In every age of well-marked transition, there is the pattern of habitual dumb practice and emotion which is passing and there is oncoming a new complex of habit.

The aim of science is to seek the simplest explanation of complex facts... Seek simplicity and distrust it.

Our minds are finite, and yet even in these circumstances of finitude we are surrounded by possibilities that are infinite, and the purpose of life is to grasp as much as we can out of that infinitude.

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.

The art of progress is to preserve order amid change and to preserve change amid order.

Vigorous societies harbour a certain extravagance of objectives.

A clash of doctrine is not a disaster, it is an opportunity.