The fear of life, the fear of burdens and of duties, of annoyances and of catastrophes! The fear of life, which makes us, through dread of its sufferings, refuse its joys. Ah! I tell you, this cowardliness enrages me; I cannot forgive it. We must live - live a complete life - live all our life.

If you shut up truth, and bury it underground, it will but grow.

I believe that the future of humanity is in the progress of reason through science. I believe that the pursuit of truth, through science, is the divine ideal which man should propose to himself.

In my view you cannot claim to have seen something until you have photographed it.

Perfection is such a nuisance that I often regret having cured myself of using tobacco.