Freedom of thought is best promoted by the gradual illumination of men’s minds which follows from the advance of science.

Blushing is the most peculiar and most human of all expressions.

From my early youth I have had the strongest desire to understand or explain whatever I observed. ... To group all facts under some general laws.

Natural selection acts solely by accumulating slight successive favorable variations, it can produce no great or sudden modification; it can act only by very short steps.

Language is an art, like brewing or baking.... It certainly is not a true instinct, for every language has to be learnt.

How fleeting are the wishes and efforts of man! how short his time! and consequently how poor will his products be, compared with those accumulated by nature during whole geological periods. Can we wonder, then, that nature's productions should be far 'truer' in character than man's productions; that they should be infinitely better adapted to the most complex conditions of life, and should plainly bear the stamp of far higher workmanship?

It is not the most intellectual of the species that survives; it is not the strongest that survives; but the species that survives is the one that is able best to adapt and adjust to the changing environment in which it finds itself.