My experience of the world is that things left to themselves don't get right.

The great thing in the world is not so much to seek happiness as to earn peace and self-respect.

Agnosticism, in fact, is not a creed, but a method, the essence of which lies in the rigorous application of a single principle. ... Positively the principle may be expressed: In matters of the intellect, follow your reason as far as it will take you, without regard to any other consideration. And negatively: In matters of the intellect, do not pretend that conclusions are certain which are not demonstrated or demonstrable.

Science and literature are not two things, but two sides of one thing.

My reflection, when I first made myself master of the central idea of the 'Origin', was, 'How extremely stupid not to have thought of that!'

The only freedom I care about is the freedom to do right; the freedom to do wrong I am ready to part with on the cheapest terms to anyone who will take it of me

I have always been, am, and propose to remain a mere scholar. All that I have ever proposed to myself is to say, this and this I have learned; thus and thus have I learned it; go thou and learn better; but do not thrust on my shoulders the responsibility for your own laziness if you elect to take, on my authority, conclusions the value of which you ought to have tested for yourself.