One main factor in the upward trend of animal life has been the power of wandering.

We think of the number "five" as applying to appropriate groups of any entities whatsoever - to five fishes, five children, five apples, five days... We are merely thinking of those relationships between those two groups which are entirely independent of the individual essences of any of the members of either group. This is a very remarkable feat of abstraction; and it must have taken ages for the human race to rise to it

Great people plant trees they'll never sit under.

There is only one subject matter for education, and that is Life in all its manifestations

Algebra reverses the relative importance of the factors in ordinary language.

"One and one make two" assumes that the changes in the shift of circumstance are unimportant. But it is impossible for us to analyze this notion of unimportant change.

Everyone is a philosopher. Not everyone is good at it.