i;8 COMTE TO BENJAMIN KIDD PART in 



(3) heredity ; (4) variability. The first three factors 

 sum up in the result (a) struggle ; and all four 

 factors taken together give us the final result (?>) 

 selection. The immediate outcome of Darwin's theory 

 as a contribution to science is this, he needs no 

 additional factor. The factors already named suffice 

 (he holds) to account for the further result many 

 distinct living species. As a scientific worker, Darwin 

 simply postulates his small array of causes existing 

 casually alongside of each other. The man of science 

 has no need to search more deeply, and Darwin does, 

 not do so. But, when natural selection is generalised 

 as a philosophical theory, when it is applied to other 

 departments of existence, outside of and above biology, 

 we must raise deeper issues. We must not allow the 

 assumption to pass as matter of course, that the 

 " abstractions," which are legitimate and necessary in 

 special sciences, are facts, or are determining condi- 

 tions of all human thinking. Because you have 

 skilfully dissected the world into a few separate limbs 

 or tissues, and can show exactly how they fit together, 

 it does not follow that no subtle " spiritual bond " 

 has eluded your scalpel. Because you can explain 

 your special problem without asking whether organism 

 and environment, organism and organism, force and 

 force, have any necessary relation to each other beyond 

 the bare fact of coexistence, it does not follow that 

 you have demonstrated the unreality of such a re- 

 lationship. You have assumed its non-existence 

 or rather you have ignored the whole question ; and 

 quite fairly for a special purpose. But you have proved 

 nothing. And the sceptical programme is improbable, 

 perhaps impossible ; " mechanism made absolute ; chance 

 the only nexus between the elements of nature ! " 



