The aim of science is to discover and illuminate truth. And that, I take it, is the aim of literature, whether biography or history or fiction. It seems to me, then, that there can be no separate literature of science.

We have been troubled about the world, and had almost lost faith in man; it helps to think about the long history of the earth, and of how life came to be. And when we think in terms of millions of years, we are not so impatient that our own problems be solved tomorrow.

I like to define biology as the history of the earth and all its life — past, present, and future. To understand biology is to understand that all life is linked to the earth from which it came; it is to understand that the stream of life, flowing out of the dim past into the uncertain future, is in reality a unified force, though composed of an infinite number and variety of separate lives.

Any concept of biology is not only sterile and profitless, it is distorted and untrue, if it puts its primary focus on unnatural conditions rather than on those vast forces not of man's making that shape and channel the nature and direction of life.