There is no more common error than to assume that, because prolonged and accurate mathematical calculations have been made, the application of the result to some fact of nature is absolutely certain.

Inventive genius requires pleasurable mental activity as a condition for its vigorous exercise. "Necessity is the mother of invention" is a silly proverb. "Necessity is the mother of futile dodges" is much closer to the truth. The basis of growth of modern invention is science, and science is almost wholly the outgrowth of pleasurable intellectual curiosity.

Identification of rhythm as the casual counterpart of life; wherever there is some life, only perceptible to us when the analogies are sufficiently close.

The absolute pacifist is a bad citizen; times come when force must be used to uphold right, justice and ideals.

The guiding motto in the life of every natural philosopher should be, seek simplicity and distrust it.

The aim of science is to seek the simplest explanation of complex facts. We are apt to fall into the error of thinking that the facts are simple because simplicity is the goal of our quest. The guiding motto in the life of every natural philosopher should be ``Seek simplicity and distrust it.''

The many become one and are increased by one.