The Science of Leonardo: Inside the Mind of the Great Genius of the Renaissance

by Fritjof Capra

  Art historians believe that Leonardo may have let Ambrogio Predis paint large parts of the London version. This seems to be confirmed by recent analyses of the rocks and plants in the painting’s background. Scientists have noted that both the geological and botanical details in the London version are significantly inferior to those in the painting in the Louvre. It is highly unlikely that they were painted by Leonardo.48

  The confraternity may have had good reasons to be dissatisfied with the Virgin of the Rocks, but in the botteghe and intellectual circles of Milan, Leonardo’s masterpiece caused a sensation. The artist’s low tones of olive green and gray were in stark contrast to the bright colors of the quattrocento, and the Milanese could not have failed to notice the subtle gradations of light and shade, nor the powerful effect of the surrounding grotto. As Kenneth Clark describes it, “Like deep notes in the accompaniment of a serious theme, the rocks in the background sustain the composition and give it the resonance of a cathedral.”49

  SYSTEMATIC STUDIES

  In 1484, while Leonardo was working on Virgin of the Rocks, Milan was hit by the plague. The epidemic raged on for a full two years and would kill close to one-third of the population. Leonardo, recognizing the critical role of poor sanitation in the spread of the disease, responded with a proposal for a new city design that was far ahead of its time, as I discussed earlier.50 But it was ignored by the Sforzas. This renewed failure to get the court’s attention with his ideas brought Leonardo face-to-face with the huge handicap of his upbringing: his lack of a formal education. He was attempting to be accepted as an intellectual in a culture that was in close contact with the leading universities, a culture dominated by the written word, in which Latin was used almost exclusively. Being an “unlettered man,” Leonardo was not only ignorant of Latin but, even in his native Tuscan, did not have the abstract vocabulary necessary for precise and elegant formulations of his theories.

  Leonardo tackled this seemingly insurmountable problem in his methodical, sustained, and uncompromising way. “In his mid-thirties and practically without any knowledge of Latin,” writes historian of science Domenico Laurenza, “he embarks on an intense and in some ways obsessive program of self-education. The years between 1483 and 1489 are dedicated largely to this obstinate attempt of cultural emancipation.”51

  Leonardo began his extensive program of self-education with a systematic attempt to enlarge his vocabulary. This was the time when Italian as a literary language was just beginning to emerge from Florentine Tuscan. Dante, Petrarch, and Boccaccio had all written in Tuscan, but the orthography had not yet been codified; grammars and dictionaries had not been published. The new vernacular was beginning to replace Latin as a written language, especially in texts about art and technology, and in the process it became enriched by a vast assimilation of Latin words. Leonardo was familiar with compilations of these vocaboli latini (new Italian words derived from Latin), and he laboriously copied them into his Notebooks.52 In his earliest manuscript, the Codex Trivulzianus, page after page is filled with lists of such words. In fact, Leonardo referred to this Notebook as “my book of words.”53

  As he turned to the written word, Leonardo also began to build up a personal library. In Florence he had read some literature and poetry, but had not studied scientific texts. He had acquired a rudimentary scientific education by studying the drawings of architects and engineers, and by having discussions with various experts in the bottega.54 When he left Florence, he made a list of the things he wanted to take with him to Milan.55 This list did not contain a single book.

  A few months after his arrival in Milan, Leonardo listed five books in his possession; by 1490 he had added 35 new titles, and from then on the number of books in his library increased steadily, reaching 116 at its peak in 1505. In addition to the volumes he owned, Leonardo regularly borrowed books, so that his full personal library would have included about 200 books—a substantial library even for a Renaissance scholar.56

  The subject matter of these books was diverse.57 Over half of them dealt with scientific and philosophical matters. They included books on mathematics, astronomy, anatomy and medicine, natural history, geography, and geology as well as architecture and military science. Another 30 or 40 were literary books. A dozen or so contained religious stories, which Leonardo would have consulted when he painted religious subjects.

  These books provide ample evidence that Leonardo, during the last two decades of the fifteenth century, not only honed his language skills but was well versed in the major fields of knowledge of his time. As with everything he tackled, he would investigate several areas simultaneously while being involved in various artistic projects. He always looked for patterns that would interconnect observations from different disciplines; his mind seemed to work best when it was occupied with multiple projects.

  The beginning of Leonardo’s systematic studies in 1484, not surprisingly, coincides with the first entries in his Notebooks. Once he embarked on his interdisciplinary program of research, he regularly recorded all new ideas and observations. Now in his mid-thirties, it was the time when he deepened his theoretical investigations beyond his needs as an artist and inventor. For example, when he studied the nature of light and shadow, he did so at first to develop his theory of painting. But eventually he went much farther. As Kenneth Clark observed,

  He drew [a] long series of diagrams showing the effect of light falling on spheres and cylinders, crossing, reflecting, intersecting with endless variety…. The calculations are so complex and abstruse that we feel in them, almost for the first time, Leonardo’s tendency to pursue research for its own sake, rather than as an aid to his art.58

  While he carried out his investigations of light falling on solid objects, Leonardo also became interested in the physiology of vision, and then went on to study the other senses. His earliest anatomical drawings, based on dissections dating from the late 1480s, are beautiful images of human skulls, all of which reveal the optic nerve and the path of vision.59 These are no longer drawings merely for the benefit of the painter; they are also, and perhaps more important, the first scientific diagrams of Leonardo’s anatomical research.

  In his drawings of machines of that period, too, one can see a definite movement toward exploring deeper theoretical problems. (As Domenico Laurenza has pointed out, Leonardo seems to have revised his early technical drawings around 1490 by adding various theoretical comments.)60 What one sees in all these examples—from optics to anatomy and engineering—is the emergence of Leonardo the scientist.

  GRADUAL ACCEPTANCE AT COURT

  After the devastation of the plague, Milan’s citizens emerged with a new optimism and sense of excitement encouraged by the lavish spending of the aristocracy. In large parts of the city, houses were remodeled, new squares and avenues were built, and in 1487 a competition was held to design a tiburio (a central tower above the cross of the transepts) for the huge Gothic cathedral, which attracted architects from all over Italy. Caught up in the general enthusiasm, Leonardo became deeply interested in architecture during those years and participated in the competition for the tiburio, together with Donato Bramante, Francesco di Giorgio, and other renowned architects.

  The project was quite difficult, since the high Gothic tower would have to be balanced on four slim pillars, and the existing parts of the cathedral already had structural problems. Leonardo examined all aspects of the cathedral and sketched a variety of solutions before settling on a design and producing a wooden model.61 When he submitted his design to the authorities, he sent along an introductory letter, which began with his comparison of the cathedral to a sick organism; himself, the architect, he compared to a skilled doctor.62

  The judges of the competition deliberated for a long time before finally awarding the contract to two Lombard architects in 1490, with the instruction that they produce a model that would be a harmonious blend of the best parts of all the submitted designs. For Leonardo, this turned out to be a very felicitous outcome.
It allowed him to discuss his ideas about the tiburio, as well as his views on architecture in general, with the other competitors, especially with Bramante and Francesco di Giorgio, the two most famous architects in the group. Both of them would eventually become close friends of Leonardo, would exchange many ideas with him, and would greatly further his career during those years when he began to develop his theories.

  His friendship with Bramante, in particular, was very advantageous for Leonardo. Born near Urbino, Bramante had come to Milan a few years earlier and had already gained the respect of the Sforzas when they met. The two artists had much in common.63 Both were accomplished painters, were interested in mathematics and engineering, liked to improvise on the lute, and admired the famous architect and intellectual Alberti. Both also came from central Italy and were seeking to establish themselves in this northern city. Bramante, who later would design Saint Peter’s in Rome, was said to be completely free of professional jealousy and likely opened many doors at court for his new friend. Historians of art also believe that Leonardo, with his thorough grasp of the principles of architectural design, had a significant influence on Bramante’s work.64

  In 1488, six years after he first arrived in Milan, Leonardo finally had his breakthrough at the Sforza court. In the wake of the reputation he had gained with the Virgin of the Rocks, and perhaps aided by a recommendation from Bramante, he was asked by Ludovico to paint a portrait of the Moor’s mistress, the young and lovely Cecilia Gallerani. Leonardo painted her holding an ermine, a symbol of purity and moderation which, because of its Greek name, gale, was also a veiled allusion to her name, Gallerani. Lady with an Ermine, as it is called today, was a highly original portrait in which Leonardo invented a new pose, with the model looking over her shoulder with an air of surprise and subdued delight, caused, perhaps, by the unexpected arrival of her lover.65 Her gesture is graceful and elegant, and is echoed in the animal’s twisting movement.

  Ludovico was very pleased with the portrait. Soon after its completion, he asked Leonardo to create a “masque” for a magnificent gala, la festa del paradiso, in celebration of the wedding of the duke’s nephew, Gian Galeazzo, to Isabella of Aragon. At the same time, the Moor fulfilled one of Leonardo’s greatest dreams by awarding him the commission for il cavallo—the giant equestrian statue in honor of Ludovico’s father.66

  Leonardo’s “Masque of the Planets” was the climax of the theatrical performance that took place at the grandiose feast in January 1490. On a giant revolving stage, the signs of the zodiac, illuminated by torches, could be seen behind colored glass, and the seven planets, represented by costumed actors, circled through the heavens accompanied by “marvelous melodies and soft harmonious songs.”67 The Masque was a huge success and made Leonardo famous throughout Italy, even more so than his paintings had done. From that point on he was in great demand at the Sforza court as a brilliant magician of the stage, and was referred to in official documents as painter and “ducal engineer.” At the age of thirty-eight, Leonardo had achieved, at last, the position he had desired when he wrote his memorable letter to the Moor years before.

  FOUR

  A Well-Employed Life

  Beginning in 1490, the whole of Italy experienced several years of peace and political stability, during which its city-states accumulated great wealth. In Milan, palaces were renovated, streets paved, and gardens laid out. There were pageants, costumed tournaments, and a succession of performances in a new theater Ludovico had given the city.

  Leonardo had become the Moor’s favorite court artist. He was given a large space for his workshop and living quarters in the Corte Vecchia, the old ducal palace next to the cathedral, where Ludovico housed important guests. He seemed to have had an entire wing at his disposal, where he designed sets and costumes for festivities, invented mechanical devices, carried out scientific experiments, prepared the molds for the gran cavallo he was creating, and tested his first flying machines. To satisfy the constant demands of the court, he employed several apprentices, assistants, and contracted workers in addition to maintaining a small household of domestic staff.1 The bottega di Leonardo was a very busy place indeed.

  For Leonardo himself, the 1490s were a period of intense creative activity. With two major projects—the equestrian statue and The Last Supper—his artistic career was at its peak, he was consulted repeatedly as an expert on architectural design, and he embarked on extensive and systematic research in mathematics, optics, mechanics, and the theory of human flight.

  NEW FOCUS ON MATHEMATICS

  This phase of intense research was triggered by Leonardo’s introduction to the library of Pavia in the summer of 1490. Ludovico had sent him to Pavia, which belonged to the duchy of Milan, to inspect the work on the city’s cathedral together with the architect Francesco di Giorgio. For Leonardo, the journey was intellectually stimulating and personally rewarding in several ways. During the weeks they spent together, he formed a close friendship with Francesco, who was highly regarded as an architect and engineer and whose treatise on civil and military engineering would greatly influence Leonardo in the coming years.2

  Even more important for Leonardo, however, was his discovery of the magnificent library in the city’s Visconti Castle. Pavia was the seat of one of Europe’s oldest universities and had become a major artistic and intellectual center. The great hall of its library, its walls lined with shelves of manuscripts, was famous among scholars all over Italy.3 Leonardo was overwhelmed at the sight of this immense intellectual treasure. Indeed, he did not return to Milan with Francesco when their work was completed, but stayed in Pavia for another six months to further explore the library.

  While he was immersed in this research, he met Fazio Cardano, a professor of mathematics at the University of Pavia who was a specialist in the “science of perspective,” which in the Renaissance included geometry and geometrical optics.4 Leonardo’s discussions with Cardano and his studies in the library ignited a passion for mathematics, especially geometry, and fueled his subsequent research. Immediately after his return to Milan, he began two new Notebooks, now known as Manuscripts A and C, in which he applied his new knowledge of geometry to a systematic study of perspective and optics as well as to elementary problems involving weights, force, and movement—the branches of mechanics known today as statics, dynamics, and kinematics.

  Leonardo’s research in statics and dynamics was concerned not only with the workings of machines but also, and even more important, with understanding the human body and its movements. For example, he investigated the body’s ability to generate various amounts of force in different positions. One of his key aims was to find out how a human pilot might generate enough force to lift a flying machine off the ground by flapping its mechanical wings.5

  In his studies of machines during that period, Leonardo began to separate individual mechanisms—levers, gears, bearings, couplings, etc.—from the machines in which they were embedded. This conceptual separation did not arise again in engineering until the eighteenth century.6 In fact, Leonardo planned (and may even have written) a treatise on Elements of Machines, perhaps influenced by his discussions with Fazio Cardano of Euclid’s celebrated Elements of Geometry in Pavia.

  Amazingly, in the midst of those years of intensive research, and while his workshop was fully occupied with a stream of orders from the Sforza court, Leonardo also continued his literary self-education. In 1493 he began to study Latin. In a special little Notebook, Manuscript H, he copied passages from a popular book of Latin grammar as well as Latin words from a contemporary vocabulary. It is very touching to see passages in which Leonardo, over forty years old and at the height of his powers and fame, wrote out the same basic conjugations—amo, amas, amat…—schoolboys have to memorize at age thirteen.

  FRIENDSHIP AND BETRAYAL

  In the midst of his studies and experimentation, and his final preparations for the casting of the giant bronze horse, Leonardo received the commission from Ludovico to paint The Last Su
pper—the masterpiece that most would argue stands at the climax of his career as a painter. It was to be a large fresco in the refectory of the Dominican convent of Santa Maria delle Grazie in Milan. The monastery was the Moor’s favorite place of worship; the last meal Jesus shared with his disciples was a traditional subject for decorating convent refectories.

  As always, Leonardo contemplated the subject carefully within its religious, artistic, and architectural context. He made numerous preparatory sketches and completed the painting within two or three years—a relatively short period considering that he had to divide his time between painting in the “Grazie” and working on il cavallo in the Corte Vecchia.

  Leonardo’s Last Supper, generally considered the first painting of the High Renaissance (the period of Italian art between, approximately, 1495 and 1520), is dramatically different from earlier representations of the subject. Indeed, it became famous throughout Europe immediately after its completion and was copied innumerable times. The first highly imaginative feature one notices is the way Leonardo integrated the fresco into the architecture of the refectory. Demonstrating his mastery of geometry, Leonardo contrived a series of visual paradoxes to create an elaborate illusion—a complex perspective that made the room of the Last Supper look like an extension of the refectory itself, in which the monks ate their meals.7

  One consequence of this complex perspective is that from every viewing position in the room, the spectator is drawn into the drama of the picture’s narrative with equal force. And dramatic it is. Whereas traditionally the Last Supper was pictured at the moment of communion, a moment of calm, individual meditation for each apostle, Leonardo chose the ominous moment when Jesus says, “One of you will betray me.”