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Leonardo da Vinci: Drawn portraitDrawn portraitAttributed to Francesco Melzi; colour-corrected reproduction · Public domain

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Leonardo da Vinci

Life dates: 1452 AD — 1519 AD

Artist and observer whose notebooks connect looking, drawing and inquiry into nature. These archive passages come from a 1906 English selection of his notes, not a continuous philosophical book composed by Leonardo.

Source editions and anthology attributions are not the same evidence level. Read the selection standard ↗

▷ Play this voiceSearch these words ↗Place in time ↗lifedeathknowledgelovewisdomworkwealthmind

Life and writing

Leonardo da Vinci lived from 1452 to 1519. Drawing was central to his investigation of the visible world: observations of bodies, movement and natural forms could become studies for art as well as records of inquiry. His surviving notes and drawings show a practice in which looking closely and asking how something works often belonged to the same activity.

The notebooks preserve working material rather than a single finished argument, including inquiries into different subjects. Thoughts on Art and Life arranges selected passages in a later English edition, translated by Maurice Baring and edited by Lewis Einstein. Reading each complete numbered selection with its section title helps distinguish reflections on knowledge from practical instructions or a historical scientific claim.

Reading this voice

Begin with a passage about knowledge or observation, then explore the Life, Art and Science sections of the same source edition. A memorable image is not evidence that a historical scientific claim is correct. The 1906 selection and translation postdate Leonardo’s life; its unit numbers belong to that edition. The archive’s approximate 1486 coordinate is his lifetime midpoint, not a date attached to the words.

Subjects to explore

knowledgenaturelearningmind

Words to begin with

Profile sources and editorial notes

Agent-assisted editorial profile, updated 2026-10-04. A human reviewer is not recorded. Biographical context does not independently authenticate every quotation attributed to this person.

Quotations and sayings

01c. 1486 AD
Before I proceed further I will make some experiments, because it is my intention to cite the experiment first and then to demonstrate by reasoning how such an experiment must necessarily take effect in such a manner. And this is the true rule by which investigations of natural phenomena must proceed; and although nature herself begins from the reason and ends in the result, we must pursue the contrary course and begin, as I said above, from experience and by it seek out the reason.
Leonardo da Vinci / quote
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03c. 1486 AD
It several bodies of equal weight and shape are dropped one after another at equal intervals of time, the distances between each successive body will be equally increased. The experiment to prove the above-mentioned theorem respecting motion must be made thus: Take two balls of equal weight and shape and let them fall from a great height so that when they start falling they touch one another, and let the investigator stand on the ground and watch whether the contact is maintained during their fall. This experiment must be repeated several times, so that the trial may not be marred by any accident and the experiment vitiated and the spectator deceived.
Leonardo da Vinci / quote
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04c. 1486 AD
We know definitely that sight is infinitely swift and in an instant of time perceives countless shapes, nevertheless it only sees one object at a time. Let us take an example. You, O reader, will see the whole of this written page at a glance, and you will instantly realize that it is full of various letters, but you will not realize at that moment what these letters are nor what they signify; wherefore you will have to proceed word by word and line by line to take cognizance of these letters. Again, if you wish to reach the summit of a building you must mount step by step, otherwise it will be impossible for you to reach the summit. And therefore I say to you whom nature has drawn to this art, if you wish to attain to a thorough knowledge of the forms of objects, you will begin by studying the details, and not proceed to the second until you have committed the first to memory and mastered it in practice, and if you do otherwise you will be wasting your time and protracting your studies. And remember first of all to acquire diligence, which signifies speed.
Leonardo da Vinci / quote
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05c. 1486 AD
Of the nature of the eye. Here are the forms, here the colours, here the form of every part of the universe are concentrated in a point, and that point is so great a marvel! O marvellous and stupendous necessity! thou dost compel by thy law, and by the most direct path, every effect to proceed from its cause. These things are verily miracles! I wrote in my Anatomy how in so small a space the visual faculty can be reproduced and formed again in its whole expanse.
Leonardo da Vinci / quote
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08c. 1486 AD
The pupil of the eye dilates and contracts in proportion to the variety of bright and dark objects which are reflected in it. In this case nature has afforded compensation to the visual faculty by contracting the pupil of the eye when it is offended by excess of light and by causing it to dilate when offended by excess of darkness, like the opening of the purse. And nature here behaves like the man who has too much light in his house and closes half the window, or more or less of it according to need; and when night comes he opens the window altogether so as to see better inside his house, and nature here adopts a continued process of compensation, by continually regulating and readjusting the expansion and contracting of the pupil, in proportion to the aforesaid obscurity and light which are continually reflected in it.
Leonardo da Vinci / quote
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10c. 1486 AD
This is a difficult question to answer, but I will nevertheless state my opinion. Water, which is clothed with air, desires naturally to cleave to its sphere because in this position it is without gravity. This gravity is twofold,—the gravity of the whole which tends to the centre of the elements, and the gravity which tends to the centre of the waters of the spherical orb; if this were not so the water would form a half sphere only, which is the sphere described from the centre upwards. But I see no means in the human mind of acquiring knowledge with regard to this. We must say, as we say of the magnet which attracts iron, that such a virtue is an occult property of which there is an infinite quantity in nature.
Leonardo da Vinci / quote
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12c. 1486 AD
If the water which rises on the summits of the mountains comes from the sea, whence it is propelled by its weight to a greater height than that of the mountains, why has this portion of the element of water the power to elevate itself to such an altitude and to penetrate the earth by so great an expenditure of labour and time, when the residue of the element of water, whose only obstacle is the air which does not impede it, is not able to raise itself to a similar altitude? And thou who didst devise this theory, go and study nature, so that thou mayst cease to acquire such opinions of which thou hast made so great a collection, together with the capital and interest which thou dost possess.
Leonardo da Vinci / quote
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15c. 1486 AD
Why does not the weight remain in its place? It does not remain because it has no resistance. And whither will it tend? It will tend to the centre of the earth. And why not along other lines? Because the weight which meets with no resistance will descend by the shortest way to the lowest depth, and the lowest depth is the centre of the earth. And how does a weight find the centre of the earth with such directness? Because it does not proceed at random, wandering by diverse courses.
Leonardo da Vinci / quote
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19c. 1486 AD
The act of cutting out the nostrils of a horse is a piece of ludicrous folly. And the foolish indulge in this practice as though they considered nature had failed to supply necessary wants, and man had therefore to supplement her work. Nature made two apertures in the nose, which each in itself is half as large as the lung pipe whence breath proceeds, and if these apertures did not exist the mouth would abundantly suffice for breathing purposes. And if you said to me, Why has nature thus provided animals with nostrils if respiration through the mouth is sufficient?—I would answer that nostrils are made to be used when the mouth is employed in masticating its food.
Leonardo da Vinci / quote
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21c. 1486 AD
Nature has so placed the leaves of the latest shoots of many trees that the sixth leaf is always above the first, and thus in continued succession unless the rule is obstructed. And this she has done for two useful purposes in the plant: firstly, since the branches and the fruit of the following year spring from the bud or eye which is above and in contact with the juncture of the leaves, the water which feeds the shoot may be able to run down and nourish the bud, through the drop being caught in the hollow whence the leaf springs. And the second advantage is that as these buds shoot in the following year, one will not be covered by the other, since the five shoots spring on five different sides.
Leonardo da Vinci / quote
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