Human life is driven forward by its dim apprehension of notions too general for its existing language.

The true method of discovery is like the flight of an aeroplane. It starts from the ground of particular observation; it makes a flight in the thin air of imaginative generalization; and it again lands for renewed observation rendered acute by rational interpretation.

[In many circumstances,] the most important thing about a proposition is not that it be true, but that it be interesting.

An enormous part of our mature experience cannot not be expressed in words.

The whole of mathematics consists in the organization of a series of aids to the imagination in the process of reasoning.

If a dog jumps into your lap, it is because he is fond of you; but if a cat does the same thing, it is because your lap is warmer.

The worth of men consists in their liability to persuasion. They can persuade and can be persuaded by the disclosure of alternatives, the better and the worse. Civilization is the maintenance of social order, by its own inherent persuasiveness as embodying the nobler alternative. The recourse to force, however, unavoidable, is a disclosure of the failure of civilization, either in the general society or in a remnant of individuals. Thus in a live civilization there is always an element of unrest.