186 THE MECHANISM OF LIFE 



Now quite a considerable fraction of all the " serious " books 

 that have ever been written deal with the question, Have we 

 ideas that exist prior to ordinary experience ? We regard this 

 question as having been finally resolved by Kant in the Critique 

 of Pure Reason, even if it had not been answered in the affirma- 

 tive by the methods of science. There are " ideas " or " cate- 

 gories " that are " innate " in the sense that they are in the 

 human mind before the latter attains experience of the outer 

 world. Perhaps it is more correct to say, with Driesch, that 

 they exist and are awakened by experience. Evidently some- 

 thing is there that makes use of or co-ordinates experience, but 

 from the point of view of this book we prefer to think about 

 modes of mental operation rather than " innate ideas." 



This point of view is actually forced upon us, since we must 

 consider not only the human mind, but also that of the animals 

 other than man. Between the generalised intellect of the highest 

 kind, which was analysed by Kant, and that of the higher animals 

 other than man there exist, even now, almost all possible grada- 

 tions. Further, the gap between the higher mammals and 

 primitive man has been filled, almost in our own day, by the 

 discovery of extinct human races, and below these forerunners 

 of modern man are the lower mammals, the arthropods and other 

 animals, in which we may easily trace the workings of incipient 

 intelligence. We must assume a series of transitions between 

 man and the lower animals both on the physical and the psychical 

 sides, and we must assume, provisionally at all events, that a 

 " Critique of Comparative Reason " may yet be made, and that 

 until it is made the analysis of the human understanding will 

 always be defective. 



A theory of knowledge and a theory of life, says Bergson, are 

 not to be distinguished. What does this mean ? We note, first 

 of all, that theory of life and theory of evolution are one and the 

 same thing. No form of life stands apart and is stable, for, 

 obviously, every one — man, the anthropoid apes, the lower 

 mammals, the arthropods — are phases in an evolutionary flux. 

 There must have been continuity at all times in this flux, for 

 evolution has proceeded by little .steps, or changes, which are 

 usually so small as to appear insensible to ordinary observation. 

 Every one of these little steps is an adaptation — some change of 

 functioning whereby the organism becomes the more able to act 

 ufon the outer world. The variation (or, better, mutation) may 



