It is my deliberate opinion that the one essential requisite of human welfare in all ways is scientific knowledge of human nature.

Laws and customs may be creative of vice; and should be therefore perpetually under process of observation and correction: but laws and customs cannot be creative of virtue: they may encourage and help to preserve it; but they cannot originate it.

The last degree of honesty has always been, and is still considered incompatible with statesmanship. To hunger and thirst after righteousness has been naturally, as it were, supposed a disqualification for affairs.

Of tobacco and its consequences, I will say nothing but that the practice is at too bad a pass to leave hope that anything that could be said in books would work a cure. If the floors of boarding-houses, and the decks of steam-boats, and the carpets of the Capitol, do not sicken the Americans into a reform; if the warnings of physicians are of no avail, what remains to be said? I dismiss the nauseous subject.

It is characteristic of genius to be hopeful and aspiring. It is characteristic of genius to break up the artificial arrangements of conventionalism, and to view mankind in true perspective, in their gradations of inherent rather than of adventitious worth. Genius is therefore essentially democratic, and has always been so.

Public opinion, - a tyrant, sitting in the dark, wrapt up in mystification and vague terrors of obscurity; deriving power no one knows from whom ... - but irresistible in its power to quell thought, to repress action, to silence conviction.

My own feeling of concern arises from seeing how much moral injury and suffering is created by the superstitions of the Christian mythology.