I. Haeckel and His Opponents

[^10]: Other opponents of Haeckel. Here we can only speak of such objections to Haeckel's doctrines as are, to a certain extent, typical and have their origin in antiquated, although still always influential, circles of thought. The numerous “refutations” of Haeckel, which present themselves merely as variants of the main objections cited, have to be left unnoticed equally with those which Haeckel himself has disposed of in his book on Die Welträtsel, by saying to these valiant warriors, “Acquire by a diligent five years' study of natural science, and in particular of anthropology (especially the anatomy and the physiology of the brain!), that indispensable empirical prior knowledge of the facts, which you still lack entirely.”