Many theories of the ancient world seem terribly childish today, a hodge-podge of fables and false comparisons.But our theories will seem childish five-hundred years from now.Every theory is based on some analogy, and sooner or later the theory fails because the analogy turns out to be false. A theory in its day helps to solve the problems of the day.

The child is not a prisoner of its inheritance; it holds its inheritance as a new creation which its future actions will unfold.

There is no absolute knowledge. And those who claim it, whether they are scientists or dogmatists, open the door to tragedy.

Fifty years from now if an understanding of man's origins, his evolution, his history, his progress is not in the common place of the school books we shall not exist.

We are all shot through with enough motives to make a massacre, any day of the week that we want to give them their head.

There are two parts to the human dilemma. One is the belief that the end justifies the means. That push-button philosophy, that deliberate deafness to suffering, has become the monster in the war machine. The other is the betrayal of the human spirit: the assertion of dogma that closes the mind, and turns a nation, a civilization, into a regiment of ghosts--obedient ghosts or tortured ghosts.

The largest single step in the ascent of man is the change from nomad to village agriculture.