526 



THE CAT. 



[CHAP. xv. 



and controlled into that unity which we perceive in each separate 

 living organism. 



All nutrition, growth, and reproduction are normally controlled 

 and ultimately effected by it, no less than all motion, feeling, and 

 cognition. Therefore it is by it that those physical changes are 

 effected which, during the process of individual development, so 

 change the conditions of the matter of the body, as, by degrees, to 

 render it unsuitable for the form actually embodied in it, and to 

 prepare it to receive that form which comes next in the order of 

 evolution. 



16. This is what is really meant by the assertion that the 

 genesis of species takes place mainly through the agency of an 

 internal force,* and this mode of origin may as opposed to the 

 hypothesis of natural selection be fitly termed PSYCHOGENESIS. 



17. But the further question may yet be asked, what de- 

 termines the origin of species by psychogenesis ? What controls 

 and directs the successive evolutions and disappearances of these 

 various "forms" or psychical principles of individuation "forms" 

 which ever arise in due order and succession now, and which we 

 may therefore infer to have arisen in due order and succession 

 through the countless ages of past organic activity ? 



To this question no reply is possible without passing from questions 

 of physical science to the highest problems of philosophy. But no 

 natural object can be fully understood without reference to such 

 problems, and to shrink from explicitly referring to them here, 

 would be a dereliction of scientific duty. The consideration of the 

 action and nature of no cause which there is reason to suppose 

 influences the formation of living creatures, can fitly be omitted 

 from the study of the evolution of any form of life. 



The observer of nature who contents himself with considering 

 external phenomena and does not reflect on his own intellectual 

 powers and the similar powers of his fellow-men such a partial 

 observer of nature may perhaps conceive of the cause thus operating 

 in evolution as unintelligent. He may deem it to be some principle 

 utterly inconceivable by us, pervading all space and enduring 

 through all time, yet devoid of consciousness and will. He may 

 deem it to be a force incapable of apprehending what it produces, 

 but which is at the same time the origin of all law, all beauty, and 

 all intelligence. 



But let us see what such a conception really means. It is 

 admitted that we cannot transcend experience. We cannot then 

 imagine a first cause save in terms the elements of which are within 



* This conception, put forward in 

 "The Genesis of Species," seems to be 

 now practically admitted, r even by the 

 author of "The Origin of Species," for 

 the latter has come to admit that ' ' abrupt, 

 strongly marked changes," may occur 

 "neither beneficial nor injurious " to the 

 creature which exhibits them, produced 



by "unknown agencies" lying deep in 

 "the nature of the organism/" It is 

 hardly necessary to point out that with 

 respect to such developments, "Natural 

 Selection " must be absolutely impotent. 

 Upon such changes it cannot possibly 

 exert any influence whatever. 



