INDUCTIONS IMPROPERLY SO CALLED. 



197 



In every way, therefore, it is evident 

 that to explain induction as the col- 

 ligation of facts by means of appro- 

 priate conceptions, that is, conceptions 

 which will really express them, is to 

 confound mere descriptions of the 



different explanations of a phenomenon, 

 may all be true. Of the three theories 

 respecting the motions of the heavenly 

 bodies, he says {Philotophy of Discovery, 

 p. 231) : " Undoubtedly all these explana- 

 tions may be true and consistent with 

 each other, and would be so if each had 

 been followed out so as to show iu what 

 manner it could be made consistent with 

 the facts. And this was in reality in a 

 great measure done. The doctrine that the 

 heavenly bodies were moved by vortices 

 was successfully modified, so that it came 

 to coincide in its results witii the doctrine 

 of an inverse-quadratic centripetal force. 

 .... When this point was reached, the 

 vortex was merely a machinery, well or 

 ill devised, for producing sucli a centripetal 

 force, and therefore did not contradict the 

 doctrine of a centripetal force. Newton 

 himself does not appear to have been averse 

 to explaining gravity by impulse. So little 

 is it true that if one theory be true the 

 other must bo false. The attempt to ex- 

 plain gravity by the impulse of streams of 

 particles flowing tiirough the universe in 

 all directions, which I have mentioned in 

 the Philosophy, is so fur from being incon- 

 sistent with the Newtonian theory, that it 

 is founded entirely upon it. And even with 

 regard to the doctrine that the heavenly 

 bodies move by an inherent virtue, if this 

 doctrine had been maintained in any such 

 way that it was brought to agree with the 

 facts, the inherent virtue must have had 

 its laws determined; and then it would 

 have been found that the virtue had a 

 reference to the central body ; and so the 

 I inherent virtue ' must have coincided in 

 its effect with the N ewtonian force ; and 

 then the two explanations would agree, 

 except so far as the word ' inherent ' was 

 concerned. And if such a part of an earlier 

 theory as this word inherent indicates is 

 found to be untenable, it is of course re- 

 jected in the transition to later and more 

 exact theories, in Inductions of this kind, 

 as well as in what Mr. Mill calls Descrip- 

 tions. There is, therefore, still no validity 

 discoverable in the distinction which Mr. 

 Mill attempts to draw between descriptions 

 like Kepler's law of elliptical orbits, and 

 other examples of induction." 



If the doctrine of vortices had meant, 

 not that vortices existed, but only that the 

 planets moved in the same vianner as if 

 they had been whirled by vortices ; if the 

 hypothesis had been merely a mode of 

 representing the facts, not an attempt to 

 account for them ; if, in short, it had been 

 only a Description, it would, no doubt. 



observed facts with inference from 

 those facts, and ascribe to the latter 

 what is a characteristic property of 

 the former. 



There is, however, between Colliga- 

 tion and Induction a real correlation, 



have been reconcilable with the Newtonian 

 theory. The vortices, however, were not a 

 mere aid to conceiving the motions of the 

 planets, but a supposed physical agent, 

 actively impelling them ; a material fact 

 which might be true or not true, but could 

 not be both true and not true. According 

 to Descartes' theory it was true, according 

 to Newton's it was not true. Dr. Whewell 

 probably means that since the phrases, 

 centripetal and projectile force, do not 

 declare the nature but only the direction 

 of the forces, the Newtonian theory does 

 not absolutely contradict any hypothesis 

 which may be framed respecting the mode 

 of theirproduction. The Newtonian theory, 

 regarded as a mere description of the 

 planetary motions, does not ; but the 

 Newtonian theory as an explanation of them 

 does. For in wliat does the explanation 

 consist? In ascribing those motions to a 

 general law which obtains between all 

 particles of matter, and in identifying this 

 with the law by which bodies fall to the 

 ground. If the planets are kept in their 

 orbits by a force which draws the particles 

 composing them towards every other par- 

 ticle of matter in the solar system, they are 

 not kept in those orbits by the impulsive 

 force of certain streams of matter which 

 whirl them round. The one explanation 

 absolutely excludes the other. Either the 

 planets are not moved by vortices, or they 

 do not move by a law common to all matter. 

 It is impossible that both opinions can be 

 true. As well might it be said that there 

 is no conti-adiction between the assertions, 

 that a man died because somebody kUled 

 him, and that he died a natural death. 



So, again, the theory that the planets 

 move by a virtue inherent in their celestial 

 nature, is incompatible with either of the 

 two others: either that of their being 

 moved by vortices, or that which regards 

 them as moving by a property which they 

 have in common with the earth and all 

 terrestrial bodies. Dr. Whewell says that 

 the theory of an inherent virtue agrees 

 with Newton's when the word inherent is 

 left out, which of course it would be (he 

 says) if "found to be untenable." But 

 leave that out, and where is the theory? 

 The word inherent is the theory. When 

 that is omitted, there remains nothing ex- 

 cept that the heavenly bodies move '' by a 

 virtue," i.e. by a power of some sort, or by 

 virtue of their celestial nature, which 

 directly contradicts the doctrine that ter- 

 restrial bodies fall by the same law. 



If Dr. Whewell is not yet satisfied, any 

 other subject will serve equally well to test 



