To make astute people believe one is what one is not is, in most cases, harder than actually to become what one wishes to appear.

I forget most of what I read, just as I do most of what I have eaten, but I know that both contribute no less to the conservation of my mind and my body on that account.

Theologians always try to turn the Bible into a book without common sense.

The natural scientists of the previous age knew less than we do and believed they were very close to the goal: we have taken very great steps in its direction and now discover we are still very far away from it. With the most rational philosophers an increase in their knowledge is always attended by an increased conviction of their ignorance.

Man is a masterpiece of creation if for no other reason than that, all the weight of evidence for determinism notwithstanding, he believes he has free will.

Of all the inventions of man I doubt whether any was more easily accomplished than that of a Heaven.

Diogenes, filthily attired, paced across the splendid carpets in Plato's dwelling. Thus, said he, do I trample on the pride of Plato. Yes, Plato replied, but only with another kind of pride.