A life well used procures a happy death.

It is no small benefit on finding oneself in bed in the dark to go over again in the imagination the main lines of the forms previously studied, or other noteworthy things conceived by ingenious speculation.

Details make perfection, and perfection is not a detail.

It vexes me greatly that having to earn my living has forced me to interrupt the work and to attend to small matters.

But to me all sciences seem vain and full of error that are not born of experience, mother of all certainty, and do not terminate in an actual experience.

When the thing taken into union is perfectly adapted to that which receives it, the result is delight and pleasure and satisfaction.

The eye is the window of the human body through which it feels its way and enjoys the beauty of the world.