To such an extent does nature delight and abound in variety that among her trees there is not one plant to be found which is exactly like another; and not only among the plants, but among the boughs, the leaves and the fruits, you will not find one which is exactly similar to another.
In whatever system where the weight attached to the wheel should be the cause of motion of the wheel, without any doubt the center of the gravity of the weight will stop beneath the center of its axle. No instrument devised by human ingenuity, which turns with its wheel, can remedy this effect. Oh, speculators about perpetual motion, how many vain chimeras have you created in the like quest. Go and take you place with the seekers after gold.
To me it seems that those sciences are vain and full of error which are not born of experience, mother of all certainty, first-hand experience which in its origins, or means, or end has passed through one of the five senses.
The vivacity and brightness of colors in a landscape will never bear any comparison with a landscape in nature when it is illumined by the sun, unless the painting is placed in such a position that it will receive the same light from the sun as does the landscape.
The beginnings and ends of shadow lie between the light and darkness and may be infinitely diminished and infinitely increased. Shadow is the means by which bodies display their form. The forms of bodies could not be understood in detail but for shadow.
It reflects no great honor on a painter to be able to execute only one thing well -- such as a head, an academy figure, or draperies, animals, landscapes, or the like -- in other words, confining himself to some particular object of study. This is so because there is scarcely a person so devoid of genius as to fail of success if he applies himself earnestly to one branch of study and practices it continually.
Shadow is the obstruction of light. Shadows appear to me to be of supreme importance in perspective, because, without them opaque and solid bodies will be ill defined; that which is contained within their outlines and their boundaries themselves will be ill-understood unless they are shown against a background of a different tone from themselves.
There is nothing that deceives us more than our own judgment when used to give an opinion on our own works. It is sound in judging the work of our enemies but not that of our friends, for hate and love are two of the most powerfully motivating factors found among living things.
All our knowledge hast its origins in our perceptions … In nature there is no effect without a cause … Experience never errs; it is only your judgments that err by promising themselves effects such as are not caused by your experiments … Science is the observation of things possible, whether present or past; prescience is the knowledge of things which may come to pass.
Although the poet has as wide a choice of subjects as the painter, his creations fail to afford as much satisfaction to mankind as do paintings... if the poet serves the understanding by way of the ear, the painter does so by the eye, which is the nobler sense.
One painter ought never to imitate the manner of any other; because in that case he cannot be called the child of nature, but the grandchild. It is always best to have recourse to nature, which is replete with such abundance of objects, than to the productions of other masters, who learnt everything from her.
The instant the atmosphere is illuminated it will be filled with an infinite number of images which are produced by the various bodies and colours assembled in it. And the eye is the target, a lodestone, of these images.
O neglectful Nature, wherefore art thou thus partial, becoming to some of thy children a tender and benignant mother, to others a most cruel and ruthless stepmother? I see thy children given into slavery to others without ever receiving any benefit, and in lieu of any reward for the services they have done for them they are repaid by the severest punishments.
When the sun is covered by clouds, objects are less conspicuous, because there is little difference between the light and shade of the trees and the buildings being illuminated by the brightness of the atmosphere which surrounds the objects in such a way that the shadows are few, and these few fade away so that their outline is lost in haze.
Experience, the interpreter between creative nature and the human race, teaches the action of nature among mortals: how under the constraint of necessity she cannot act otherwise than as reason, who steers her helm, teaches her to act.
Demetrius was wont to say that there was no difference between the words and speech of the unskilled and ignorant and the sounds and rumblings caused by the stomach being full of superfluous wind. This he said, not without reason, for, as he held, it did not in the least matter from what part of them the voice emanated, whether from the lower parts or the mouth, since the one and the other were of equal worth and importance.
Now do you not see that the eye embraces the beauty of the whole world? It counsels and corrects all the arts of mankind... it is the prince of mathematics, and the sciences founded on it are absolutely certain. It has measured the distances and sizes of the stars it has discovered the elements and their location... it has given birth to architecture and to perspective and to the divine art of painting.
Music may be called the sister of painting, for she is dependent upon hearing, the sense which comes second and her harmony is composed of the union of proportional parts sounded simultaneously, rising and falling in one or more harmonic rhythms.
The fox when it sees a flock of herons or magpies or birds of that kind, suddenly flings himself on the ground with his mouth open to look as he were dead; and these birds want to peck at his tongue, and he bites off their heads.
O sleepers! what a thing is slumber! Sleep resembles death. Ah, why then dost thou not work in such wise as that after death thou mayst retain a resemblance to perfect life, when, during life, thou art in sleep so like to the hapless dead?