Robert Anson Heinlein

"A competent and self-confident person is incapable of jealousy in anything. Jealousy is invariably a symptom of neurotic insecurity. "

"A generation which ignores history has no past and no future. "

"Everything is theoretically impossible, until it is done. One could write a history of science in reverse by assembling the solemn pronouncements of highest authority about what could not be done and could never happen. "

"Love is a condition in which the happiness of another person is essential to your own. "

"One man's religion is another man's belly laugh. "

"Self awareness is NOT just a bunch of amino acids bumping together. "

"The reasonable man adapts himself to the world the unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man. "

"The stars incline, but do not impel. "

"To be matter of fact about the world is to blunder into fantasy -- and dull fantasy at that, as the real world is strange and wonderful. "

"Your enemy is never a villain in his own eyes. Keep this in mind, it may offer a way to make him your friend. If not, you can kill him without hate--and quickly. "