THE CONCEPT OF EVOLUTION 361 



great gaps from their modern descendants. In general, while 

 there are long-lived conservative types, like Lingula, which 

 persist, with little change or none, from age to age, evolution 

 has meant replacement of old by new. 



In many cases what we dimly descry is a vigorous stock 

 from which tentative offshoots arise, which lead to much or 

 to little, while the main branch grows on and, as if it were 

 purified, gives rise to fine fruit. Thus from the early 

 Primate stock there diverged off at various levels New World 

 Monkeys, Old World Monkeys, small Apes and great Apes, 

 leaving a humanoid branch none the worse, to say the least. 



In a concrete way the concept of Evolution means that 

 the present is the child of the past and the parent of the 

 future, that the present-day fauna and flora and all the sys- 

 tem of inter-relations have arisen in a natural knowable 

 way from a preceding state of affairs on the whole somewhat 

 simpler, and that from forms and inter-relations simpler 

 still, and so on backwards till we lose all clues in the thick 

 mist of life's beginnings. 



" As in the development of a fugue," Samuel Butler said, 

 " where when the subject and counter-subject have been an- 

 nounced, there must thenceforth be nothing new, and yet 

 all must be new, so throughout organic nature which is a 

 fugue developed to great length from a very simple subject 

 everything is linked on to and grows out of that which comes 

 next to it in order errors and omissions excepted." 



5. May Evolution Have Been a Process of Analytic 

 Simplifying, not of Synthetic Complexifying 1 ? 



Since the publication of the Origin of Species there 

 have been various outcrops of the idea that the process of 

 evolution may have been not by synthetic complexifying but 



