Persistence is the most powerful force on earth, it can move mountains.

There is, however, one other human right which is infrequently mentioned but which seems to be destined to become very important: this is the right, or the duty, of the individual to abstain from cooperating in activities which he considers wrong or pernicious.

From the standpoint of daily life, however, there is one thing we do know: that we are here for the sake of each other.

The opinion prevailed among advanced minds that it was time that belief should be replaced increasingly by knowledge; belief that did not itself rest on knowledge was superstition, and as such had to be opposed.

Understanding physics is child's play when compared to understanding child's play.

An oligarchy of private capital cannot be effectively checked even by a democratically organized political society because under existing conditions, private capitalists inevitably control, directly or indirectly, the main sources of information.

Marvellous, what ideas the young people have these days. But I don't believe a word of it.