370 THE CONCEPT OF EVOLUTION 



oal tree in very ancient times, of which there is relatively 

 little fossil-record. In regard to some more recent origina- 

 tions, such as elephants and horses, the pedigree is very v^ell 

 known. 



In the second place, apart from the general formula, little 

 light has been thrown on the factors at work in the establish- 

 ment of most of the great new departures. How little we 

 can say of the factors operative in the emergence of Birds 

 from a Saurian stock or of Man from a Primate stock! 

 Some people talk as if they believed that one had only to 

 mutter the word ' Evolution ' for difficulties to disappear. 



In the third place, there is the general and central diffi- 

 culty that we know so very little — serious aetiology practi- 

 cally dates from Darwin — in regard to the causes of varia- 

 tion itself, on which all evolution depends. 



§ 7. Difficulties in the Way of Concrete Evolution Theory 

 Lead to Hypotheses of Transcendental Underpinning. 



The difficulty of giving a concrete account of the evolu- 

 tion of a phylum such as Vertebrates, or of an organ like 

 the eye, or of a phenomenon like migration, is great ; but 

 it "will probably disappear as knowledge grows. It must 

 be remembered, however, that the difficulty led so distin- 

 guished a pioneer as Alfred Russel Wallace and some others 

 with him to postulate the operation of spiritual influxes 

 at particularly critical stages in the evolution, as in the 

 origin of man's mathematical, musical, and artistic faculties, 

 or in the introduction of consciousness, or in the emergence 

 of organisms themselves. Wallace spoke of '' different de- 

 grees of spiritual influx ", as it were welling up from '' an 

 unseen universe — a world of spirit, to which the world of 

 matter is altogether subordinate ". . . . ^' A change in essen- 



