NOVEMBEE 4, 1904.] 



SCIENCE. 



593 



of genetic considerations hazardous. Strictly 

 biological considerations furnish reasons of 

 equal weight for caution. For instance, 

 one will hardly deny that the whole sensory 

 apparatus is a striking instance of adapta- 

 tion. Our perceptions of the world would 

 thus appear to be determined by this 

 adaptation, to be instances of adjustment. 

 They might conceivably have been different, 

 and in the case of many other creatiires, 

 the perceptions of the world are undoubt- 

 edly different. All our logical processes, 

 referring ultimately as they do to our 

 perceptions, would thus appear finally to 

 depend on the adaptation exhibited in the 

 development of our sensory apparatus. So- 

 called laws of thought would seem to be but 

 abstract statements or formulations of the 

 results of this adjustment. It would be 

 absurd to suppose that a man thinks in a 

 sense radically different from that in which 

 he digests, or a flower blossoms, or that two 

 and two are four in a sense radically dif- 

 ferent from that in which a flower has a 

 given number of petals. Thinking, like 

 digesting and blossoming, is an effect, a 

 product, possibly a structure. 



I am not at all interested in denying the 

 force of these considerations. They have, 

 to my mind, the greatest importance, and 

 due weight has, as yet, not been given to 

 them. To one at all committed to a unitary 

 and evolutionary view of the world, it 

 must indeed seem strange if thinking itself 

 should not be the result of evolution, or 

 that, in thinking, parts of the world had 

 not become adjusted in a new way. But 

 while I am ready to admit this, I am by 

 no means ready to admit some of the con- 

 clusions for logic and metaphysics which 

 are often drawn from the admission. Just 

 because thought, as a product of evolution, 

 is functional and judgment instrumental, 

 it by no means follows that logic is but a 

 branch of biology, or that knowledge of the 

 world is but a temporaiy adjustment. 



which, as knowledge, might have been 

 radically different. In these conclusions, 

 often drawn with Protagorean assurance, 

 two considerations of crucial importance 

 seem to be overlooked, first, that adapta- 

 tion is itself metaphysical in character, and 

 secondly, that while knowledge may be 

 functional and judgment instrumental, the 

 character of the functioning has the 

 character of knowledge, which sets it off 

 sharply from all other functions. 



It seems strange to me that the admission 

 that knowledge is a matter of adaptation 

 and thus a relative matter, should, in these 

 days, be regarded as in any way destroying 

 the claims of knowledge to metaphysical 

 certainty. Yet, somehow, the opinion wide- 

 ly prevails that the doctrine of relativity 

 necessarily involves the surrender of any- 

 thing like absolute truth. 'All our knowl- 

 edge is relative, and, therefore, only partial, 

 incomplete, and but practically trust- 

 worthy,' is a statement repeatedly made. 

 The fact that, if our development had been 

 different, our knowledge would have been 

 different, is taken to involve the conclusion, 

 that our Imowledge can not possibly dis- 

 close the real constitution of things, that 

 it is essentially conditional, that it is only 

 a mental device for getting results, that 

 any other system of knowledge which would 

 get results equally well would be equally 

 true; in short, that there can be no such 

 thing as metaphysical or epistemological 

 truth. These conclusions do indeed seem 

 strange, and especially strange on the basis 

 of evolution. For while the evolutionary 

 process might, conceivably, have been dif- 

 ferent, its results are, in any case, the re- 

 sults of the process. They are not arbitrary. 

 We might have digested without stomachs, 

 but the fact that we use stomachs in this 

 important process ought not to free us from 

 metaphysical respect for the organ. As M. 

 Rey suggests, in the Revue philosophique 

 for June, 1904, a creature without the sense 



