Hardly any original thoughts on mental or social subjects ever make their way among mankind or assume their proper importance in the minds even of their inventors, until aptly selected words or phrases have as it were nailed them down and held them fast.

My father never permitted anything which I learnt to degenerate into a mere exercise of memory. He strove to make the understanding not only go along with every step of the teaching but...precede it.

In its narrowest acceptation, order means obedience. A government is said to preserve order if it succeeds in getting itself obeyed.

No one can be a great thinker who does not recognize that as a thinker it is his first duty to follow his intellect to whatever conclusions it may lead.

Since the general or prevailing opinion on any subject is rarely or never the whole truth, it is only by the collision of adverse opinion that the remainder of the truth has any chance of being supplied.

Each undervalues that part of the materials of thought with which he is not familiar.

Ask yourself whether you are happy and you cease to be so. The only chance is to treat not happiness, but some end external to it, as the purpose of life.