Whether you know the shape of a pebble or the structure of a solar system, the anxioms remain the same: that it exists and that you know it.

You'd let the whole world perish rather than soil that immaculate self of yours with a single spot of which you'd have to be ashamed.

It is too early to feel fear of the future when one is under 30, and too late after that. What I mean is that one must never allow fear to become one's permanent sense of life. The important thing is to prepare yourself intellectually to deal with whatever circumstances you may encounter, which requires that you define your values fully, clearly and rationally -- and never betray them.

The men who attempt to survive, not by means of reason, but by means of force, are attempting to survive by the method of animals.

Since reason is man’s basic means of survival, that which is proper to the life of a rational being is the good; that which negates, opposes or destroys it is the evil.

[Altruism] is a moral system which holds that man has no right to exist for his own sake, that service to others is the sole justification of his existence, and that self-sacrifice is his highest moral duty, value and virtue. This is the moral base of collectivism, of all dictatorships.

Force and mind are opposites; morality ends where a gun begins.