My deep religiosity [...] found an abrupt ending at the age of twelve, through the reading of popular scientific books.

Logic will get you from A to B. Imagination will take you everywhere.

External conditions can, to a certain extent, reduce, but never cancel individual repsonsibility.

I have lived to prove Thoreau's contention that a man is rich in proportion to the number of things which he can afford to let alone.

Isn't it strange that I who have written only unpopular books should be such a popular fellow?

The harmony of natural law reveals an Intelligence of such superiority that, compared with it, all the systematic thinking and acting of human beings is an utterly insignificant reflection.

The only thing we can be certain of in this life is that we can be certain of nothing.