Astronomy is perhaps the science whose discoveries owe least to chance, in which human understanding appears in its whole magnitude, and through which man can best learn how small he is.

Many things about our bodies would not seem to us so filthy and obscene if we did not have the idea of nobility in our heads.

First there is a time when we believe everything, then for a little while we believe with discrimination, then we believe nothing whatever, and then we believe everything again - and, moreover, give reasons why we believe.

To many people virtue consists chiefly in repenting faults, not in avoiding them.

The great trick of regarding small departures from the truth as the truth itself - on which is founded the entire integral calculus - is also the basis of our witty speculations, where the whole thing would often collapse if we considered the departures with philosophical rigour.

To do just the opposite is also a form of imitation.

To err is human also in so far as animals seldom or never err, or at least only the cleverest of them do so.