IN 1859 Darwin's "Origin of Species" appeared,. and the struggle was on. In 1862 Huxley began his active participation in it, a participation brilliantly maintained until his death. In 1863 Haeckel, before an association of German naturalists in Stettin, declared the Darwinian theory to be the greatest step forward in the study of life that had been taken in modern times; and he prophesied for it the same importance in the understanding of organic nature that Newton's law of gravitation had had in the understanding of the inorganic world. Steadily, since that day, Haeckel has been carrying on the fight for Darwinism and its corollaries.
Of greatest popular interest among these corollaries or logical conclusions and most opposed by all tradition and ecclesiastic and metaphysical authority are, first, the direct descent of man from the lower animals, with all his attributes mental and spiritual as well as physical; and, second, a strictly monistic conception of the world as opposed to the old strongly-established dualistic conception. As Huxley was in England, so Haeckel is in Germany, the special battling champion of the theory of descent and its conclusions. And even more conspicuously than Huxley, Haeckel has maintained and fought for the revolutionary and "irreligious" logical conclusions of the full acceptance of the theory of cosmic and organic evolution.
Such a complete acceptance unites God and nature into an indissoluble unity, even as it does matter and force, body and soul. It leaves no place in one's philosophy for a supernatural, creating God, or for a distinct and peculiar vital force or for a personal immortality of the soul. It accepts completely the cosmic and organic evolution explanation of the earth and its life, holding that life originated on the cooling earth naturally out of non-living materials "by catalysis from colloidal carbohydrogen combinations," and that man is, in his entirety, the outcome of biological transformation, his nearest relatives among living animals kinds being the tailless apes.
Obviously the man who should stand as the champion in poetic, metaphysical, religious Germany of such a Weltansschauung must be a man of unusual strength to stand at all, much less to make head against the great forces that would necessarily bar and dispute his way; indeed would combine to overwhelm and trample him under foot. Haeckel has