A politician normally prospers under democracy in proportion ... as he excels in the invention of imaginary perils and imaginary defenses against them.

Bridges would not be safer if only people who knew the proper definition of a real number were allowed to design them.

I never listen to debates. They are dreadful things indeed. The plain truth is that I am not a fair man, and don't want to hear both sides. On all known subjects, ranging from aviation to xylophone-playing, I have fixed and invariable ideas. They have not changed since I was four or five.

Even a superstitious man has certain inalienable rights: the right to harbor and indulge his imbecilities, provided only that he does not try to inflict them upon others by force; he has the right to argue for them as eloquently as he can. But he has no right to be protected from the criticism of those who do not hold them. He has no right to demand that they be treated as sacred. He has no right to preach them without challenge.

Man is a beautiful machine that works very badly. He is like a watch of which the most that can be said is that its cosmetic effect is good.

A man is called a good fellow for doing things which, if done by a woman, would land her in a lunatic asylum.

I believe in only one thing and that thing is human liberty.