Speak out in acts; the time for words has passed, and only deeds will suffice.

The point of mathematics is that in it we have always got rid of the particular instance, and even of any particular sorts of entities. So that for example, no mathematical truths apply merely to fish, or merely to stones, or merely to colours. So long as you are dealing with pure mathematics, you are in the realm of complete and absolute abstraction. . . . Mathematics is thought moving in the sphere of complete abstraction from any particular instance of what it is talking about.

Our rate of progress is such that an individual human being, of ordinary length of life, will be called on to face novel situations which find no parallel in his past. The fixed person, for the fixed duties, who, in older societies was such a godsend, in the future will be a public danger.

Seek simplicity, and distrust it.

Great people plant trees they'll never sit under.

The consequences of a plethora of half-digested theoretical knowledge are deplorable.

You cannot evade quantity. You may fly to poetry and music, and quantity and number will face you in your rhythms and your octaves.