Leonardo da Vinci left no polished book of sayings — what survives is roughly 7,000 pages of private notebooks, written right-to-left in mirror script. The lines below come from those notebooks, in Jean Paul Richter's 1883 English translation on Wikisource. Where the wording is an exact match to that translation, it is marked as such; everything else here is a paraphrase, or a line you should stop repeating.
On experience over authority
Leonardo distrusted men who quoted other men instead of testing things themselves:
"Though I may not, like them, be able to quote other authors, I shall rely on that which is much greater and more worthy:--on experience, the mistress of their Masters."
"My works are the issue of pure and simple experience, who is the one true mistress."
He later sharpens the same point: anyone who argues from authority alone "uses, not his understanding, but rather his memory."
On science and practice, paired
Two aphorisms from the notebooks work as a matched set:
"Mechanics are the Paradise of mathematical science, because here we come to the fruits of mathematics."
"Science is the captain, and practice the soldiers."
He warns against the opposite failure too — practice with no science behind it — comparing it to a sailor who boards "a ship without a helm or a compass, and who never can be certain whither he is going."
On staying in use
"Just as iron rusts unless it is used, and water putrifies or, in cold, turns to ice, so our intellect spoils unless it is kept in use."
A looser, more quotable version — "Iron rusts from disuse; stagnant water loses its purity" — circulates widely online under the same attribution. That phrasing does not appear verbatim in Richter's translation; the line above is the one that does.
On the body, in his own hand
The most physical line in the notebooks, from the anatomy chapter:
"I have dissected more than ten human bodies, destroying all the other members, and removing the very minutest particles of the flesh by which these veins are surrounded, without causing them to bleed."
Anatomy was not a detour from his art — it was the same investigation, continued under the skin.
Leonardo is also widely credited with comparing painting to silent poetry, and poetry to painting that is heard rather than seen — an idea that echoes his Treatise on Painting material, though the exact original wording has not been located in a primary edition checked for this page; treat it as a paraphrase, not a verbatim quotation.
From a conversation with our Leonardo
An excerpt from our AI Leonardo persona — a stylized recreation, clearly labeled; not a historical quotation.
Caller: You never finished half of what you started. Doesn't that bother you?
Leonardo: Bother me — no. A finished painting stops asking questions; an unfinished one is still working. Experience does not care if I am tidy about it. It only cares that I looked closely enough to be worth arguing with.
Quotes Leonardo never wrote
These circulate constantly as "Da Vinci quotes." None has a documented source in his notebooks:
- "Simplicity is the ultimate sophistication." No Leonardo attribution before 2003; traces to twentieth-century sources.
- "Knowing is not enough; we must apply. Being willing is not enough; we must do." This is Goethe, from Wilhelm Meister's Journeyman Years.
- "Once you have tasted flight, you will forever walk the earth with your eyes turned skyward." Absent from his writings; traced to a 1975 science-fiction story.
If a "Leonardo quote" sounds like a productivity poster, be suspicious — the real notebooks read like a working scientist's margin notes.
Hear him argue it out loud
Our Leonardo — an AI recreation, honestly labeled — argues the way the record suggests he actually thought: circling a question, testing it against something he touched or dissected, never handing you a tidy maxim.
More in this cluster: Leonardo hub · his death · biography · facts.