Certainty ends inquiry.

The child is not a prisoner of its inheritance; it holds its inheritance as a new creation which its future actions will unfold.

It is important that students bring a certain ragamuffin, barefoot irreverence to their studies; they are not here to worship what is known, but to question it.

The largest single step in the ascent of man is the change from nomad to village agriculture.

Knowledge is not a loose leaf notebook of facts.

Dissent is the mark of freedom, as originality is the mark of independence of mind. … No one can be a scientist … if he does not have independence of observation and of thought.

The paradox of knowledge is not confined to the small, atomic scale; on the contrary, it is as cogent on the scale of man, and even of the stars.