HYPOTHESIS 133 



measurable phenomena, in which they are supposed to be operative, are 

 equally amenable to observation and experiment, whether the hypothetical 

 &quot; causes &quot; be conceived as &quot; properties,&quot; &quot; forces,&quot; &quot; affinities,&quot; &quot; qualities ; &quot; 

 or as &quot; atoms,&quot; &quot; electrons &quot; &quot; vortices,&quot; &quot; undulations,&quot; etc. Quantitative 

 values may be assigned to such factors, by whatever names we call the latter. 

 Since they are supposed to be factors operative in material phenomena, there 

 must be a quantitative aspect in their modits operandi ; only we must not forget 

 that this is not their sole aspect, and that we have not &quot; explained &quot; the facts 

 fully by &quot; calculating &quot; the measiirable aspects of these factors. Yet this is 

 likely to be forgotten by scientists who are influenced by the empirical philo 

 sophy. Their tendency naturally is to assume that &quot; all perceptible facts are 

 measurable &quot; 1 in terms of material masses and mechanical motions, and that 

 science can attain to nothing that is not thus measurable. But, for instance, 

 exhibitions of &quot; talent, prudence or self-denial &quot; 2 are perceptible facts. Yet, 

 surely, their &quot; magnitude &quot; cannot be measured by any mechanical standard. 

 The &quot; attainment of precise mathematical law &quot; is a proper ideal for those de 

 partments of research whose laws are capable of assuming &quot; the form of pre 

 cise quantitative statement &quot; ; 3 but to assume that all reality is thus quantita 

 tively measurable, and that exact measurement exhausts all we can know about 

 it, is utterly unjustifiable in point of method, as well as being erroneous in fact. 

 An unfortunate outcome of this tendency has been already instanced (201, 224, 

 cf. p. 141) in the hopeless attempts of some scientists and philosophers to ex 

 plain all the phenomena of the universe on the hypothesis that they are all 

 ultimately reducible to mechanical motions of atoms of matter, a supposition 

 which has absolutely nothing to recommend it but its excessive simplicity. 4 

 Of course, the physical scientist as such may confine himself to the conception 

 and verification of hypotheses that are empirically verifiable, hypotheses about 

 the proximate, phenomenal antecedents of this or that series or group or order 

 of phenomena ; he may abstain from philosophizing, from seeking the ulti 

 mate causes of all physical phenomena : in which case he will have no occa 

 sion to &quot; invoke the agency of beings whose existence cannot be empirically 

 verified,&quot; 5 i.e. beings like angels, spiritual souls, human free-will, God for 

 whose modus operandi known physical agencies and laws furnish no analogy. 

 He may abstract from the influence of such agencies until he reaches the point 

 at which mere physical antecedents begin to appear insufficient or unsatisfac 

 tory for the explanation of his facts. Up to this point, being concerned with 

 proximate causes, he has no need to inquire into ultimate causes : hence, as a 



tr.), ch. xii., pp. 213 sqq., and Introduction by Professor LARMOR, pp. xiv.-xvi. An 

 instructive illustration of the British frame of mind is to be found in a passage 

 from one of Lord Kelvin s lectures at the Johns Hopkins University (quoted by 

 DUHEM, op. cit., p. 194, from the author s Lectures on Molecular Dynamics, p. 132; 

 also by WARD, op. cit., i., p. 119, from Nature, vol. xxxi. (1885), p. 603 : &quot; I never 

 satisfy myself till I can make a mechanical model of a thing. If I can make a 

 mechanical model I can understand it. As long as I cannot make a mechanical 

 model all the way through, I cannot understand. . . .&quot; As to which Dr. Ward 

 pertinently asks: &quot; Why must mechanism all the way through be the one and 

 only means of intelligibility ? &quot; (op. cit., p. 120). 



1 WELTON, op. cit., ii., p. 160. ibid., p. 161. 3 ibid. 



4 Cf. WELTON, op. cit., ii., p. 209. 5 JOSEPH, op. cit., p. 429. 



