I30 MODERN TENDENCY OF PHYSICAL SCIENCE. 



" Hitherto Rontgen radiation has seemed to belong almost 

 wholly to Physics, whilst Becquerel radiation belonged largely 

 also to Chemistry, to which science our friend the late Dr. 

 Russell's radiation or emanation has always belonged wholly; 

 but now judgment as to the nature of Rontgen rays may have to 

 be regarded as open to revision. 



" Amid this sea of conflicting hypotheses and guesses, what 

 should be our attitude? And how far should we condemn those 

 philosophers who, in their anxiety to stem the tide of materialistic 

 philosophy (in which enterprise I for one am a sympathiser), 

 have tried to throw doubt upon certain well-established and 

 fundamental laws of physics — an enterprise wherein, as in duty 

 bound. T part company with them? 



"I urge that our attitude should be this:— 



" Let us admit that any law applicable to concrete objects 

 (not merely to abstractions), and established by induction on a 

 bnsis of experience, must necessarily be of the nature of a postu- 

 late ; but let us hold some of the postulates as so well established 

 and secure that any argument that would necessitate their over- 

 hauling is ipso facto to that extent discredited, and not to be 

 countenanced unless supported by new and revolutionary facts; 

 and even these new facts we must try to explain in harmony 

 with all well-established laws, rather than as disturbing or nega- 

 tiving them. 



In other words, let us seek to reconcile all new facts with 

 the fundamental laws of physics, applied in a proper manner, 

 until compelled to cast about for some higher generalisation. 

 For in all probability that higher generalisation, when it comes, 

 will be supplementary rather than superseding; and the condi- 

 tions which necessitate its admission will be specifiable and defi- 

 nite when the subject is properly understood. 



Some mathematicians, among them the late Professor 

 Poincare, are willing to give away their kindred subject of 

 Physics by admitting or maintaining that our laws are not im- 

 portant statements of fact, but are only conveniences of expres- 

 sion. And many philosophers seem eager to accept this vicarious 

 generosity at their hands. 



" But such repudiation of our claims and reduction of our 

 life work to insignificance, 1 altogether deprecate. If we are 

 not seeking real truth, if we are only seeking convenience of 

 expression, the science of physics is not the noble structure 

 which I, for one, think it. 



" To take the simplest and most rudimentary example: — 



Are we to suppose that it is only a matter of convenience 

 whether we say that the earth turns on its axis, or that the host 

 of heaven revolves round it once a day? I hold that the one is 

 a genuine and absolute truth, whilst the other is a genuine and 

 absolute falsehood ; and that convenience of expression has 



