THE HAZARDS OF THE PAST 



ligence has been developed at the expense of in- 

 stinct, and that in the invertebrates instinct has 

 been perfected at the expense of intelHgence. 



Are we not compelled to adopt what is called the 

 monophyletic hypothesis, that is, that our line of 

 descent started from one pair, male and female, 

 somewhere in the vast stretch of geologic or biologic 

 time, and to reason that, had that pair been out of 

 the race, we should not have appeared? 



Can we narrow life to a single point, a single cell, 

 in the past? Was there one and only one first bit of 

 protoplasm? If we were to say that life first ap- 

 peared on the globe in Cambrian times, just what 

 should we mean? That it began as a single point, 

 or as many points? When we say that the primates 

 first appeared in Eocene times, do we mean that 

 one single primate appeared then? If so, what form 

 went immediately before him? This is all a vain 

 speculation. 



Does man presuppose all the vertebrate sub-king- 

 dom? Was he safe as long as one vertebrate form 

 remained? Are his forebears many, and not one 

 pair? Can we think of his ancestry under the image 

 of a tree, and of him as one of the many branches? If 

 so, nothing but the destruction of the tree would have 

 imperiled his appearance, or the lopping off of his 

 particular branch. Probably all such images are 

 misleading. We simply cannot figure to ourselves 

 the tangled course of our biological descent. If 



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