The youth of an art is, like the youth of anything else, its most interesting period. When it has come to the knowledge of good and evil it is stronger, but we care less about it.

There are three principal means of acquiring knowledge... observation of nature, reflection, and experimentation. Observation collects facts reflection combines them experimentation verifies the result of that combination.

Intuition and concepts constitute... the elements of all our knowledge, so that neither concepts without an intuition in some way corresponding to them, nor intuition without concepts, can yield knowledge.

If a little knowledge is dangerous, where is the man who has so much as to be out of danger?

The greatest gift is the passion for reading. It is cheap, it consoles, it distracts, it excites, it gives you knowledge of the world and experience of a wide kind. It is a moral illumination.