An artist who lacks the power of self-criticism accomplishes but little. It is good if your work stands higher than your own opinion of it; bad if it is on the same level. But it is a great disaster if your work stands lower than your judgment of it.

Truth at last cannot be hidden. Dissimulation is of no avail. Dissimulation is to no purpose before so great a judge. Falsehood puts on a mask. Nothing is hidden under the sun.

All our knowledge is the offspring of our perceptions.

All objects transmit their image to the eye in pyramids and the nearer to the eye these pyramids are intersected the smaller will the image appear of the objects which cause them.

The vine that has grown old on an old tree falls with the ruin of that tree, and through that bad companionship must perish with it.

It had long since come to my attention that people of accomplishment rarely sat back and let things happen to them. They went out and happened to things.

True and great love springs out of great knowledge, and where you know little you can love but little or not at all.