Each of us is in fact what he is almost exclusively by virtue of his imitative-ness.

I don't sing because I'm happy; I'm happy because I sing.

We can change our circumstances by a mere change of our attitude.

Good-humor is a philosophic state of mind; it seems to say to Nature that we take her no more seriously than she takes us. I maintain that one should always talk of philosophy with a smile.

Men habitually use only a small part of the power which they actually possess.

Round about the accredited and orderly facts of every science there ever floats a sort of dust-cloud of exceptional observations, of occurrences minute and irregular and seldom met with, which it always proves more easy to ignore than to attend to... Anyone will renovate his science who will steadily look after the irregular phenomena, and when science is renewed, its new formulas often have more of the voice of the exceptions in them than of what were supposed to be the rules.

When thoughts do not neutralize an undesirable emotion, action will.