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SCIENCE 



psr. S. Vol. XLII. No. 1081 



fusing two different categories. Kant's gen- 

 eral philosophical conclusions have in any case 

 thrown a quite new light on our conceptions of 

 the physical world, and have taught us that 

 the validity of these conceptions is of a very 

 different nature from what was previously 

 believed. It may be that just as we can not 

 base physics on the purely mathematical con- 

 ceptions of extension, so we can not base biol- 

 ogy on the purely physical conceptions of 

 matter and energy." 



The whole living structure is organized, 

 every part is definitely related to every other 

 part. This is also true of its activity or metab- 

 olism. Thus it has come about that " in deal- 

 ing with life we not only use a whole series of 

 special terms, but these terms appear to belong 

 to a specific general conception which is never 

 made use of in the physical sciences." " The 

 fundamental mistake of the mechanistic physi- 

 ologists of the middle of last century was that 

 they completely failed to realize this. Such 

 processes as secretion, absorption, growth, 

 nervous excitation, muscular contraction, were 

 treated as if each was an isolable physical or 

 chemical process, instead of being what it is, 

 one side of a many-sided metabolic activity, of 

 which the different sides are indissolubly asso- 

 ciated." 



" Our ordinary language as applied to life 

 corresponds to these characteristics. We nat- 

 urally speak of a living organism as an autono- 

 mous active whole, and think of it as such. 

 The idea of its being a mechanism made up 

 of separable parts, and actuated by external 

 causes, is wholly unnatural to us, and becomes 

 more and more unnatural tbe more we know 

 about organisms." 



" The concept we are using is radically 

 different from any physical concept: for in 

 conceiving what is living we do not separate 

 between matter or structure and its activity." 



" If we assume that the conception of the 

 living organism is the fundamental concep- 

 tion of biology, it is clear that the aim of biol- 

 ogy differs entirely from what it would be if 

 the mechanistic theory were accepted. All at- 

 tempts to trace the ultimate mechanism of life 

 must be given up as meaningless." 



On the contrary, the goal of biology must be 

 the description of the organism as an organic 

 unit. This proposition is illustrated by a dis- 

 cussion of the physiology of respiration, and 

 the conclusion is reached that " the idea which 

 gives unity and coherence to the whole of the 

 physiology of respiration is that of the organic 

 determination of the phenomena." And in 

 general by means of this conception " we intro- 

 duce order and intelligibility into biology, 

 whereas there is no such order or intelligibility 

 if the mechanistic theory of life be adopted." 



Finally it is necessary to take account of 

 one other characteristic of the higher organ- 

 isms, of consciousness. Haldane's conclusion 

 upon this point is as follows: 



" We must, it seems to me, draw a sharp and 

 clear distinction between biology, which deals 

 simply with organic life, and psychology, 

 which deals with conscious life or personality. 

 This distinction is similar in general nature 

 to that which I have already endeavored to 

 draw between physics and biology. Just as 

 biology is a more concrete science, nearer to 

 reality than physics and chemistry, so psychol- 

 ogy is a more concrete science than biology. 

 We can abstract from the psychological aspect 

 of a man or animal, and regard him only from 

 the biological aspect. This is, in fact, what we 

 do in physiology. In regard to most of the 

 details of bodily activity there is little need for 

 deliberate abstraction, since the psychological 

 element lies only in the background. But when 

 we come to deal with the bodily parts more 

 immediately concerned in perception and 

 voluntary response the case is very different. 

 Perception, voluntary response, and conscious 

 activity of every kind belong to personality, 

 and therefore can not as such be dealt with 

 scientifically from the merely biological or 

 pliysiological standpoint.. We might as well 

 attempt to establish physics on a basis which 

 totally disregarded the facts on which the con- 

 ceptions of mass and energy are based, as to 

 establish psychology on a merely physiological 

 basis." 



"Physiology deals, and ought to deal, with 

 living organisms just in so far as the observa- 



