The claim to originality made so distinctly in the opening sentences of the" Origin of Species" is repeated in a letter to Professor haeckel, written October 8, 1864, and giving an account of the development of his belief in descent with modification.
"Luck or Cunning?"
Samuel Butler
On the other hand, some devoted young Socialists of my acquaintance have read haeckel and Dietzgen, and adopted the dogma that matter is the first cause, and that all things have grown out of it and return to it; they have seen that the brain decays after death, they declare that the soul is a function of the brain-and because of such theories they deliberately reject the most powerful modes of appeal whereby men can be swayed to faith in human solidarity.
"The Book of Life: Vol. I Mind and Body; Vol. II Love and Society"
Upton Sinclair
haeckel has but done tardy justice in his discovery of and testimony to the genius of Lamarck.
"The Mechanism of Life"
Stéphane Leduc