July 31, 1903.] 



SCIENCE. 



139 



taken occasion to define with more pre- 

 cision than, perhaps, he has ever done be- 

 fore his view of the possible attitude of 

 scientific inquiry to inorganic nature on the 

 one hand, and to organic on the other. 

 And he has emphasized this in the letter 

 published in your columns to-daj*. 



That -siew is, as I apprehend, this: In 

 the former, he claims for scientific investi- 

 gation the utmost freedom; in the latter, 

 scientific thought is ' compelled to accept the 

 idea of creative power.' That transcends 

 the possibilities of scientific investigation. 

 Weismann defines this to be "the attempt 

 to indicate the mechanism throiigh which 

 the phenomena of the world are brought 

 about. "When this mechanism ceases sci- 

 ence is no longer possible. ' ' Lord Kelvin, 

 in effect, wipes out by a stroke of the pen 

 the whole position won for us by Darwin. 

 And in so doing it can hardly be denied 

 that his present position is inconsistent 

 with the principle laid down in his British 

 As.soeiation address at Edinburgh in 1871 : 



' ' Science is bound by the everlasting law 

 of honor to face fearlessly every problem 

 which can be fairly presented to it. If a 

 probable solution, consistent with the ordi- 

 narj' course of nature, can be found, we 

 must not invoke an abnormal act of creative 

 power. ' ' Among the biologists of the pres- 

 ent day I apprehend that there ai'e few who 

 are prepared to contend that the Darwinian 

 theory is not so consistent. 



It is a common dialectic artifice to state 

 an opponent's position in terms which 

 allow of its being more readily confuted. 

 It is scarcely, however, worthy of Lord 

 Kelvin. What biologist has ever suggested 

 that a fortuitous concourse of atoms 'could 

 make * * * a sprig of moss'? I confess 

 I think that Lord Kelvin's first thoughts 

 were best, and that it is equally absurd to 

 suppose that a crystal could be made in the 

 same Avay. A fortuitous concourse of 



atoms might produce an amorphous mass 

 of matter; but to form a crystal the 'atoms' 

 must be selected and of the same kind, and 

 their concourse is, therefore, not fortuitous. 

 The fact is that the argument from design 

 applies, for what it is worth, as much to a 

 diamond as to a caterpillar. If it is to be 

 rejected in favor of a mechanical explana- 

 tion in the one ease, it is impossible, logic- 

 ally, to maintain it in the other. 



Lord Kelvin quotas Liebig as denjang 

 that 'grass and flowers • • • grew by 

 mei'e chemical forces.' If not, it may be 

 asked, by what do they grow? If growth 

 is to be accounted for by a 'vital principle,' 

 this must be capable of quantitative meas- 

 urement like any other force. If it is 

 physical energy in another form, Liebig 's 

 dictum is futile. If not, organisms are 

 not subject to the principle of conserva- 

 tion of energy-. Yet this principle was 

 first indicated by Mayer, a biologist. 



Physicists, it may be remarked, are not 

 without their own difficulties. But we do 

 not dismiss their conclusions impatiently 

 on that account. Lord Kelvin said that 

 ' ether was absolutely non-atomic ; it was 

 absolutely structureless and homogeneous.' 

 He speaks of it as if it were a definite 

 concrete thing like the atmosphere. But 

 we can not picture to our minds how such 

 a medium can possess elasticity, or how it 

 can transmit undulations. The fact is that 

 the ether is a mere mathematical figment, 

 convenient because it satisfies various for- 

 mula?. As it is only an intellectual concep- 

 tion, we may invest it with any properties 

 we please. The late Professor Clifford 

 once told me that it was harder than steel. 

 I believe it is now thought to be gelatinous. 

 Anyhow, it is nothing more than a working 

 hypothesis, which some day, like phlogis- 

 ton, will only have historic interest. 



W. T. Thiselton-Dyer. 



IvEW, May 4, 1903. 



