Leonardo da Vinci by Walter Isaacson

Publisher: Simon & Schuster

ISBN-13 : 978-1501139154

Rating: ⭐⭐⭐⭐⭐

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Introduction

Leonardo da Vinci was famous for his art, but he also thought of himself equally as a scientist and engineer. In his letter seeking employment from the Duke of Milan, Leonardo dedicated the first ten paragraphs to highlighting his engineering expertise, only mentioning his artistic abilities as an afterthought. “Likewise in painting, I can do everything possible,” he wrote.” (9, loc. 133-136)

Leonardo saw art and science as intertwined disciplines. Leonardo’s art was deeply informed by his scientific explorations. He was always looking for connections between different disciplines. He believed that to make art that was interesting and realistic, you needed to really understand the world, including the human form and the laws of nature.

Anatomy and Dissection: 

• Leonardo’s interest in anatomy stemmed from his desire to understand the human body and its relationship to art.
  • Leonardo’s anatomy studies were another example of the influence of the printing press, which was spawning publishing houses throughout Italy. pg. 391, loc. 5985-5986
  • By then Leonardo owned 116 books, including Johannes de Ketham’s Fasciculus Medicinae, published in Venice in 1498; Bartolomeo Montagnana’s Tractatus de Urinarum, published in Padua in 1487; and Anatomice, by Leonardo’s contemporary Alessandro Benedetti, printed in Venice in 1502. pg. 391, loc. 5986-5988
  • He had an edition of the standard dissection guide by the Bologna physician Mondino de Luzzi, which had been written in about 1316 and was printed in Italian in 1493. pg. 391, loc. 5988-5989
  • He used Mondino’s book as a manual for his early dissections, and he even replicated one of Mondino’s mistakes in identifying some of the muscles of the abdomen. pg. 391, loc. 5989-5990
• Leonardo conducted extensive anatomical studies, dissecting cadavers to understand the structure and function of muscles, bones, and internal organs, and to improve the accuracy and realism of his paintings. 
  • But, true to form, Leonardo preferred learning from experiment rather than from established authority. pg. 391, loc. 5991-5992
• This knowledge is evident in his paintings, which accurately depict human anatomy and movement. For instance, his understanding of the muscles that move the lips helped him to depict the Mona Lisa’s mysterious and memorable smile.
  • Leonardo was especially interested in how the human brain and nervous system translate emotions into movements of the body. pg. 397, loc. 6085-6085
  • first known examples of the scientific anatomy of the human smile. pg. 400, loc. 6123-6124
  • At the time when he was perfecting Lisa’s smile, Leonardo was spending his nights in the depths of the morgue under the hospital of Santa Maria Nuova, peeling the flesh off cadavers and exposing the muscles and nerves underneath. (469, loc. 7187-7189) 

• His anatomical drawings are remarkable for their detail and precision.He studied muscles, bones, and organs, and his notebooks contain numerous sketches and observations on human anatomy.
  • On the left-hand page he drew, with delicate strokes of a pen, two views of a human skull with veins. On the right-hand page, he listed topics to explore: ( 215, loc. 3290-3291) 
  • What nerve is the cause of the eye’s movement and makes the movement of one eye move the other? Of closing the eyelid. Of raising the eyebrows. . . . Of parting the lips with teeth clenched. Of bringing the lips to a point. Of laughing. Of expressing wonder. Set yourself to describe the beginning of man when he is created in the womb and why an infant of eight months does not live. What sneezing is. What yawning is. Epilepsy. Spasm. Paralysis. . . . Fatigue. Hunger. Sleep. Thirst. Sensuality. . . . Of the nerve that causes the movement of the thigh. And from the knee to the foot and from the ankle to the toes. (215, loc. 3291-3304) 
  • Thus did Leonardo pioneer a new form of anatomical drawing, perhaps better described in his case as anatomical art, that is still in use today.(217, loc. 3324-3325)
• Leonardo’s anatomical studies, while groundbreaking, had limited impact on the development of modern anatomy because he did not publish his findings.
  • His most important hands-on inquiries came during the winter of 1510–11, when he collaborated with Marcantonio della Torre, a twenty-nine-year-old anatomy professor at the University of Pavia. pg. 391, loc. 5992-5993
  • The young professor provided the human cadavers—probably twenty of them were dissected that winter—and lectured while his students did the actual cutting and Leonardo made notes and drawings. pg. 391, loc. 5994-5995
  • During this period of intense anatomical study, Leonardo made 240 drawings and wrote at least thirteen thousand words of text, illustrating and describing every bone, muscle group, and major organ in the human body for what would have been, if it had been published, his most historic scientific triumph. pg. 392, loc. 5996-5998
  • Marcantonio died in 1511 of the plague that was devastating Italy that year. It is enticing to imagine what he and Leonardo could have accomplished. pg. 392, loc. 6001-6002
  • One of the things that could have most benefited Leonardo in his career was a partner who would help him follow through and publish his brilliant work. Together he and Marcantonio could have produced a groundbreaking illustrated treatise on anatomy that would have transformed a field still dominated by scholars who mainly regurgitated the notions of the second-century Greek physician Galen. pg. 392, loc. 6002-6004

Optics and Perspective: 

• Leonardo’s study of optics, the science of light, was critical to his artistic technique. He explored how light rays strike the cornea and how shadows and highlights create the illusion of three-dimensionality on a two-dimensional surface. 
• This mastery of light and shadow, known as chiaroscuro, is evident in paintings like The Last Supper, where he used perspective and shading to create a sense of depth and realism.
• By connecting his studies of light and optics to his art, he mastered the use of shading and perspective to model objects on a two-dimensional surface to make them look three-dimensional.
• Dimensionality, in large part due to Leonardo’s work, became the primary innovation of Renaissance art.

Mechanics and Motion:

• Leonardo’s interest in motion connected his fascination with machines and the human body.
• He saw both as machines designed to move and created exploded and layered drawings to illustrate how motion is transferred.
• He was more interested in a part-by-part analysis of motion transfer than depicting machines as a whole.
• Leonardo’s notebooks are filled with beautiful and meticulous drawings that explore how to maintain constant motion in a device powered by a coiled spring.
  • Leonardo’s interest in machinery was linked to his fascination with motion. He saw both machines and humans as apparatuses designed to move, with analogous components such as cords and sinews. (195, loc. 2975-2977)  
  • he drew machines disassembled—using exploded and layered views—to show how motion is transferred from gears and levers to wheels and pulleys, (195, loc. 2977-2978)  
  • Leonardo, on the other hand, was interested in a part-by-part analysis of the transfer of motion. (195, loc. 2980-2981)  
  • Rendering each of the moving parts—ratchets, springs, gears, levers, axles, and so on—was a method to help him understand their functions and engineering principles. (195, loc. 2981-2982)
  • For example, Leonardo showed how the energy of humans could be used to pump a treadmill or turn a crank; that power could then be transmitted by gears and pulleys to perform a function. To capture human energy most efficiently, he broke the human body into components; he illustrated how each muscle works, calculated its power, and showed methods for leveraging it. (196, loc. 3000-3002)
  • Only one of Leonardo’s military conceptions is known to have made it off the pages of his notebooks and onto the battlefield, and he arguably deserves priority as its inventor. (109, loc. 1671-1672)  
  • The wheellock, or wheel lock, which he devised in the 1490s, was a way to create a spark for igniting the gunpowder in a musket or similar hand-carried weapon. (109, loc. 1672-1673)  
  • When the trigger was pulled, a metal wheel was set spinning by a spring. As it scraped against a stone, it sparked enough heat to ignite the gunpowder. Leonardo (110, loc. 1673-1674) 
  • The wheellock came into use in Italy and Germany around that time and proved to be influential in facilitating both warfare and the personal use of guns. (110, loc. 1676-1677)  

Water Studies:

• Leonardo da Vinci was fascinated by water, studying it on multiple levels, from detailed observations to cosmic analogies. 
  • More than any other subject except the human body, hydrodynamics engaged his artistic and scientific and engineering interests, and he addressed it on various levels: detailed observations, practical inventions, grand projects, beautiful paintings, and cosmic analogies.One of his earliest drawings was of the landscape carved by the cascading Arno River. (413, loc. 6331-6334) 
  • Water provided the perfect manifestation of Leonardo’s fascination with how shapes are transformed when in motion. (414, loc. 6344-6345)
  • “running water has within itself an infinite number of movements.” (417, loc. 6386-6387)
• He was fascinated by the spiral forms he saw in water eddies, hair curls, and the vortexes created by bird wings. Recognizing the concept of impetus, which describes how a body in motion continues moving in the same direction, he drew a comparison between the forces shaping water eddies and hair curls. 
  • he made an analogy, comparing the forces that create water eddies to those that create a hair curl: (419, loc. 6413-6414)
  • the essence of what motivated Leonardo: a joy in seeing the patterns that connect two things that delighted him, (419, loc. 6417-6417)
  • He realized that vortexes likewise occur in air when it blows past an object or when a beating wing causes an area of low air pressure. Like curls of hair, these swirls of water or air form geometric patterns—a spiral—that follow mathematical laws. (420, loc. 6435-6436)
  • It is another example of willfully noticing something in nature, discovering its pattern, and applying it to other aspects of nature. (420, loc. 6436-6437)
• Drawing on his observations of spiral forms in nature, such as water eddies and hair curls, Leonardo hypothesized that the spiral flow of blood through the sinus of Valsalva in the aorta creates eddies that help close the aortic valve. This discovery, confirmed in modern times, highlights Leonardo’s ability to apply knowledge from different areas, such as hydraulics, to his anatomical studies
  • And by using his knowledge of how water pouring from a pipe causes water eddies, he was able to envision the vortexes inside the human heart and how they would close a valve. (414, loc. 6342-6343) 
• Leonardo’s water studies demonstrate his ability to see patterns and connections across disciplines, informing his understanding of anatomy, engineering, and art.

Mathematics and Geometry: 

• Leonardo was fascinated by geometry and its relationship to art and nature. He explored mathematical concepts like the golden ratio and applied them to his compositions, believing that harmony and proportion were essential for beauty. 
• His famous drawing Vitruvian Man demonstrates his understanding of human proportions and their relationship to the geometry of the circle and square. This drawing also exemplifies how his scientific pursuits directly influenced his art.
  • Leonardo increasingly came to realize that mathematics was the key to turning observations into theories. It was the language that nature used to write her laws. (202, loc. 3098-3099)  
  • “There is no certainty in sciences where mathematics cannot be applied,” he declared. He was correct. (203, loc. 3099-3100)  
  • Using geometry to understand the laws of perspective taught him how math could extract from nature the secrets of its beauty and reveal the beauty of its secrets. (203, loc. 3100-3101)  
  • He came up with 169 formulas for squaring a circular shape, and on one sheet drew so many examples that it looks like a page from a pattern book. (213, loc. 3255-3256)
  • They may not have led to historic breakthroughs in mathematics, but they were integral to his ability to perceive and portray motion—of bird wings and water, of a squirming baby Jesus and a breast-beating Saint Jerome—like no other artist before him. (213, loc. 3260-3262)

Observation and Experimentation: 

• Leonardo was a keen observer of nature and a proponent of experimentation. He was able to see patterns in nature and theorized by making analogies.
• His notebooks are filled with observations, experiments, and theories on a wide range of subjects, from the flight of birds to the flow of water. His curiosity and desire to understand the world around him led him to pursue knowledge for knowledge’s sake, in addition to improving his art.
  • Leonardo’s scientific inquiries were not merely a means to an end for his art. “As he aged, he pursued his scientific inquiries not just to serve his art but out of a joyful instinct to fathom the profound beauties of creation.” (10, loc. 150-151) 
• He believed in testing theories through observation and experience, a precursor to the modern scientific method, and that the progress of science came from a dialogue between experience and received wisdom.
• He came to understand that knowledge also came from a related dialogue: that between experiment and theory.
• This empirical approach is reflected in his art, which often features detailed and accurate depictions of the natural world, from the swirling waters of a river to the delicate curls of a baby Jesus.

Read the whole series

Part 1: Book Summary 
Part 2: The Outsider Who Revolutionized Art and Science
Part 3: Key Elements of Leonardo’s Genius and Actionable Insights
Part 4: The Interplay of Art and Science in Leonardo’s Work
Part 5: Technology and Culture as Catalysts for Genius and “Scenius”
Part 6: Leonardo da Vinci’s Note-Taking
Part 7: Leonardo, Macchiavelli, and The Prince