258 SCIENCE AND PHILOSOPHY OF THE ORGANISM 



special fields ; but the compounds it deals with at the 

 same time may be said to have originated historically also, 

 though not, of course, by a process of propagation. It is 

 evident at once that the geological conditions of very early 

 times prohibited the existence of certain chemical com- 

 pounds, both organic and inorganic, which are known at 

 present. None the less these compounds occupy their 

 proper place in the system. And there may be many 

 substances theoretically known to chemical systematics 

 which have never yet been produced, on account of the 

 impossibility of arranging for their proper conditions of 

 appearance, and nevertheless they must be said to " exist." 

 "Existence," as understood in systematics, is independent 

 of special space and of special time, as is the existence of 

 the laws of nature : we may speak of a Platonic kind of 

 existence here. Of course it does not contradict this sort 

 of ideal existence if reality proper is added to it. 



Thus the problem of systematics remains, no matter 

 whether the theory of descent be right or wrong. There 

 always remains the question about the totality of diversities 

 in life : whether it may be understood by a general prin- 

 ciple, and of what kind that principle would be. As, in 

 fact, it is most probably by history, by descent, that 

 organic systematics is brought about, it of course most prob- 

 ably will happen some day that the analysis of the causal 

 factors concerned in the history will serve to discover the 

 principle of systematics also. 



Let us now glance at the different kinds of hypotheses 

 which have been established in order to explain how the 

 descent of the organisms might have been possible. We 

 have seen that the theory of transformism alone is not 



