A life without adventure is likely to be unsatisfying, but a life in which adventure is allowed to take whatever form it will is sure to be short.

The most essential characteristic of scientific technique is that it proceeds from experiment, not from tradition.

Of all forms of caution, caution in love is perhaps the most fatal to true happiness.

Folly is perennial and yet the human race has survived.

The human race may well become extinct before the end of the century.

In regard to the past, where contemplation is not obscured by desire and the need for action, we see, more clearly than in the lives about us, the value for good and evil, of the aims men have pursued and the means they have adopted. It is good, from time to time, to view the present as already past, and to examine what elements it contains that will add to the world's store of permanent possessions, that will live and give life when we and all our generation have perished.

Answering questions is a major part of sex education. Two rules cover the ground. First, always give a truthful answer to a question; secondly, regard sex knowledge as exactly like any other knowledge.