Everyone thinks of Leonardo da Vinci as the paragon of Renaissance virtue. He could paint, design, and use intuition as an aid to creativity, when he felt like doing so. But a closer look at the record paints a picture of a chronic procrastinator, a man of dubious reliability, and an idler who was more preoccupied with his daydreams than with perfecting his craft. He had genius, of course. But that is never enough. Harness, discipline, and application are far more important.
Laudatory writings about him list his “interests” as evidence of his greatness, but conspicuously fail to mention that he contributed almost nothing of worth to all of these ancillary fields that he was “interested” in. No one doubts his incredible genius; but we cannot overlook his very meager output. Genius locked away in unpublished notebooks is genius wasted. He is primarily known for his painting. But in practice, he seemed more interested in solving the technical problems of composition than in the actual execution of a work. It seems he used assistants to fill in large parts of his paintings based on instructions he provided. Even worse than this was the pitifully small number of works that he produced in his lifetime. For a painter of his caliber, the final count is not at all impressive.
The Mona Lisa, his most famous painting, took him about 15 years to finish; and his Virgin on the Rocks took even longer, perhaps 20 years. These facts are indicators of a mind unable to focus, or to discipline itself, to the task at hand. One of his most famous paintings is The Last Supper, which Leonardo was hired to paint for the refectory of the Convent of Santa Maria della Grazie in Milan. In its technical details, the work is incredible, of course.
There are precise geometric proportions that underlie the work, and the viewer’s attention is kept focused (as it should be) on the faces of the disciples present. But Leonardo had to be hounded night and day by his patrons. He worked in short bursts of activity, followed by periods of inactivity. It was the same story with nearly all of his works. He would be commissioned to get some project done, and would then settle into a predictable pattern of behavior. An initial burst of energy would quickly fizzle out, and Leonardo would then putter along in fits and starts until his employers lost patience with him. An observer (Matteo Bandello) who actually watched Leonardo working on The Last Supper recorded that the artist would on occasion work all day without taking a break (even for meals), and then promptly lapse into inactivity that might drag on for several days. Leonardo had to be badgered relentlessly in order for anything to get done. Worse still, for all the glowing praise that has been showered on him for his supposed technical wizardry, he executed the painting incompetently.
For a painter of his commission, this was simply inexcusable. Leonardo had chosen not to use the tried-and-true method of fresco painting, almost certainly because it would have required him to work efficiently. In fresco painting, the paint is applied directly to wet plaster, so that when both dry, they form an inseparable union with each other. A fresco painter cannot waste time; he must move quickly to get the project done. Instead, Leonardo opted for a method that was completely unsuited to the task. He used tempera paints on a base of gesso; this ensured that the paint did not adhere deeply to the wall surface. Within less than a hundred years after Leonardo completed work, it was described by one viewer as “completely ruined.”
One can only imagine how this must have frustrated and enraged his patrons, who were paying him well to see meaningful results. But Leonardo was impervious to the criticisms of others; living in his own world, and without a family to support, he could afford to spend his days wandering around the Italian countryside, pondering nearly everything that arrested his fancy. There is nothing wrong with this, of course; it has been the catalyst for productive genius since the beginning of time. But at some point, speculation must give way to application. Thought must be set aside in favor of execution. And this was where Leonardo faltered, over and over again.
To provide another example of Leonardo’s inability to get things done, we can point to the immense statue of a horse that he planned to construct. It was intended as an equestrian monument to Francisco Sforza, and has also been called the “Gran Cavallo” (i.e., Big Horse). As usual, he pored over every detail lovingly, as he was especially fond of animals.
More than seventy tons of bronze were actually allocated for its casting. Leonardo completed a huge clay model of the horse in 1492, but this model was destroyed by invading French military forces in 1499. They used it for target practice. Thus the Gran Cavallo remained like so many of Leonardo’s abortive projects: unfinished and eventually forgotten. Leonardo’s fame as a Renaissance polymath rests almost entirely on his voluminous notebooks, which were discovered long after his death. In these impressive collections, he records drawings and designs for all sorts of subjects: engines of war, agricultural inventions, natural history, geology, the activity of animals, mathematics, and similar subjects.
We acknowledge his great abilities, of course. But is “interest” in a subject area enough for one to claim recognition in that field? Where are the tangible fruits of his labors? Where are the actual inventions? And did these notebooks even exert any influence in history? The answer must be a resounding negative. Beyond their curiosity value, the notebooks do not contain any hidden engineering “secrets,” nor were they the catalyst for any future discoveries.
Popular mythology here has entirely obscured the reality of the situation. Leonardo never saw fit to edit or publish his drawings or speculations. The reason why was that he was simply too lazy to endure the arduous drudgery of putting a book together. It was easier to speculate. Even the drawings are much overrated in their inventive power. If we wish to find a polymath who actually has achievements to his credit, Benjamin Franklin cuts far more impressive a figure than does Leonardo. Leonardo had no practical experience with mechanics, metallurgy, or engineering, and this is evident in his drawings. Almost all of them are impractical, or would not work as he intended them to do. Even his notebooks do not seem to have inspired many later engineers or inventors. They have value in shedding light on Leonardo’s personality, but beyond this, there is little that the world has gained from them. His fame rests largely on the romanticized image of him that later centuries would confer on him; but this halo obscured more than it revealed.
Some biographers have made exaggerated claims about these notebooks, finding in them evidence of “scientific researches” that “foreshadow” or “anticipate” or “inspire” the work of actual scientists centuries later. The very fact that historians have to resort to such vague qualifiers is testimony to Leonardo’s inadequacy as a true scientist. It is true that Leonardo made significant and original investigations in anatomy (especially in the workings of the valves of the heart) and fluid dynamics; but these observations were never distilled into identifiable hypotheses that could be evaluated by others. Kepler, Tycho Brahe, Copernicus, and Galileo are rightly called scientists because they arduously collected data and then performed the labor of synthesizing that data into hypotheses.
Leonardo failed in three of the most important duties of a scientist: the systematic recordation of data, regular collaboration with like-minded peers, and the dissemination of verifiable results. He was an artist with scientific inclinations, but he was not a scientist. What is so frustrating about Leonardo’s scientific researches is that he lost interest in them at precisely the moment when intense concentration and labor were needed to reap the fruits of his experiments. Leonardo published not one book, either during his life or posthumously.
When he died in 1519 at the age of 67, he had only completed 15 paintings. This is a pitifully small number for an artist of his caliber. Contrast this to the inexhaustible energy of Michelangelo, who worked himself to death and slept with his boots on, eager for the start of a new day of work. Genius is not enough: it must be sharpened to a fine point by diligent application, discipline, and relentless work. And this Leonardo was maddeningly unable to do. There is an Arabic proverb that emphasizes the critical difference between thinking about something, and implementing something:
 من تفكر اعتبر و من اعتبر اعتزل و من اعتزل سلم
And this means, “He who thinks about things, takes examples from them, and he who takes such lessons, separates himself from other men; and he who separates himself from others, is saved.” Stated another way, cogitation is not enough: we must put our lessons into practice, and produce something.
 From Freytag’s Arabum Proverbia (III, no. 2395): Qui de rebus cogitat, exemplum ab iis sumit, et qui exemplum sumit, ab hominibus se separat, et qui se separat, salvus est.
Read Stoic Paradoxes today.