Error is none the better for being common, nor truth the worse for having lain neglected.

To ask at what time a man has first any ideas is to ask when he begins to perceive; having ideas and perception being the same thing.

The dread of evil is a much more forcible principle of human actions than the prospect of good.

Mathematical proofs, like diamonds, are hard and clear, and will be touched with nothing but strict reasoning.

Every man must some time or other be trusted to himself.

Reading furnishes the mind only with materials of knowledge; it is thinking that makes what we read ours.

Struggle is nature's way of strengthening it