F^Fresult 



UXLEY, AND THE PROBLEM OF THE NATURALIST 39 



'result from the nature and disposition of its component molecules, 

 I can find no intelligible ground for refusing to say that the prop- 

 erties of protoplasm result from the nature and disposition of its 

 molecules." 



I know no reason why any one should "refuse to say" this, 

 except that "the assertion which outstrips evidence is a crime." 

 When it has been proved, I, for one, shall say it cheerfully ; but I 

 cannot forget that we have been taught for two thousand years and 

 more that life is not a property of the physical basis like the prop- 

 erties of water, but a relation, an adjustment between the properties 

 of the organism and of those of the environment, between the 

 changes which take place in the body and those which go on in the 

 world around it ; that this adjustment serves to promote the welfare 

 of the species, and that we know nothing comparable to it in water 

 or in anything else except living beings, and their products, such 

 as watches, and spiders' webs, and birds' nests. 



The author of our oldest book on zoology opens it with the 

 following statement of its purpose : — 



" To say what are the ultimate substances out of which an animal 

 is formed ... is no more sufficient than would be a similar account 

 in the case of a couch. For we should not be content with saying 

 that the couch was made of bronze or of wood, or whatever it might 

 be, but should try to describe its design or mode of composition in 

 preference to the material. ... It is plain that the teaching of 

 the old physiologists is inadequate, and that the true method is to 

 state what the definite characters are that distinguish the animal 

 as a whole. ... In fact, to proceed in exactly the same way as we 

 should do if we were giving a complete description of a couch." ^ 



If this is true, if life is not a property like those of water, but 

 an adjustment between properties, it must be clear that no amount 

 of knowledge of any properties of the physical basis except the 

 property of fitness can ever give us a science of life, although it 

 must be equally clear that knowledge of all its properties is a 

 necessary condition for progress. My comment on the essay " On 

 the Physical Basis of Life " is that, while I fully agree with it, 

 I hold with Aristotle that it is "inadequate," although I am quite 

 prepared to admit the possibility that this inadequacy may be due 



1 Aristotle, " Parts of Animals," I. i. 



