BIOLOGY AND SOCIOLOGY 73 



at all by the physicist and chemist — the category of 

 mind and mental process. Sir Charles Sherrington, 

 with admirable lucidity, drew for us, in his recent 

 address to the British Association, the problem of 

 the relation between mind and matter as it presents 

 itself to the biologist. 



The great change that has come over science in 

 the last half century, or so it seems to me, is the 

 recognition that mind is not to be explained away as 

 a mere epiphenomenon, but is to be studied as a 

 phenomenon. From this point of view, biology will 

 always be the connecting link between physico- 

 chemical science on the one hand, and psychology 

 on the other. There is every reason to suppose and 

 no reason to doubt that life, which we know to be 

 composed of the same material elements and to work 

 by the same energy as non-living matter, actually 

 arose from it during the evolution of this planet. 

 There is, in the behaviour of the lower organisms, 

 nothing which by itself would make us postulate 

 mind: but in the higher insects, molluscs, and verte- 

 brates, the last in particular, mental process is not 

 only clearly present, but clearly of great biological 

 importance; and finally the mind of man, according 

 to innumerable converging lines of evidence, has 

 evolved from the mind of some non-human mammal. 



The principle of continuity makes us postulate 

 that this new category of phenomena has not sprung 

 up during the course of evolution absolutely de novo, 

 but that it is in some sense universally present in 



