THE WONDERS OF LIFE 



ogy, comparative anatomy, and ontogeny, to the hypo- 

 thetical labors of philologists to draw up the genealogical 

 tree of the legendary Homeric heroes. As a matter of 

 fact, I had myself described my imperfect effort as mere- 

 ly a provisional sketch, as a temporary hypothesis that 

 would open the way for later and better research. A 

 single glance at the immense literature of phylogeny 

 to-day shows how much has been done vSince in this 

 province, and how far we have advanced in the estab- 

 lishment of the features of evolution by means of the 

 united labors of numbers of able paleontologists, anat- 

 omists, and embryologists. Ten years ago I attempted, 

 in the three volumes of my Systematic Phylogeny, to 

 give a comprehensive statement of the results attained. 

 My chief aim was, on the one hand, to construct a 

 natural system of organisms on the basis of their an- 

 cestral history, and on the other hand to prove the 

 mechanical character of the phylogenetic process. All 

 the activities of organisms which are at work in the 

 transformation of species and the production of new ones 

 in the struggle for existence may be reduced to their 

 physiological functions — to growth, nutrition, adapta- 

 tion, and heredity; and these again to the mechanics 

 ' ^and chemistry of the plasm. The struggle for life is 

 itself a mechanical process, in which natural selection 

 uses the disproportion between the excess of germs and 

 the restricted means of existence, in conjunction with the 

 variability of species, in order to produce new purposive 

 structures mechanically and without any preconceived 

 design. This teleological mechanicism has no need of a 

 mysterious design or finality; it takes its place in the 

 general order of mechanical causality which controls all 

 the processes in the universe. Natural finality is only a 

 special instance of mechanical causality. The one is 

 subordinate to the other, not opposed to it, as Kant 

 would have it. 



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