NATURE, HISTORY, AND ETHICS 403 



therefore concluded that it must be the sole agency 

 that effects the modification of animals. 



On the other hand we sought to determine the 

 particular processes of animal evolution by means of 

 historical inquiry. For this purpose we used such 

 evidence as the structure of animals, fossil remains, and 

 so on. We were given the right to do so in virtue of 

 natural laws. In this way we succeeded in determining 

 the period — if only approximately — and the locality in 

 which a certain modification of animals must have taken 

 place, and to some extent we were able to follow the 

 course of this transformation. 



The provinces of natural science and psychology are 

 entirely distinct, as the one forms its concepts on 

 phenomena that occupy space and the other does not, 

 but the distinction does not hold in regard to historical 

 investigation. Bodily and mental phenomena are in 

 time, change, pass through stages, and are individual. 



As we have adopted the view that man has animal 

 ancestors, we must trace his mind also to them, though 

 it is at least a lower stage of development in the animals. 

 We saw in the second chapter that, as a matter of fact, 

 man's mental processes are found in a more rudimentary 

 form in the animal. 



As we cannot admit that the mind is formed in any 

 animal out of nothing, we must ascribe psychic phenomena 

 to the protists. We must even go further. We have 

 accepted the view that living things were developed 

 from inorganic matter. Did psychic phenomena begin 

 at once with the appearance of living substance ? That 



