If you find from your own experience that something is a fact and it contradicts what some authority has written down, then you must abandon the authority and base your reasoning on your own findings.

The Book of the science of Mechanics must precede the Book of useful inventions.

It is a far worthier thing to read by the light of experience than to adorn oneself with the labors of others.

The smallest feline is a masterpiece.

The first object of the painter is to make a flat plane appear as a body in relief and projecting from that plane

I say that in narrative paintings one should mingle direct contraries close by, because they produce strong contrasts with one another, and all the more so when they are very close together; that is, the ugly next to the beautiful, the big to the small, the old to the young, the strong to the weak; in this way you will vary as much as possible and close by.

If you throw a stone in a pond... the waves which strike against the shores are thrown back towards the spot where the stone struck; and on meeting other waves they never intercept each other's course... In a small pond one and the same stroke gives birth to many motions of advance and recoil.