His theories of evolution hold a different position. Darwin's theory has now been so greatly modified, as much by his supporters as by his opponents, that it cannot be said any longer to hold the field as he first presented it; and Butler's attitude has been in a manner justified. But this change has been accomplished not by the acceptance of Butler's views but by the work of experimental biologists. He did, in fact, offer many general principles, some well founded, some mistaken, all stimulating, for the consideration of practical workers; and it would not be possible to assert, without an exhaustive enquiry into the history of the matter, that his writings have had no influence on the development of science. But Charles Darwin and his followers were practical men--men no doubt with faults, with the intolerance and impatience of the laity that are often to be found in the scientific investigator. It is not hard to see why they received Butler with tepid interest, and finally ignored him when he forsook their path of enquiry. For they did ignore him: they did not, as he supposed, conspire to silence him. He seems to have believed that Darwin was a sort of Anti-Christ malevolently determined to force on humanity a diabolical belief of his own invention; and he was only too ready to suspect him of unscrupulous dealing and machinations. When he conceived that Darwin had engineered an attack on him, though he obtained an expression of regret for an accident, he flung violently into print, and did, though he remained ignorant of the fact, get from Darwin and his friends the attention as an enemy which they would not bestow on him as a scientist. His letter to the _Athenæum_ seriously perturbed Darwin, who drafted two replies to it, and submitted them for advice to the members of his family and to Professor Huxley. The advice given was against replying; and Butler was accordingly confirmed in his opinion. But this was an opinion which a less suspicious man would have been slower in forming and readier to discard.