• Great problems are now being handled, keeping every thinking man in suspense; the unity or multiplicity of human races; the creation of man 1,000 years or 1,000 centuries ago; the fixity of species, or the slow and progressive transformation of one species into another; the eternity of matter; the idea of a God unnecessary: such are some of the questions that humanity discusses nowadays.

    Address at the "Sorbonne Scientific Soirée" on April 07, 1864. "The Life of Pasteur". Book by René Vallery-Radot, translated by R .L. Devonshire, p. 140, 1902.