I suppose you are two fathoms deep in mathematics, and if you are, then God help you. For so am I, only with this difference: I stick fast in the mud at the bottom, and there I shall remain.

It's an awful stretcher to believe that a peacock's tail was thus formed but ... most people just don't get it - I must be a very bad explainer

If worms have the power of acquiring some notion, however rude, of the shape of an object and over their burrows, as seems the case, they deserve to be called intelligent; for they act in nearly the same manner as would man under similar circumstances.

With highly civilised nations continued progress depends in a subordinate degree on natural selection; for such nations do not supplant and exterminate one another as do savage tribes.

... not one living species will transmit its unaltered likeness to a distant futurity.

If I had not been so great an invalid, I should not have done so much as I have accomplished.

It strikes me that all our knowledge about the structure of our Earth is very much like what an old hen would know of the hundred-acre field in a corner of which she is scratching.