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SCIENCE 



[N. S. Vol. XXXVIII. No. 977 



prehensive and philosophic a grasp of the 

 intricacies of physics, and whose eloquent 

 though sceptical exposition of our laws 

 and processes, and of the modifications en- 

 tailed in them by recent advances, will be 

 sure to attract still more widespread atten- 

 tion among all to whom the rather abstruse 

 subject-matter is sufficiently familiar. I 

 can not say that I find myself in agreement 

 with all that Henri Poincare wrote or spoke 

 in the domain of physics, but no physicist 

 can help being interested in his mode of 

 presentation, and I may have occasion to 

 refer, in passing, to some of the topics with 

 which he dealt. 



And now, eliminating from our purview, 

 as is always necessary, a great mass of hu- 

 man activity, and limiting ourselves to a 

 scrutiny on the side of pure science alone, 

 let us ask what, in the main, is the charac- 

 teristic of the promising though perturbing 

 period in which we live. Different per- 

 sons would give diiferent answers, but the 

 answer I venture to give is — rapid prog- 

 ress, combined with fundamental scepti- 

 cism. 



Rapid progress was not characteristic of 

 the latter half of the nineteenth century — 

 at least not in physics. Fine solid dynam- 

 ical foundations were laid, and the edifice 

 of knowledge was consolidated; but wholly 

 fresh ground was not being opened up, and 

 totally new buildings were not expected. 



In many eases the student was led to believe 

 that the main facts of nature were all known, that 

 the chances of any great discovery being made by 

 experiment were vanishingly small, and that there- 

 fore the experimentalist's work consisted in de- 

 ciding between rival theories, or in finding some 

 small residual effect, which might add a more or 

 less important detail to the theory. — Schuster. 



With the realization of predicted ether 

 waves in 1888, the discovery of X-rays in 

 1895, spontaneous radioactivity in 1896, 

 and the isolation of the electron in 1898, 

 expectation of further achievement became 



vivid; and novelties, experimental, theo- 

 retical and speculative, have been showered 

 upon us ever since this century began. 

 That is why I speak of rapid progress. 



Of the progress I shall say little — there 

 must always be some uncertainty as to 

 which particular achievement permanently 

 contributes to it ; but I will speak about the 

 fundamental scepticism. 



Let me hasten to explain that I do not 

 mean the well-worn and almost antique 

 theme of theological scepticism: that con- 

 troversy is practically in abeyance just 

 now. At any rate the major confiict is 

 suspended; the forts behind which the 

 enemy has retreated do not invite attack; 

 the territory now occupied by him is little 

 more than his legitimate province. It is 

 the scientific allies, now, who are waging 

 a more or less invigorating confiict among 

 themselves, with philosophers joining in. 

 Meanwhile the ancient foe is biding his 

 time and hoping that from the struggle 

 something will emerge of benefit to him- 

 self. Some positions, he feels, were too 

 hastily abandoned and may perhaps be re- 

 trieved; or, to put it without metaphor, it 

 seems possible that a few of the things pre- 

 maturely denied, because asserted on in- 

 conclusive evidence, may after all, in some 

 form or other, have really happened. 

 Thus the old theological bitterness is miti- 

 gated, and a temporizing policy is either 

 advocated or instinctively adopted. 



To illustrate the nature of the funda- 

 mental scientific or philosophic controver- 

 sies to which I do refer, would require 

 almost as many addresses as there are sec- 

 tions of the British Association, or at any 

 rate as many as there are chief cities in 

 Australia; and perhaps my successor in 

 the chair will continue the theme; but, to 

 exhibit my meaning very briefly, I may 

 cite the kind of dominating controversies 

 now extant, employing as far as possible 



