporeal.

How did he accomplish this? A number of his remarks throw light on the matter. “Unfortunate is the master whose work is in advance of his judgment. Only one whose judgment towers above his work can move toward perfection in art.” But according to Leonardo this judgment which guides artistic creation has two stages. First there is the judgment which unconsciously deludes itself. Then there is a judgment concerning this judgment.

Leonardo describes the first kind of judgment. The artist's own physis involuntarily reproduces itself in the figures, gestures, movements of the work. “For the soul, master of the body, is itself one and the same as your judgment, and delights in works which resemble that judgment which it created by constituting your body.” “This judgment is so powerful that it guides the artist's hand and causes him to repeat himself.”

But this living soul, which in equal measure constructs the artist's body and guides his work, governs the creation of the work only until “it becomes our own judgment.” This true, “own” judgment sees through the other unconscious judgment. It comes to itself by constant listening to the judgments of others, by the practice of different styles, whereby it achieves harmony with all other judgments and rises above them.

Where the artist's own physis erupts blindly through its judgment and then remains captive to its individual vital essence, the result is works determined solely by the artist's nature. If this painter is “a fool,” his paintings (in narrative cycles, for example) “are without coherence and conciseness; the figures take no account of their function, one looks in this direction, the other in that, as though in a dream. Thus every psychic and bodily state represented in the picture follows the nature of the painter.” But if the painter's judgment is superior to his work and to the judgment of his physis, he is enabled to give proper guidance to his work.

In other words: the artist is master of his work as the thinker is master of his thoughts. He exercises this power by reflection. His judgment penetrates to every ramification of what his creative mind and his hand produce. This accounts for the length of time Leonardo spent on his works. Such judgment did not impede his creativeness, but stimulated and purified it. It was not the ruin of his work (like the artist's thoughts in Balzac's story about the unknown masterpiece), but its element. Leonardo's creative power increased with the power of his reflection. His work is the opposite of blind activity. The inexhaustible spell of Leonardo's pictures may well stem from this unity of thought and artistic ability, from Leonardo's fundamental attitude—all art and more than art—which placed him above his work and enabled him, thanks to his imagination, to express what cannot be said in words or formulated in terms of ideas or perceived by a passive looking at things, but attains conscious presence through thinking vision.

4. Leonardo's vision, this perception of the spiritual in the corporeal, helps us to understand the nature of his science and the attitude that governed his scientific investigation. Leonardo is rightly regarded as one of the creators of modern science. But in what sense?

A. For him, to know is to reproduce. In drawing and painting, in the fashioning of tools and technical devices, in scientific experiments, the work of the hand and the eye is at every stage bound up with, and completed in, visual reproduction.

The human body, says Leonardo the anatomist, cannot be represented in words alone. “For the more closely you describe it, the more you will confuse the reader. Consequently, you must picture as well as describe.” In Leonardo's anatomical studies the drawing almost crowds out the text. He analyzes and clarifies his ideas in the act of drawing. With Leonardo, drawing became a method of investigation in the morphological sciences. Anatomists, botanists, geologists revere him as a master. He created the visual thinking that develops from drawing.

The objection has been raised that knowledge and vision are two different things, that to see is not to know, that clear form is a question of aesthetic judgment and not a scientific finding. This is not so. In all morphology the draftsman works under the guidance of the scientist, the scientist himself works as a draftsman. This visualization, to be sure, cannot discover any natural law requiring measurement, experiment, formula. But it opens up a characteristic field of knowledge, which is first discerned in the image, though like all science it requires language for explanation.

Leonardo has also been criticized for identifying graphic reproduction and art. It is argued that scientific drawing represents facts, while art creates a vision, that scientific drawing deals in empirical reality, whereas the essence of art is to convey meaning. Leonardo is himself aware of the difference: painting, he says, derives its power, first from following nature, then from outdoing nature through creation. In both cases knowledge is embodied in a formative activity. The anatomical draftsman does not photograph; he abstracts and constructs the essential. But in so doing he does not invent; he finds what is already there, whereas the artist, working with what he finds, arrives at something new. The dividing line is fluid, as may be gathered from Leonardo's physiognomic sketches and the drawings of horses in which he varies their movements ad infinitum.

B. Knowledge is based on sense perception. “All knowledge is futile,” says Leonardo, “that is not born of sense perception, the mother of all certainty, and that does not end in visible experiment.” He denies that “there is truth in sciences which from beginning to end remain in the mind, chiefly because in such purely intellectual processes experiment has no place, for without experiment nothing can be known with certainty.” Thus knowledge does not reside in passive looking on, but in activity. The passive man is a mere parrot, the inventor is active. The inventor is the mediator between nature and man.

C. As a modern scientist, Leonardo strove for certainty. A reliable insight that stands up to inquiry is invaluable as such. “So contemptible is falsehood that, even were it to praise the works of God, it offends against His divinity; so excellent is the truth that it lends nobility to the most trifling things that it praises. Thus the truth, even when it deals with base and insignificant things, is infinitely superior to all sophistries and falsehoods concerning the highest and most sublime problems of the intellect.”

D. Modern science is universal. The striving for universality is dominant in Leonardo. All reality is worth knowing. The range of his interests was unlimited. Whatever exists, let it be seen and known.

E. In its consciousness of progressing toward the infinite, in its eagerness for discovery, modern science is open to the new and free from traditional opinions. Imbued with this striving, Leonardo passed from a grandiose but closed and unreal world into a world that is open to reality. For him realities were no longer examples confirming what was already fully known; they demanded to be examined in themselves and known in every detail. Rejecting authoritarian total knowledge, he moved forward, searching and finding. He reduced the old metaphysical abstractions to means of expression, useful for the formulation of his thoughts, but without validity in themselves.

Reproduction, reliance on sense perception, the striving for compelling certainty and universality—these impulses characterize Leonardo as a modern scientist. But when we look into the actual content of his science, limitations will become apparent.

1. Leonardo's discoveries, especially in anatomy, botany, and geology, are not guided by a constructive theory in the modern sense, but spring from an optical view of things, guided by an all-embracing cosmic consciousness.

Thus in describing the human form, he aspires to “reveal the nature and habits of men.” In his projected work on anatomy, he announces his intention of showing the development of the organism from conception to uterine growth, from the one-year-old child to the adult man or woman. Then he would proceed to represent the basic states of existence in bodily terms: joy in the different ways of laughing, suffering in the different ways of crying, combat “with different movements bearing witness to killing, flight, fear, boldness, and homicidal frenzy,” the exertion involved in pulling, pushing, carrying, holding, supporting. Modern anatomists admire the precision, fidelity, and clarity of his anatomical drawings, but are disappointed at the absence of all the principles of modern anatomy: the idea of comparative anatomy or of a system taking in the animals and plants, fundamental plans underlying the structure of the organisms, the basic vital functions. They are amazed that Leonardo should have drawn the structure of the heart correctly even in detail, but clung to Galen's conception of the movement of the blood despite its incompatibility with his own anatomical findings. Leonardo seems to stop where observation requires an encompassing conceptual view to lead it to new observations. Observation is guided by observation and not by a motivating abstraction. Though he employs many traditional concepts, such as “natural motion” and “center of the world,” he does not think them through systematically, but employs them inconsistently to express his observations, and not for their own sake.

2. Leonardo writes: “Let no one read me who is not a mathematician according to my principles”; and “mechanics is the paradise of the mathematical sciences.” “The instrumental or mathematical science,” he says, “is most noble and extremely useful.” Why? Because “by means of it, all living bodies that move perform their activities.”

On the strength of such statements, Leonardo has been regarded as one of the founders of modern mathematical science. But this view is not tenable, unless it is merely taken to mean that the general interest of the Renaissance in mathematics, its passion for technical contrivances, and the activity of the workshops created favorable conditions for the subsequent growth of the exact sciences.

Leonardo, it is true, speaks a good deal of mathematics. We have many mathematical drawings from his hand. But one cannot help noting how small a part mathematics played in his actual investigations of nature. In speaking of mathematics we may have in mind pure mathematics as a discipline of the constructive mind, dependent on nothing but its own evidence; mathematical science, in which mathematics goes hand in hand with observation; and finally, the mere calculation involved in technology. Leonardo made no original contribution in any of these departments.

It may be asked whether Leonardo understood the nature of mathematics. For practical purposes, in any case, it meant no more to him than the geometry that added clarity and precision to his diagrams, or than utilitarian arithmetic. Leonardo's thinking was often geometrical, more rarely arithmetical, because even arithmetic is less visual.

We must not look for the spirit of mathematical science in Leonardo. He was unfamiliar with the rigorous method of the scientist who elaborates a mathematical construction, interprets its consequences, and verifies it by experiment. Such procedure alone would have placed him in the community of true mathematical scientists, who advance into the infinite by secured stages. To him mathematics was merely an instrument for the exact representation of observation, never a means of pressing beyond observation and, by reducing experience to a minimum of measurements, of penetrating the world that has opened to mathematical science. For Leonardo the visual image remained the essential; thinking as he did, he could never have reduced it to the rank of a mere point of reference. In the visible world he sought for an invisible which expresses itself precisely in a qualitative abundance of forms. He did not look for physical laws, which cannot be represented graphically, but expressed only in quantitative or formal mathematical symbols. On the contrary, his investigations were a series of quick raids—he made discovery on discovery by observation and graphic representation, but failed to follow them through. He did not go beyond the visible to derive the process of the invisible and verify his theory by measurements. Radically committed to observation, he could not go beyond it. By their universal character certain of his statements seem to anticipate principles of mathematical science. In Leonardo the worlds of Newton and of Goethe had not yet parted. But in him the prevailing spirit was that of Goethe, not of Galileo or Newton.

For Leonardo, mathematics and mechanics remained a world of the visual and tangible, of what can be made in space with the hands, either directly or with the help of machines. He studied the mechanics of the body as he studied the mechanics of machinery. Both are functions of all-embracing life. In the light of the subsequent separation between mechanics and biology, Leonardo's conception is ambiguous.

In considering the priority he accorded to what is visual and alive, it is simple to say that Leonardo was not a modern scientist. But when we consider the implications of his mechanical view of the life process and the conception of the organism as a machine which, in the period beginning with Descartes, was to obstruct all true biological knowledge and inquiry, we must condemn Leonardo as a precursor of this fallacy. Leonardo was not yet aware of any contradiction between mechanism and vitalism. To him mechanism was a means of visualizing the structure of motion, not a general theory of process.

Thus Leonardo may be identified with the spirit of modern science, but not of mathematical science. Yet it should be remembered that mathematical science is only one component, and not the determining factor in the grandiose edifice of modern science.

Leonardo's modern scientific attitude is attested by his hostility to magic, to belief in spirits, and to all the opinions which spring from imagination uncontrolled by critical observation. He insists on reality. And what is real must come to us through the senses, the eye, through verified experience.

Leonardo attacks the prevailing belief in spirits. There are no such things as disembodied beings in space. In the realm of the elements, there is nothing without a body. “The spirit has no voice. There cannot be any sound without a movement or percussion of the air. But there cannot be a movement of the air when there is no instrument. Nowhere is there an instrument without body. Since this is so, a spirit can have neither voice nor form nor force. And if a spirit were to take on a body, it could not pass through a closed door.” Spirits are an impossibility. Neither they, nor the human magicians, who lift enormous weights, provoke storms and rain, transform other men into cats and wolves, can ever have existed. For if they had existed, they would have been more powerful than any army, they could have destroyed any fleet by stirring up tempests; they would inevitably have become the masters over all nations. Hidden treasures and jewels would have been visible to them. They would have flown through the air in all directions, from one end of the universe to the other. If such an art existed among men, why did they not preserve it? Moreover, if it had existed, how can it be that the world still endures? For there are many who would destroy God and the whole world to satisfy a single one of their desires.

Leonardo attacked the makers of gold. He praised the alchemists for the useful things they invented; but in trying to make gold they are led into error by an insane avidity for gain. Nature alone produces the elements. From them man produces an infinite number of compounds. He cannot produce the simple original substances. No alchemist has ever succeeded in artificially producing the least of the things that can only be made by nature, not to mention gold which is in truth begotten by the sun.

He assails the speculative chimeras, the hair-splitting and delusions of those who babble about sublime and mysterious things. “Will you take refuge in miracles and write that you have knowledge of things which are inaccessible to the human mind and of which there is no demonstrable specimen in nature?”

In opposition to magicians, alchemists, and speculative visionaries, Leonardo advises his readers to confine themselves to what is within their reach. Men should not waste their powers on futilities in disregard of the actual possibilities. Let them hold on to the things of nature, instead of attempting the superhuman, dig for gold in the mines instead of ruining themselves trying to make it. For “nature avenges herself, so it seems, on those who try to work miracles; they will possess less in the end than other men, who are more prudent.” Such will be the lot “for all eternity of the alchemists, the would-be creators of gold and silver, and of those supreme fools, the necromancers and magicians.”

To sum up: Leonardo's scientific endeavor brought forth numerous genuine discoveries in the empirical world, but each remained isolated, he did not integrate them into a guiding scientific theory. He arrived at discoveries through empirical mechanics, the morphological conception of organisms through practical manual operations. His fundamental attitude, however, was not a theory, but an all-pervading view of nature as a living totality.

II THE CONTENT OF HIS THINKING (METAPHYSICS)

A conceptual system of the world as a whole was alien to Leonardo's thinking. He took up every possibility of thought, but none became an assumption with him. With every observation he began all over again. The infinite detail of natural phenomena served him as a guide in the contemplation of the All, which is represented and perceived in every particular. To him, observation was not merely a means of confirming his opinions; he approached things without bias, experimenting, playing, as it were, with ideas and images, without fear of contradictions. He lived in the world as a whole, but he experienced it only in the particular. The scientific discoveries that he left behind him were mere by-products of his quest.

1. The cosmos is not only mechanism; it is all-pervading life. The earth as a whole is also a living organism. Its flesh is the soil, its bones the strata of rocks, its blood the water in the veins. The ebb and flow of the sea are its breathing. Its body heat is provided by fire. The seat of its life is the fire that erupts in curative springs, sulphur pits, and volcanoes.

The world is a unity. From this unity derive principles such as: each thing tries to maintain itself in being, but each thing strives to be whole, to escape its incompleteness. Mechanical principles also point to this unity: nature carries out every action in the shortest way. Once the cause is given, the effect occurs in the shortest possible way. The earth is moved from its position by the weight of a little bird that settles on it.

The core of all things is energy. When a wave in the surf breaks against the beach, dies down, and is carried onward by the next wave, when the power of a stream enters into a whirlpool that nothing can resist, when horsemen do battle and horses in endless formal variations disclose untrammeled power, when the emotions speak in the faces and gestures of men, they all bear witness to the same thing: motion springing from energy. Leonardo's energy was nothing like the concept of latter-day physics. He dimly anticipates such concepts, but only as partial aspects of the total energy which he calls an “invisible power,” a “supersensory power,” a “spiritual, incorporeal power.”

Leonardo describes energy. This invisible force has its source in living bodies. From them it is transferred to inanimate bodies and gives them an appearance of life. Without it nothing moves, no sound or tone is produced. Energy is infused in bodies by an external power, they are diverted from their natural state of rest. It is a wonderfully effective vital force, compelling all created things to change their shape and position. A body that is in its grasp has lost its freedom. Energy is in conflict with what it dominates. With overwhelming force it expels whatever resists it. Itself hard pressed, it overpowers all things. It is increased by resistance. But in this struggle it does not endure. The motion it induces does not last. It grows great in conflict, in peace it wastes away. The greater it is, the more quickly it consumes itself. Slowness makes it strong, swiftness makes it weak. While compelling all things, it rushes with furious speed toward its own dissolution.

Leonardo speaks of this energy almost as though of a living being: it consumes itself involuntarily. It lives in necessity and dies in freedom. It is forever striving to lose and waste itself. It impetuously drives away whatever resists it; but at the same time it banishes what opposes its dissolution. In struggle it overcomes its cause, namely, resistance; it kills resistance but at the same time itself. As resistance increases, it becomes more powerful, but thereby runs headlong toward the death it desires. Its great force magnifies its drive toward death. But such a drive is paradoxical, for all things strive to escape death, and force itself is only such a striving.

In all phenomena Leonardo “sees” the power that he calls invisible. He sees it in the struggle between the energy of the spirit and the inertia of lifeless matter. As it increases in intensity, this struggle between life and death destroys life, but death is immediately surpassed by new life. Struggle itself is the restless, indestructible principle that transcends life and death.

The most magnificent thing in this world of forces is the sun, which Leonardo praised as Ikhnaton did before him and Goethe after him. In the whole cosmos, he says, I see no body that is greater and more powerful. Its light illumines all the heavenly bodies. All souls have their source in it, because the warmth in living creatures comes from the soul. There is no other source of warmth or light in the universe. He admonishes those who prefer the worship of men, or the worship of gods such as Jupiter, Saturn, and Mars, to that of the sun.

2. Our earthly world was not always as it is today, and someday it will end. Leonardo sees the world in process of drying out and burning: the air will be thinner and without moisture, the rivers will run dry, the soil will lose its fertility. The animals will starve. Man will take many measures to preserve himself, but in the end he will be doomed to die. The once fruitful earth will be barren and empty. And then the earth will be destroyed by the element of fire. Its surface will burn to ashes. Probably, says Leonardo, that will be the end of earthly nature.

Leonardo's prophecies are a product more of perception than of thought. He saw the past and future in the present. The fossils he collected showed him the life of a remote past, when there was ocean where now there are mountains. His famous exploration of a cave gives us a moving expression of what he looked for and how he looked: “Impelled by an ungovernable longing to behold the vast abundance of the varied and strange forms that nature has created … I came to the entrance of a large cave. Bending my back, my left hand clutching my knee and with my right shading my lowered, contracted eyebrows, I peered to see if there was anything to be distinguished, but the deep darkness impeded my view. After I had been there for some time, two feelings stirred within me: dread of the gloomy, menacing cave and desire to find out whether there was anything marvelous in it.” Leonardo made his way in and was lucky enough to find an enormous skeleton. At once he saw it as a living creature: “O mighty, once living instrument of constructive nature! Your greater strength was of no help to you; you too were compelled to leave your tranquil life and obey the law which God and time impose on creative nature. Of what avail were the branching, sturdy dorsal fins with which you went your way, impetuously dividing the salt waves with your breast in pursuit of your prey. … Here you rest now, destroyed by time, at peace in this narrow space, your bones, bared of skin and flesh, forming an armor and a prop for the mountain on top of you.”

Leonardo described and depicted natural catastrophes, the end of the world, the deluge. He perceived the primal forces of the cosmos through their creative workings and the destruction of their creation; he identified them with the one all-embracing necessity. Some of his drawings suggest atomic explosions. But the incongruity of such a comparison shows once again the radical difference between Leonardo's view of nature and modern mathematical science. For Leonardo the primal forces are the secret and limit of all things; they are the destruction of nature by nature, whose manifestations we perceive but not its forces. For modern physics, by contrast, the primary forces are knowable and largely known; they are invisible, unrepresentable forces, accessible only to an unintuitive mathematics; dormant in matter, they have now been seized upon by man and made available for his purposes. Leonardo's science is the mechanics of perceptible masses and at its limit a description of the rise and fall of the cosmos. Modern physics is the knowledge of the primary forces of matter and a technique making man the potential destroyer of the cosmos, or at least of the planet.

Leonardo represented the world process in his so-called “prophecies.” His pictures of the future are mere extensions of the present, not datable predictions of definite events. Along similar lines, his “fables” express wonderment at the destinies of man, noting what is and asking questions, but making little attempt to answer them. Mingling metaphor and immediate observation, he builds up a view of existence by observing what happens in nature, what men do to animals, the customs and occupations of men.

At the sight of a donkey being beaten, Leonardo reflects: “O indifferent nature, why are you so unjust to your children? … I see your children given to others in bondage, without ever deriving any advantage for themselves, their services requited by the worst mistreatment, and nevertheless they devote their lives to the welfare of their tormentor.”

Leonardo relates the ruthless acts of men to what they themselves suffer at the hands of nature. Of cannon: “From beneath the ground will come something that will deafen those nearby with its terrible roar, that will kill men with its breath and destroy cities and castles.” Of firewood, lime kilns, and boiled fish: “The trees and shrubs of the farflung woods will turn into ashes. … The earth will finally be made red by days of burning, and the rocks will be changed into ashes. … Creatures of the water will die in boiling water.”

Hearing the cries of infants being swaddled, he writes: “O cities of the sea, I see your inhabitants, women as well as men, fettered by strangers who do not understand our language. And only in sobs and laments will you be able to vent your grief at your lost freedom, for those who fetter you will understand you no more than you understand them.”

Watching ants, he thinks: “Many communities will hide in dark caves and sustain themselves and their families for many months in darkness”; considering the lot of the bees: “Many others will be robbed of their provisions and then be cruelly immersed and drowned by unreasoning men”; and of cows: “Their little children in countless numbers will be carried away to slaughter.” And he concludes: “O divine justice, why dost thou not awaken?”

He describes the cruelty of men, which will show its full fury only in the future: “Then creatures will be seen on earth who fight one another unceasingly. … There will be no limit to their wickedness. And when they are glutted, they will satisfy their lusts by spreading death and suffering, affliction, fear, and terror among all living beings. In their boundless pride they will even try to storm the heavens, but the weight of their bodies will hold them down. Then there will remain nothing on earth, under the earth, or in the water, that they will not hunt down, ferret out, and destroy, and nothing that they will not carry away from one country to another.” And again Leonardo concludes: “O earth, why dost thou not open? Why dost thou not fling them into the deep crevasses of thy giant chasms, and cease to offer heaven the sight of so cruel a monster?”

But Leonardo also sees smiling opportunities for man. The enthusiasm with which he set out to invent a flying machine is only the most striking instance of the hopes he attached to technical invention, both for its utility and for the new experience of the world it would open up. He envisaged the development of the mails and of other means of communication: “Men in countries far distant from one another will speak together and touch and embrace one another, although they are in different hemispheres, and they will understand each other's language.”

But in times of calamity men will succumb to madness: “They will hear animals speak in human language. They will see a glittering light in the darkness. … They will appeal to statues of the saints, but the statues will not hear them. They will obtain no answer. They will beg mercy of him who has ears but does not hear. They will offer up candles to him who is blind and clamorously implore him who is mute.” On the occasion of a funeral: “They will show the greatest honors to men who can know nothing of them.” And Leonardo concludes: “O strange mankind! What madness has driven you to such a pass?”

Leonardo was aware of transience, even in what is seemingly most enduring; he saw the corrosion of all things, and saw the cosmic process as a series of catastrophes. What happens today will happen for ever; he saw each barely perceptible incident from the standpoint of the whole; the evil that was done before his eyes would come upon all men.

But Leonardo's cries of horror were more lamentation than accusation. They are not prophetic agitation, not calls to rebirth, not penitential sermons. He merely contemplates the natural process, comprehensible in part, but though visible incomprehensible as a whole, the process which brings forth the cruelty but also the splendor of every day. “It is so”: that is the end of his horror.

3. It is strange when Leonardo, this always visual thinker, touches on the abstract. For it too must take on a kind of visibility.

He speaks of the fundamental form of happening as the envelope of things, and gains an intimation of dialectic: The forests will bring forth children who will help to kill them: the ax handle. A wall that harbors tiny seeds in its crevices will be destroyed by their roots. In growing, the power of nature devours itself.

The thrushes were glad that the owl had been caught, but through the lime-twig this same owl caused them to lose not only their freedom but their lives as well. Countries are glad when their overlords lose their freedom, although the consequence is defeat at the hands of their enemies, who deprive them of their freedom and often of their lives.

We produce the opposite of what we strive for. Man scrimps and saves for fear of poverty, in the illusory hope of someday enjoying the goods he has earned with so much hardship. The more you try to escape misfortune, the more miserable and uneasy you will be. In the belief that they are running away from horror, men race like madmen toward its boundless power. Many busy themselves trying to lessen it, but the more they take away from it, the greater it grows.

Leonardo speaks of time: “O time, devourer of things! Transforming them within you, you give new and different dwellings to the lives you have stolen.” “O time, quick ravisher of created things, how many kings, how many peoples you have destroyed! What transformations of states and conditions have taken place!”

Time affects the work of nature and the work of man differently. What nature produces is always the same in kind. What men produce is forever changing, languages, for example: They “have always been infinitely different and must remain so, because of the innumerable centuries contained in infinite time.”

Leonardo speaks of nothingness. It is distinguished from a vacuum. For a vacuum is divisible to infinity. Nothingness cannot be divided, because it cannot be less than it is. Of this nothingness he says: “It dwells in time, it stretches into the past and the future, it lays claim to all works past and those to come, but possesses nothing of the indivisible.”

In another connection he says: In the realm of nature we find no nothingness, it is impossible and has no being. And yet: “Among the great things around us, the existence of nothingness is the greatest.”

Let us sum up: in his reverence for the visible world Leonardo looks on nature as a secret which reveals itself to the investigator ad infinitum. This reverence finds its fulfillment through the eye, in thinking vision, in the determination to take account of everything that is visible or can be made so. It finds its fulfillment in the transparence of this visible world, in which all phenomena become metaphors and invisible forces become visible.

This view brings with it an infinite delight in appearance, but also an infinite sorrow over the way of the world. “Nature was for many a cruel stepmother and for some a kindly mother.”

Why is this so? Leonardo provides no answer. Indeed, he seldom raises the question. When he occasionally does, when the tension between the expediency and the inexpedience, the beauty and the ugliness, the kindness and the cruelty of nature demands an interpretation, he utters the immemorial twofold answer as though in passing: “Nature is full of innumerable reasons that have not yet been brought within the range of experience. … Nothing is superfluous and nothing is lacking in any species of animal or in any product of nature.” And as to the forbidding aspects: “The deficiency does not stem from nature but from the means with which she creates,” that is, matter. This, however, is not Leonardo's thought, but a random borrowing from ancient philosophy.

4. What is man's position in the universe? Is man or nature pre-eminent? For Leonardo there is no pre-eminence. As microcosm, man seems to be raised to the level of the totality, as a creative being he seems to outdo creative nature. But he is encompassed by nature, the All, as the great power beside which he is as nothing.

Leonardo sees man as part of nature. But within nature he is a unique being; he is nature, he exists entirely in and through nature, yet he is more than nature, because he is free to rise or fall. Leonardo sees both the greatness and the littleness of man.

“Man is distinguished from the animals, but only in the extraordinary. He is a divine being. For where nature stops creating forms, man begins, with nature's help, to make innumerable forms from the things of nature. For beings whose behavior is as appropriate as that of animals, such forms are not necessary. Consequently the animals are without any such striving.”

But Leonardo warns: “O man, what do you think of your way of being? Are you really as clever as you suppose?” Man is a strangely powerless and powerful being, powerless in the presence of nature as a whole, powerful in respect of himself. That is his way and his hope. “You can have neither a greater nor a smaller dominion than that over yourself.”

But Leonardo saw how many pervert man's potentialities and fail to live up to them. “Few men are displeased with their vices. Many hate their fathers and all those who reprove them for their vices. Neither object lessons nor human counsel make any impression on them.” In congratulating his brother on the birth of a son, Leonardo went so far as to write: “You were glad to have created an active enemy, who will strive for freedom with all his might, and find it only with your death.”

Utterly contemptible are “crude men with an evil way of life. They do not deserve so magnificent an instrument as the human body, but only a bag that takes in and excretes food. They are only a passage for food, and have nothing in common with the human race but their shape and voice; and in all other respects they are far inferior to animals.”

In view of men's crimes, he adjures them: “If one man be found virtuous and good, do not cast him out, but treat him with respect; do not compel him to seek refuge from your persecutions in deserts, caves, and other lonely places. If such a man be found, show him honor; for such men are like gods on earth for us.”

5. Death comes to all living things. Man alone knows this and bears death in mind. In his affirmation of life, Leonardo is always aware of death.

One animal lives by the death of another. Why is this so? “Delighting in the creation of ever new lives and forms … nature creates far more swiftly than time destroys. Therefore she has decreed that many animals should serve as food for others. But since this is not enough, she often sends down pestilential vapors on accumulations and herds of animals, and above all on human beings who increase very rapidly. … Thus for the sake of constant increase, the earth strives to lose a part of its life.”

This tendency, objectively a necessary factor in life, has its subjective counterpart in a death urge. “As a moth is drawn to light, so man always hopes and yearns to find his way back to primal chaos. With unflagging desire he eagerly looks forward to each new spring, each new summer, the new months, the new years, thinking that the things he longs for come too slowly, and unaware that he is longing for his dissolution. But this ardent desire is the quintessential spirit of the elements, which, imprisoned in the life of the human body, always desires to return to its source.”

The cosmic urge of the elements is present in the drives of men.

But what reality has death? It is and it is not. Its being is similar to that of sleep. “What is it that men passionately yearn for, but do not know when they possess it? It is sleep.” “Every evil leaves affliction in the memory, except the greatest evil, namely death, and this extinguishes memory along with life.”

Knowing the law of nature, Leonardo lived serenely and loved life. “Expecting to learn how to live, I learned how to die.” “As a day well spent brings happy sleep, so a life well spent brings happy death.”

Even the thought of an egg being eaten reminds him of the invaluable gift of life: “Ah, to how many it will not be given to be born.” When ambitious men foolishly “content themselves neither with the gift of life nor with the beauty of the world,” that is their punishment for embittering their own lives.

6. What is the position of Leonardo's thinking in the history of philosophy?

Leonardo does not construct a system of metaphysics. If we were to derive a system from his thoughts, it might be roughly as follows: in the creation of the world art and knowledge were one. God created everything in forms, and ordered everything according to measure, number, and weight. Mathematics is at the source of creation, the Creator is a mathematician, but this in the widest sense, encompassing all formation, order, and law.

Cognitive man, the microcosm, repeats Creation in his cognition and carries it on in his own creation. His knowledge is itself form, it copies the forms of nature and brings forth new forms. Thus the work of the artist is not naturalistic reproduction of the contingent, but the form in which nature lives and is apprehended in its essence. The man who creates through knowledge penetrates to the foundation of the world, the revelation of which is essentially one with artistic creation.

Because Leonardo perceives the source in the manifold phenomena of the world, two things which are otherwise separate remain one in Leonardo's vision. From the standpoint of specialized, exact science or of art for art's sake, confusion reigns in Leonardo. For him morphological observation is inseparable from causal interpretation, mathematical mechanics from meaning and purpose, and beauty from symbolism. Thus every work becomes at once knowledge of an object, expression of a mood, and, by the infinite resonance of its meaning, metaphor.

But what of Leonardo's Christian paintings? The subject matter of his masterpieces, The Last Supper, the sketch for the Adoration of the Kings, the Virgin of the Grotto, the Madonna and Child with St. Anne, is Christian. Of this Leonardo, who seems to reflect on everything, does not say a word. To paint Christian subjects was as natural as the performance of Church rites at birth and death. Actually, Leonardo employed these themes as vehicles: for the expression of motherly love, feminine beatitude, the impact of emotion on men of different character, and as an excuse for a composition based on gestures of adoration.

In Leonardo many traditional philosophical ideas meet. The sources of his ideas have been studied in detail.

Western metaphysics can be broken down into several great historical types. In Leonardo we find elements of the Aristotelian cosmos with its degrees of motion, more of the Stoic cosmos as a rational totality of forces, a few ideas from the materialistic philosophy of Democritus and Lucretius, next to nothing of the Platonic division between world and transcendence, and very little of the Neoplatonic spirit, except in so far as it is implicit in the Stoic conception of the animated world.

Leonardo lived in no system, but used them all only as means of expression. He did not subsume phenomena under categories already presumed to be known, but investigated them and allowed them to open up new realms of knowledge. This fundamental attitude—to accept no knowledge as complete but restlessly to pursue every particular reality; to delight in observation, and look upon all things with serenity—this reverence for the visible world is what distinguishes Leonardo from all ancient and Christian metaphysicians.

III THE LIFE OF THE PAINTER AS A COGNITIVE FORM OF BEING

Leonardo was conscious of his life as a magnificent form of being.

1. Many writers have called attention to the sociological situation of the artist in the Renaissance. Like other men, the artist was dependent, in so far as he required the support of the powerful, on princes, cities, and the Church. But an able artist was sought after. He alone possessed freedom along with his dependence, for he was at home everywhere and able and willing to move about. He was in a position to see and know the world. His arts were his letters of nobility. He acquired proficiency in science, invention, building, the arts, and personal skills, from riding to the playing of musical instruments. He built canals and war machines, planned ingenious festivities, created works of art which brought world fame to his city as well as himself. He became l'uomo universale. He lived as a prince among princes.

This was true of Leonardo. In applying for a post, he was obliged to laud his abilities, as in his famous letter to Lodovico il Moro in 1482. In his nine points, the greatest stress is laid on his accomplishments as a military engineer; only one point has to do with his peacetime accomplishments as an architect, hydraulic engineer, sculptor, and painter. To be sure, he too suffered great disappointments. “The Medici,” he notes, “made me great and ruined me.” He served Lodovico il Moro for sixteen years. When this prince was overthrown by the French, Leonardo wrote: “The Duke has lost his city, his property, and his freedom, he has completed none of his works.” A few years later he went to work for Lodovico's adversary, the King of France; in between he served Cesare Borgia and his native city of Florence. Leonardo gained and maintained his freedom.

Leonardo conceived the artist's sovereign way of life as an ideal, which he also fulfilled. He made great demands on the profession of painter, and formulated them more fully and clearly than anyone else. He planned literary works which would instruct painters in the knowledge that concerned them. This knowledge was by its very nature encyclopedic. If these books had been finished, they would have amounted to a new form of medieval speculum, a genre with which he was thoroughly familiar. But he conceived his encyclopedia in an entirely different and new sense, as a tool for painters considered as men of all-embracing science, and as a manual of original scientific investigation, to which he wished to lead painters. The painter's way of life was his great theme.

2. The true painter is universal. He “who does not take equal pleasure in all the things that are contained in painting is not universal.” He “who is not a universal master, able to depict every kind and quality of form, cannot be a good painter.” There is “no greatness in studying a single theme all one's life and achieving a certain perfection in it. Since painting embraces all the things that nature produces, all those which result from the fortuitous action of man, and finally, everything that can be understood with the eye,” “that man is a wretched master who is proficient at making only one figure,” “a nude, a head, garments, animals, landscapes.”

Universal painting of this kind is based on knowledge. Practice without knowledge is like navigation without helm or compass. Consequently, “practice should be based on sound theory,” and the painter should “study with rule and order.” “For one who knows it is easy to become universal.”

Leonardo praises activity as such. “You must exert yourself,” “the mind languishes without exercise.” “Fortune helps only those who bestir themselves.” But this activity must have its measure in the man. “Man deserves praise or blame only for the things which it is in his power to do or leave undone.” “Do not strive for the impossible.”

Activity is the main thing. “Death rather than weariness.” “A life well spent is long.” “He who is fastened to a star does not turn back.”

But it is love, and not mere empty industry and conscientiousness, that permits a man to soar in his action. “To learn to know the admirable things of nature, that is the way to love the architect, that great inventor. Great love springs from great knowledge of the beloved object.” The lover is moved by the thing he loves, but if “what he loves is base, the lover becomes base.” False love leads downward. “In the beginning one resists more easily than at the end.” “Intellectual passion drives out sensuality.”

Neither knowledge, nor a skillful hand, nor industry, nor universality, nor love, can produce anything by itself. The essential is imagination, which is always original. “Never should a painter imitate the manner of another; for in respect of art he will be termed not a child but a grandchild of nature.”

Strange phenomena suggest to Leonardo how inventiveness can be stimulated: “If you look at walls spotted with all sorts of stains or at rocks of various composition, or at ashes in the fire, or at clouds or mud, you will discover wonderful inventions in them, landscapes and fantastic things such as devils, human heads, animals, battles, cliffs, oceans, clouds, or woods.” But he goes on at once to warn the reader: this vision is still nothing. “It is exactly as with the sound of bells, in whose ringing you may introduce any name or word you can imagine. But although such stains give you inventions, they do not teach you to complete anything whatsoever.”

Work on the basis of knowledge, and the judgment which precedes each work and makes critical decisions—these two make possible the activity of the painter whose imagination has given him forms.

3. How does a painter live with other men? He will inevitably suffer: “No perfect talent without great suffering.” He should learn “patience in the presence of great vexations.” If the vexations increase, you must multiply your patience, “just as you put on more clothes when the cold becomes more intense. Then vexations will no longer hurt you.”

A painter needs solitude. Then he can consider undisturbed what he sees and consult with himself; thus he becomes “like a mirror.” “If you are all alone, you belong entirely to yourself. But if you are with even one companion, you belong only half to yourself.”

But such solitude, necessary for reflection and inspiration, does not occupy all the painter's time. Leonardo insists on companionship: it is better to draw in the company of others than alone. Rivalry acts as a spur. You learn from those who work more ably than you. Praise encourages. Since we delude ourselves so readily about our own accomplishments, it is good “to listen willingly to what your adversaries say of your work; hate is more powerful than love.” Thus we should not refuse to hear the opinion of anyone.

In friendship Leonardo demands magnanimity: “Blame your friend privately, praise him in public.” But emulation should never cease: “Pitiful is the pupil who does not outdo his master.”

4. Leonardo's high ideal of the painter's existence is based on the importance of painting as an instrument of knowledge. In the manner of the traditional disputes about the relative merits of the active and the contemplative life, or of the humanities and medicine, Leonardo compares painting and poetry and accords the higher rank to painting.

Poetry is painting that is heard and not seen, painting is poetry that is seen. Poetry is blind painting, painting is mute poetry. Poetry treats of moral philosophy, painting encompasses natural philosophy. Poetry describes the activities of the mind, painting shows what the mind effects by movements of the body.

The pre-eminence of painting is evident for Leonardo. Painting is as far removed from poetry as the body from its shadow. Painting has the thing itself, it presents the works of nature to the intellect and feeling; poetry has only words. Hence if poetry is to convey an impression of reality, it must be complemented by the imagination.

Only painting can fully represent reality. It “extends to the surfaces, colors, and figures of all the things created by nature.” Thought, to be sure, penetrates to the inside of bodies, conceives their intrinsic forces. But it is not saturated with such truth as the painter brings forth. For in his own being he apprehends the first truth of bodies. The eye is less deluded than the intellect.

Painting is science, it is the source of sciences, and it goes beyond science.

It is based on geometry and arithmetic. It invented perspective. Through perspective it instructs astronomers, it shows geometry how to form figures, instructs engineers and builders of machines.

It studies bodies according to their structure and movement, so becoming anatomy, zoology, botany, and geology. It “concerns itself with works human and divine, all those which are contained by a surface, that is, contours of their own.”

It invented the signs used in writing.

It is more than a doctrine. It is an art. It not only studies but also produces. The scope of what the painter brings to knowledge by making it visible is all-embracing. “The painter is master over the worlds of reality and dream.” “He outdoes nature. For the productions of nature are finite in number, but the works which the eye commands the hand to execute are infinite, as the painter shows by inventing innumerable forms of animals, shrubs, trees, and situations.” “If a painter wishes to perceive beauties that move him to love, he is lord and God over them. If he yearns for inhabited regions or deserts, if he wishes to see valleys, or large expanses from mountain peaks, or the horizon of the sea, he has all these at his command. Everything there is in the universe, in reality or in the imagination—all this he has first in his mind and then in his hands.”

Painting is more satisfying, because it shows the exact portrait of the object that is loved; it arouses the sense more easily than poetry.

Painting is communicable to all; its language is equally comprehensible to the Greek, Latin, or German, while poetry is bound up with a particular language.

Painting is a more noble art; ability to paint cannot be acquired by all. Its works cannot be reproduced in many copies like books. Essentially literature garners up wares that have been made by other artisans. When a poet tries to speak of astrology, he steals from the astrologer, of philosophy, from the philosopher.

If some of Leonardo's formulations verge on the absurd, it is only because he allowed the richness of the visual world, which he actively knew, to blunt his feeling for the rest.

As a result he himself was unaware of the value of his writing, though he composed the clearest expositions and magnificent poetic passages. According to Goethe, it was Leonardo's lucid and rational visual view of the world that enabled him to paint also with words, setting before our eyes the violent movements of complicated happenings such as battles or storms.

It also followed that he did not revise his written texts, that he preserved all the stages of expression, from the haphazard and inane to the perfect formulation, nowhere striving for perfection; that he made no attempt at order or disciplined construction and did not go beyond the spontaneity of immediate diction.

Leonardo did not despise poetry, he merely placed it in a lower rank than painting. But a very different tone becomes audible in his angry attack on men of letters. Their high claims are absurd, their criticism infuriating. They find fault with inventors, because they themselves have never succeeded in inventing anything. They cite the authority of writers for their opinions, exercising not so much their intelligence as their memory. They deck themselves out with other people's accomplishments. They call painting a mechanical art. They look down on painters, because they are not scholars. But anyone who looks down on painting loves neither philosophy nor nature.

Leonardo carried on a memorable struggle. The wordless world of the eye, painting as a language of the visible, combats intellectual discourse as the abstract language of writing and speech. Experience is opposed to book learning. Active creation in concrete works is opposed to the derived character of the language of words. In his whole being, this man who gained knowledge through action, who created with his hands, despised the existence of the writer alienated from life.

Most painters do not write. Their lives are not long enough to complete their own work. And painting itself does not disclose itself and its ultimate intention in words. “Like the excellent works of nature, painting ennobles itself by its own resources, without the help of any other tongue.”

But Leonardo took it upon himself to write. He believed that in general writers “can gain no insight into the science of painting,” but that his own precepts were different, since they were “derived not so much from the words of others as from experience.”

IV CHARACTERIZATION OF LEONARDO

We have considered Leonardo's method (to penetrate to the spirit within the body by means of the eye and hand), his view of the world (the cosmos of forces), and his form of existence (the life of the painter, who gains knowledge through vision). Now let us go back to our initial question: in what sense was Leonardo a philosopher?

1. If Leonardo is taken as one of the founders of modern mathematical science, it is an easy matter to refute this contention and so seemingly discredit the whole of his scientific endeavor. If Leonardo is taken as a universal modern scientist, it can be shown that admirable as his discoveries in anatomy, geology, botany may be, they have been superseded in practice and are of purely historical interest. If he is taken as a painter, his greatness is unassailable, but here again it may be argued that his work itself is fragmentary, and that its author is more of a celebrity than a continuously active stimulus. Thus he is known chiefly as a historical figure, as one of the pioneers of classical art, as merely one—and not necessarily the greatest—among many great artists.

But in one respect we discern a unique greatness which is more than historical: in the being itself, who was the source of all this scientific and artistic creation and whom it served: the personal embodiment of a philosophical existence and knowledge of the world.

Here the scientist, the technician, the artist are one, and in this unity no one factor is dominant. It is not Leonardo's intention but the interest of posterity which singles out one as the essential—usually the artist. We may call this unity Leonardo the philosopher, if by philosophy we mean not a category of science, not a doctrine, but a universal knowledge which gains awareness of itself as a whole and takes itself in hand, hence as a form of human existence which embraces knowledge. In art, science, painting, architecture, and at the same time above them is situated a spiritual area, into which they all lead; they are not self-sufficient. Such a philosophy gains historical weight where it becomes communicable as a whole in existence, work, and thought. Leonardo is a philosopher in the same sense as Goethe.

There are several poet philosophers. Leonardo was the only artist philosopher of a high order. In him art became the organon of philosophy, because he not only carried on the activity of the artist as an instrument of knowledge but also made it an object of reflection. This distinguishes him essentially from such great metaphysical artists as Michelangelo and Rembrandt. But he is also distinguished from those who are explicitly termed philosophers by his method of philosophizing. Because art was the organon of his philosophy, Leonardo's philosophical medium was not so much rational logic and systematic conceptual construction as a concrete philosophical logic and a conscious way of life.

What Leonardo was and did demonstrates: First, that philosophy remains poor and incomplete without something that is more than thought, that first gives body to ideas, something that is created in art and poetry, and that this must become an organon of philosophical insight. Secondly: Leonardo's life and work bear witness to the authority which everywhere, and also in art, sees the alternative and decides between good and evil, true and false, substantial and empty, salutary and unsalutary. For art, like all other realizations, is an element of believing existence and as such subject to this Platonic judgment. What we speak of here is something fundamentally different from what connoisseurs of art call quality. For spiritual creation can be Luciferian, high in “quality” and worthless in its enchantment, beguiling men into irresponsible aesthetic enjoyment, admirable and terrifying.

2. Where unity of the whole becomes intellectual reality and is aware of itself as such, philosophy is present. Great philosophers of the nineteenth century believed the division of spiritual life into provinces such as art, literature, science, and religion to be fundamental. The tangible existence of works of art, works of literature, scientific findings, religions, made this classification convincing, and it became so deeply ingrained by habit that we have great difficulty in shaking it off.

Applied to Leonardo, such a view carries the following implications: He is famous for his paintings, much less for his scarcely known literary work, still less for his scientific findings, which seem to be mere curiosities, amazing us by their anticipation of future discoveries. From this standpoint, his science appears to be a mere secondary activity, without any real relation to his art. We can be interested in one without necessarily being interested in the other. Leonardo's many-sideness is not the many-sideness of a unity that lies in the nature of things, but the regrettable dispersion of an overversatile talent.

A proper appreciation of Leonardo is possible only if we understand the limited bearing of such a division of cultural spheres into art, literature, science, and technology. Then his painting, writing, and scientific endeavor point to a whole, which precedes all divisions and cannot be subsumed under them. In an existence such as his all the varied activities and states of being spring from a center and are directed toward a goal. This existence was a mode of being, of seeing, of loving, of experiencing sadness or joy, of perceiving reality and objectively communicating this perception. It is the unity which this man seeks as a living reality, which he himself becomes and represents.

When we try to grasp this unity, the historical reality that is present in this one man coincides with the objective problem that we are trying to clarify by a universal concept. One cannot understand a historical man on the strength of a concept. But we can attempt to know the reality in accordance with its universal principle.

On this point, I wish to say only the following: all these separate fields tend toward futility when they isolate themselves, when specialization becomes separation, when correctness within each autonomous field is taken for the truth, when each field, setting itself up as an absolute, lays claim to dominance. Then science, art, religion, love, politics, economics, each proclaims its independent law as an ultimate, against which there is no appeal. But the higher authority, which springs from the Encompassing, which imposes its measures on each of these domains and at the same time enables it to remain meaningful and in contact with the source, is not just another particular; it cannot be apprehended directly and objectively, but only by way of those separate fields. All of them derive their meaning from the source, which is one.

Yet the fulfillment of this totality is impossible for men. The more powerfully and profoundly it strives for expression in a human being, the more drastically it is bound to fail, and this failure itself manifests the truth. But this never happens without ambiguity; it cannot be compellingly demonstrated.

3. Leonardo has been much criticized. It has been said that his whole existence was contingent subjectivity; that he failed to keep his promises and disappointed his employers; that his work was at the mercy of moods; that he kept turning to new occupations and never finished anything; that his scientific methods were without logical structure, hence subjective and contingent like everything else about him.

The facts on which these reproaches are based are incontestable. But the way in which they are stated and interpreted in reference to Leonardo's character strikes me as utterly mistaken.

This much is certain: Leonardo's work is fragmentary. There are few finished works of art from his hand, and it is doubted whether even these were really completed. He was an indefatigable worker—witness the abundance of manuscripts and drawings he left behind him. But he never completed a book, neither the anatomy which was far advanced, including hundreds of drawings, nor the projected work on geology and cosmography, nor the encyclopedia for artists, which he seems to have planned. The Treatise on Painting was compiled after his death and the title did not originate with Leonardo. As for the countless projects of buildings, city plans, canalization, military engines, and contrivances of all sorts, it is certain that few if any were ever executed.

The question is: why did he leave his work unfinished?

The explanation that his moods led him to disperse himself is refuted by the persistence and meticulousness shown in the work he actually performed. If he nevertheless left his work unfinished, it was because the attraction of other, related tasks made him set aside the work in hand, though always meaning to go back to it. He considered his work as a totality and held that everything he did must be subordinated to that totality. But the whole was so enormous that it could not have been fitted into the life of any one man.

This whole was knowledge of the world. But this was a new kind of knowledge which by its very nature could not be completed: Leonardo's aim was not a rational schema of the universe, but knowledge growing from concrete perception. This was the modern scientific attitude, as opposed to all dogmatism. Consequently, every field demanded specialization. In everything he undertook Leonardo became a specialist. But how could any one man complete the task that has occupied the Western mind for centuries and is still far from concluded? He could not content himself with any special field, because what concerned him was the world as a whole; but only specialization offered real access to the whole. His superhuman effort to specialize in everything in a single lifetime was doomed to failure. He would fling himself wholeheartedly into a single field and soon set it aside, going on to something else but meaning to go back.

Another reason why Leonardo could not achieve total knowledge of the world by his innumerable specialized endeavors was that empirical reality was not enough for him. He was captivated by the spiritual content of all reality. In order to manifest this content, it was necessary to design images in his mind, which his hand would fashion into reality in works of art. But since the spiritual can never be fully represented and since the idea is in advance of every work, no work of art can be adequate.

Filled with the striving for totality, Leonardo was assailed by new images demanding to be set down and by ideas springing from observation and clamoring to be formulated. Nearly always he saw an obscure relationship between these images and ideas and his total conception of the world; this meant that he had to take them up, that he could not abandon them. As a result, Leonardo's work, which achieved world fame on the basis of a few relatively completed examples, grew, like his entire visual thinking, from a vast field of project and experiment, without definite goal. His endeavor was a “working in prefigurations,” as Gantner convincingly called it. Only in small part were these prefigurations projects that would attain their goal as finished works of art. They were not, like the sketches of other great artists, disciplined by their aims. Rather, they were a perpetual beginning, toward the translation into images of all things without exception. This accounts for the many projects which by their very nature defied completion, and for his daring attempts to make every mode of the invisible visible, often at the cost of failure. He did not see such failure as genuine failure, for he was convinced that everything could be made visible.

The fragmentary nature of his work with its abundance of projects in statu nascendi resulted also from the universality which finds all finished work inadequate. For in the context of a striving for total knowledge, which anticipates its fulfillment in prefigurations, the fully elaborated work, along with the satisfaction it confers, implies a limitation. Leonardo strove for perfection, because without such a striving everything would blur—in his art by persistent verification and in his scientific investigation by the closest attention to detail. But only for a time. He could not, and had no desire to, accept limitations. He desired perfection in every particular, but was unwilling to lose himself in the process of attaining it. In a few great works he became a great artist, and in his scientific investigation he became a specialist. But he wanted everything to serve the one totality, which was always present to his mind and which made every shortcoming a hopeful shortcoming.

Wishing to build an edifice superhuman as a whole but preserving human proportions in every particular, Leonardo inevitably left behind him—apart from the few magnificent pictures, which anyone else would have regarded as perfect, and a few fully realized scientific experiments—a mass of painstakingly gathered but unused building materials.

In working out his ideas, in improving and correcting, in moving toward a purer truth, Leonardo was not able to preserve his sure, unique stamp (as (Rembrandt did in every one of his drawings and engravings); he was unable to sustain his highest level in every one of his thoughts (as Pascal, Leibnitz, or Kant did in every note they jotted down).

But where he attained his best it is inimitable. In copies, in the work of his imitators, the essential is lost in favor of a beauty, an enchanting form perhaps, a deceptive perfection which, however, lack the uniqueness of vision, the reticence even in the smile, the indirectness of that which is made visible.

4. Leonardo has also been accused of other grave shortcomings. His life lacked roots. An illegitimate child, he was committed to neither family, home, nor country; he was a cosmopolitan, who lived where he was paid to live, without allegiance or loyalty. It is pointed out that he did not marry and had no friends, but only patrons, pupils, and admirers; that he took no interest in human institutions, in law, politics, or history, and identified himself with no country.

Consequently, it is maintained, he had no sense of responsibility, he worked unceasingly at one thing or another, but never acted; his life was spent in irresponsible contemplation, bringing forth pictures of everything the world disclosed to him; he never attempted to change the world, never felt impelled to play a part.

It has also been said that the problems of ethics and religion interested him no more than those of politics; that his occasional ironies about the errors in the Holy Scriptures, the sterility of syllogistics, and about monks were the typical ramblings of a skeptic, with which he tried to justify his lack of faith and will, his inability to call evil by its name and combat it.

There is no unequivocal evidence to support these accusations. Leonardo's nomadic life, his exclusive concentration on his work, his indifference to politics are subject to varying interpretations.

He did not take a hand in the affairs of the world. He had no inclination to seek a position of power. Ambition, jealousy, desire for success seem to have been alien to him. He cared nothing for public life. What we know of his private life argues fairness, magnanimity, and simplicity.

Despite his many acquaintances and admirers, despite all those who cared for him and loved him, he was solitary all his life, but we have no indication that he suffered from his solitude. Leonardo relied on himself, without protection or desire to be protected. His self-reliance was unshakable.

His mind was too clear to be overrun by hidden, uncontrolled forces within him. For all his extraordinary qualities, he was without extravagance; for all his depth, we discern no eruption of hidden powers. Everything we know of him gives an impression of moderation and rationality. His existence was not grounded in any profound inner upheaval or consuming passion. What we see, rather, is patience, serenity, and an unwavering love of the glories of the world.

But his serenity was conferred by an enormous and unflagging activity. There is no trace of resigned, weakwilled sadness.

Leonardo's loving universality shone like the sun upon all things. But it had one limitation: it was a universality of active vision. His interests could be so universal, because he refused to be limited by identification with any historical action. He engaged in no ideological struggle, neither against the Church, nor against any political powers, nor any faith. He himself followed no system of philosophical ideas, but lived with an infinite openness to everything that can happen.

Leonardo was aware of the advantage of such contemplation of all things: “With the help of ideas we are universal and dwell simultaneously in all places; the will puts us in a single place and settles us there.”

Nietzsche admired this universal impartiality. Leonardo, he wrote, “was supra-Christian in scope; he knew the Orient both inwardly and outwardly; there is in him a more-than-European quality, such as distinguishes every man who has seen too wide a range of good and evil things.” Nietzsche counts him among the “magically unfathomable and inconceivable men, those enigmatic individuals who are predestined to victory and seduction.” This strange characterization becomes valid only if reason itself, clarity itself, the pure love of the independent man, is regarded as enigmatic.

Leonardo's attitude toward Christianity was the unmilitant attitude of a man who does not know and is not touched. To him it was not a problem. He seldom spoke of it. He refuted the story of the flood, but on another occasion he wrote: “Do not lay hands on the crowned books [the Bible], for they are of supreme truth.” He was said to have provided that the Church rites should be performed at his death, remembered the hospitals for the poor in his will, and left wax candles to various churches. Yet these reports are questionable, suggesting an ecclesiastical mind rather than Leonardo's. Leonardo lived with the transcendence of the spiritual; he speaks of God, but the God he speaks of is not the revealed God of the Bible. He does not tell us whether or not he prayed, and if so, under what circumstances. His painting of Christian subjects is no indication of Christianity. He lived in the perfect freedom conferred by the religious indifference that was possible before the Reformation.

Thus Leonardo was impervious to human desires and passions, and to the consolations of faith. But one thing remains. Though he was without ambition and uninterested in honors during his lifetime, he clearly expressed his desire for posthumous fame. It was a spur to unflagging activity. “One who spends his life without fame, leaves no more trace on earth than smoke in the air and foam on the water.” “Oh, why do you not create such a work that after death you will be as one wholly alive, instead of sharing even in your lifetime the sleep of the pitiful dead.” And he notes with certainty: “I will endure.”

Here lie his greatest remoteness from Biblical religion and his kinship to antiquity and the Germanic world. The absolute transience even of posthumous fame is forgotten. For him, glory took the place of eternity, which can be known only in radically different dimensions, making an absolute of unceasing activity and leading him to forget that for all its grandeur it is as nothing in the face of transcendence. Here perhaps lies the hidden seed of a sublime inhumanity. And perhaps this accounts for the sudden misgiving which sometimes tempers our enthusiasm for Leonardo and which prevents us from being wholly at one with him.

5. What impression did Leonardo make on those about him? We hear of his physical strength, of his supremely beautiful face, of his winning charm, his ease of manner. We hear of the enormous impression made by his works, which no sooner became known than they were declared to usher in a new epoch in painting.

But in some accounts we sense that he may have struck certain observers as personally forbidding, lacking in warmth—and precisely because he was without passion or anger or immoderation, vices which create a bond of common weakness and make us prize those who overcome them.

Even today the general impression made by Leonardo has this sobering quality. This man—who needed no other, who in his quest for knowledge relied wholly on himself, who went through the world immured in solitude, without communication of the kind which enables a man to come to himself in relation to another self—commands our respect but does not draw us to him. His winning charm has often been mentioned. But on many occasions he seems to have made another impression, because perhaps he was lacking in that truly human charm, the weakness of the great man who for all his greatness stands in need of others.

Michelangelo and Raphael were idolized, whereas Leonardo, though welcomed by the King of France and various aristocrats, was not generally sought after.

When Leonardo and Michelangelo were both in Florence, the young men flocked to the much younger Michelangelo. When once Michelangelo in a group of painters shouted at Leonardo: “You who were never able to cast an equestrian statue, and the Milanese, those blockheads, had faith in you”—Leonardo said nothing and only blushed. He always maintained his distinguished bearing, while Michelangelo allowed his emotions to carry him away.

Michelangelo created figures which surpass Leonardo by the passion which informs them and the magnificence of their form. They reveal a world in upheaval, a despair that impelled to transcendence; Biblical faith became a new reality.

Leonardo and Michelangelo are two worlds between which there is little contact: Leonardo a cosmopolitan, Michelangelo a patriot; Leonardo serene and balanced, governed by moderating reason, Michelangelo beset by confused emotions from which he heroically rises; Leonardo controlling himself, calm amid passion, looking upon things and himself with detachment, Michelangelo given to shattering passions, unrestrained in his despair.

Leonardo produced unforgettable figures in the lucidity of reason; he reveals the mystery of reason itself, which seldom seizes upon things directly and is hard to understand in the depth of its lucidity. Michelangelo's creations, products of upheaval and eruption, carry infinite truth, and affect us in a different way; they are more torturing and more moving, more disturbing and more charged with memory.

Leonardo seems to live in an area of peace, unchanging amid happiness and grief; Michelangelo seems to reconquer himself in an area of continual crises, in gigantic oscillations between dejection and supreme exaltation.

Leonardo seems to contemplate the world of extreme human possibilities as a mere aggregate of natural phenomena; Michelangelo is part of it.

6. Those who meet with Leonardo are called upon to hear his appeal. Leonardo's mere fame is conventional. As long as we look on artists as a large group of men, all of whom have done good things in their way, we shall perhaps be dealing with art, but not with what speaks or fails to speak through it. Only if we feel the radical difference between mere art and art as an organon, shall we hear that appeal and be impelled to respond with our inner man from out of the Encompassing, whence words and images come to us only because we ourselves are in process of becoming. What do we hear through Leonardo?

The mute, unresponsive world demands to be known and loved. Leonardo's relentless activity pursued no other purpose than to see the world and to mirror it in the mind by means of the imagination.

There are few men who all through their lives are wanderers, seemingly detached from other men, wishing only to see the world and to communicate what they have seen. These men do for us what we can do only inadequately for ourselves. Constantly discovering and disclosing, they perceive with their whole being what we others learn to see through them. The fact that they do our work for us and allow us to look on to the best of our ability, gives them the privilege of standing aside while other men act and struggle and change the world of human affairs. Theirs is a different struggle, an intellectual struggle to perceive the eternal essences in the surface and appearance of the world.

And there is something more. We are fortunate in being able to meet in Leonardo an independent man, who, rising above society and history, neglecting both, lived in harmony with infinite nature through his vision of its revelations.

Our pleasure in accepting the gift of his manner of seeing and investigating, of his existence, does not imply that we ourselves should follow him in his way of life or mode of philosophizing.