Ernst Haeckel

The real cause of personal existence is not the favor of the Almighty, but the sexual love of one's earthly parents.

Both of these branches of evolutionary science, are, in my opinion, in the closest causal connection; this arises from the reciprocal action of the laws of heredity and adaptation.

I'm quite content to spend my life helping young people find themselves. I've had my fill of politics.

Whoever grows angry amid troubles applies a drug worse than the disease and is a physician unskilled about misfortunes.

We were making the first step out of the age of chemistry and physics, and into the age of biology.