We may confidently come to the conclusion, that the forces which slowly and by little starts uplift continents, and that those which at successive periods pour forth volcanic matter from open orifices, are identical.

I cannot see ... evidence of design and beneficence ... There seems to me too much misery in the world.

On the theory of natural selection we can clearly understand the full meaning of that old canon in natural history, “Natura non facit saltum.” This canon, if we look only to the present inhabitants of the world, is not strictly correct, but if we include all those of past times, it must by my theory be strictly true.

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?

The tree of life should perhaps be called the coral of life, base of branches dead; so that passages cannot be seen-this again offers contradiction to constant succession of germs in progress.

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.

I think it inevitably follows, that as new species in the course of time are formed through natural selection, others will become rarer and rarer, and finally extinct. The forms which stand in closest competition with those undergoing modification and improvement will naturally suffer most.