Of all studies, the one he would rather have avoided was that of his own mind. He knew no tragedy so heartrending as introspection.

The study of history is useful to the historian by teaching him his ignorance of women.

The whole fabric of society will go to wrack if we really lay hands of reform on our rotten institutions. From top to bottom the whole system is a fraud, all of us know it, laborers and capitalists alike, and all of us are consenting parties to it.

A parent gives life, but as parent, gives no more. A murderer takes life, but his deed stops there. A teacher affects eternity; he can never tell where his influence stops.

After Gibbs, one the most distinguished [American scientists] was Langley, of the Smithsonian. ... He had the physicist's heinous fault of professing to know nothing between flashes of intense perception. ... Rigidly denying himself the amusement of philosophy, which consists chiefly in suggesting unintelligible answers to insoluble problems, and liked to wander past them in a courteous temper, even bowing to them distantly as though recognizing their existence, while doubting their respectibility.

Politics cannot stop to study psychology Its methods are rough; its judgments rougher still.

Power when wielded by abnormal energy is the most serious of facts.