A man who dares to waste one hour of time has not discovered the value of life.

We can allow satellites, planets, suns, universe, nay whole systems of universe[s], to be governed by laws, but the smallest insect, we wish to be created at once by special act.

As for a future life, every man must judge for himself between conflicting vague probabilities.

It is those who know little, and not those who know much, who so positively assert that this or that problem will never be solved by science.

Man still bears in his bodily frame the indelible stamp of his lowly origin.

In the struggle for survival, the fittest win out at the expense of their rivals because they succeed in adapting themselves best to their environment.

Doing what little one can to increase the general stock of knowledge is as respectable an object of life, as one can in any likelihood pursue.

Ignorance more frequently begets confidence than does knowledge.

I love fools' experiments. I am always making them.

Nothing before had ever made me thoroughly realise, though I had read various scientific books, that science consists in grouping facts so that general laws or conclusions may be drawn from them.

A scientific man ought to have no wishes, no affections, -- a mere heart of stone.

The fact of evolution is the backbone of biology, and biology is thus in the peculiar position of being a science founded on an improved theory, is it then a science or faith?

We must, however, acknowledge as it seems to me, that a man with all his noble qualities...still bears in his bodily frame the indelible stamp of his lowly origin.