Joseph Jacobs

“ Haeckel's contention that science deals with causes and is indeed the only source from which we can get any explanation of the causes of things has been somewhat rudely disturbed by the views of Mach and Ostwald, Kirchhoff and Pearson, all eminent physicists, who are one in declaring that science can only give changes of configuration, rather than explain the causes of such changes. It is rather the modern view that science can only describe, but cannot explain. ”

“ Then, if the whole life history of the branch of the race to which an animal belongs could be traced in its embryology, it would only be one branch of the wide-spreading tree of life that would thus be elucidated. But beyond this lies the fact that the biogenetic law only claims that embryology gives merely an "epitome" of the racial development, and it is easy for the evolutional biologist to get over the missing links in the way by dragging in the principle of condensation. ”

“ He is a monist - that is, he regards the whole universe as the expression of one substance or unifying principles which finds its expression either in matter or in thought, each of which is the aspect of the other. ”

“ As is well known, he contends that there is no means by which the germplasm or reproductive element can be influenced by the experience of the individual, so that we get the paradoxical result that the race must always remain the same, since no means is provided for passing on any change. It is not surprising to find Prof Haeckel somewhat superciliously disregarding the possibilities of such an unevolutional view of evolution. ”

“ Haeckel is for the moment a representative of the opposition of science to religion. But when one examines into the philosophical basis of his anti-religious attitude, it is somewhat curious to find antiquated views and methods of science made the basis of its opposition to religion. ”

“ De Vries has shown that nature itself makes jumps in forming species. One of the most suggestive hints thrown out by Darwin in his general treatment of the problem was the light that comparative embryology would throw upon the development of species, the underlying assumption being that the embryo passes successively through all the stages of development which the race to which it belongs had traversed. ”

“ The subject is rather gruesome, and is not best adapted for public discussion, but its importance and significance for the theory of evolution can scarcely be overrated. Almost all the speculative work of the last twenty years has clustered around it, in particular the researches of Weismann, whose ingenious views are almost entirely concerned with the distinction between that part of the human body which subserves the individual interests, and that which goes toward continuing the race. ”

“ In other words, if this contention were exactly true, a life history of one of the higher vertebrates should repeat the whole biological history of the organic world since life began upon the globe. This is obviously a large order. In the first place, marvelous as has been the progress of microscopy during the nineteenth century, even the minutest of organisms evades any complete analysis owing to its very minuteness. ”

“ As he is naturally concerned to point out the differences between his view and that of the person who has gained credit for it, a considerable amount of space and time is wasted over details that to the readers of the book are somewhat minute, and, to tell the truth, wearisome. ”