Old men tend to forget what thought was like in their youth; they forget the quickness of the mental jump, the daring of the youthful intuition, the agility of the fresh insight. They become accustomed to the more plodding varieties of reason, and because this is more than made up by the accumulation of experience, old men think themselves wiser than the young.

There is a single light of science, and to brighten it anywhere is to brighten it everywhere.

There’s nothing to it. All you have to do is take a close look at yourself and you will understand everyone else. We’re in no way different ourselves... You show me someone who can’t understand people and I’ll show you someone who has built up a false image of himself.

I am not a speed reader. I am a speed understander.

The Three Theorems of Psychohistorical Quantitivity: The population under scrutiny is oblivious to the existence of the science of Psychohistory. The time periods dealt with are in the region of 3 generations. The population must be in the billions (±75 billions) for a statistical probability to have a psychohistorical validity.

Scientific truth is beyond loyalty and disloyalty.

Of course there are worlds. Millions of them! Every star you see has worlds, and most of those you don't see.