A mathematical equation stands forever.

The human mind has first to construct forms, independently, before we can find them in things.

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

Gravitation is not responsible for people falling in love.

Common sense is the collection of prejudices acquired by age eighteen.

Everything is determined, the beginning as well as the end, by forces over which we have no control. It is determined for the insect, as well as for the star. Human beings, vegetables, or cosmic dust, we all dance to a mysterious tune, intoned in the distance by an invisible piper.

Science is the process of making obviously erroneous ideas less obviously erroneous.