average human “looks without seeing, listens without hearing, touches without feeling, eats without tasting, moves without physical awareness, inhales without awareness of odour or fragrance, and talks without thinking.

For those colours which you wish to be beautiful, always first prepare a pure white ground.

The eye transmits its own image through the air to all the objects which face it, and also receives them on its own surface, whence the "sensus communis" takes them and considers them.

The painter strives and competes with nature.

O time, swift robber of all created things, how many kings, how many nations hast thou undone, and how many changes of states and of various events have happened since the wondrous forms of this fish perished here in this cavernous and winding recess. Now destroyed by time thou liest patiently in this confined space with bones stripped and bare; serving as a support and prop for the superimposed mountain.

It is easier to contend with evil at the first than at the last.

We must doubt the certainty of everything which passes through the senses, but how much more ought we to doubt things contrary to the senses, such as the existence of God and the soul.