HYPOTHESIS 135 



goes on constructing and testing hypotheses based on fundamental assump 

 tions which he knows to be metaphysically untenable, he must surely know 

 that, whatever practical utility they may possess as possible aids to experiment, 

 they cannot be true theories of reality, or ever form a constituent portion of 

 science proper, of truth, whether physical or metaphysical. The assumptions 

 Mr. Joseph has in mind are probably, among others, &quot; the independent exist 

 ence of matter, the action of one independent thing on another, the produc 

 tion of a conscious state by a process in a physical organism &quot; : * these he 

 regards as &quot; unable to resist metaphysical criticism,&quot; 2 and as affording, there 

 fore, only a provisional validity to the scientific hypotheses and explanations 

 based upon them. No doubt, if such metaphysical theses are held as unproven 

 assumptions, the scientific theories based upon them will be only provisional. 

 For instance, the scientific theories based upon the hypothesis of an ether- 

 medium in space can be true only on the assumption that there is no actio in 

 distans in the actual physical universe. But it is one thing to accept any such 

 fundamental assumption provisionally, and proceed to build upon it, and an 

 other thing altogether to regard such an assumption as &quot; metaphysically unten 

 able &quot;. We take this latter expression as equivalent to rationally indefensible; 

 and, obviously, to build on such an assumption would be worse than illogical, 

 for it would be irrational. Mr. Joseph s difficulty, from the point of view 

 of metaphysics, against such assumptions of science as those referred to, 

 seems to be that they &quot; are all unintelligible &quot; 3 . But this brings us again to 

 the question referred to in connexion with the principles of Sufficient Reason 

 and Uniformity of Nature : What is the criterion of intelligibility ? Is that 

 alone intelligible which is imaginable after mechanical analogies, and de- 

 scribable in terms of the purely quantitative concepts of mathematics and 

 dynamics ? and is it only such laws and principles that are to be recognized 

 as scientific ? 4 Such a restricted conception of the domain of the &quot; intelligible &quot; 

 and the &quot; scientific &quot; we regard as a good example of those metaphysical as 

 sumptions which are fairly open to serious criticism. 



229. THE R6LE OF ANALOGY IN VERIFICATION : ULTIMATE 

 SYSTEMATIC CONCEPTIONS. The &quot; cause &quot; which forms the object 

 of a scientific hypothesis need not, then, be itself a phenomenon. 

 Further, it need not be an agency which is already known as such 

 to be operative elsewhere in nature : otherwise no new natural 

 agency could be discovered by way of hypothesis. But it must 

 be conceived to bear some analogy or resemblance to some such 

 known agency. The reason of this requirement is not difficult 

 to find. It is only in so far as we conceive our supposed cause 

 to be analogous in its modus operandi to some known cause or 

 other, that we can infer anything as to the conduct of the former 

 in this or that particular set of circumstances. And it is only by 

 observing such operation experimentally, if necessary and pos- 



l op. cit., p. 469. *ibid. ibid. 



4 C/. WARD, op. cit., i., pp. 119, 120. 



