A person's genetic endowment, a product of the evolution of the species, is said to explain part of the workings of his mind and his personal history the rest.

Any single historical event is too complex to be adequately known by anyone. It transcends all the intellectual capacities of men. Our practice is to wait until a sufficient number of details have been forgotten. Of course things seem simpler then! Our memories work that way; we retain the facts which are easiest to think about.

If the world is to save any part of its resources for the future, it must reduce not only consumption but the number of consumers.

Those who have had anything useful to say have said it far too often, and those who have had nothing to say have been no more reticent.

A failure is not always a mistake, it may simply be the best one can do under the circumstances. The real mistake is to stop trying.

Overcrowding can be corrected only by inducing people not to crowd, and the environment will continue to deteriorate until polluting practices are abandoned.

To say that... behaviors have different 'meanings' is only another way of saying that they are controlled by different variables.