INDUCTIONS IMPROPERLY SO CALLED. 335 



them, is to confound mere description of the observed facts 

 with inference from those facts, and ascribe to the latter what 

 is a characteristic property of the former. 



between the assertions, that a man died because somebody killed 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 

 terrestrial bodies fall by the same law. 



If Dr. Whewell is not yet satisfied, any other subject will serve equally well 

 to test his doctrine. He will hardly say that there is no contradiction between 

 the emission theory and the undulatory theory of light ; or that there can be 

 both one and two electricities ; or that the hypothesis of the production of 

 the higher organic forms by development from the lower, and the supposition 

 of separate and successive acts of creation, are quite reconcileable ; or that the 

 theory that volcanoes are fed from a central fire, and the doctrines which 

 ascribe them to chemical action at a comparatively small depth below the earth's 

 surface, are consistent with one another, and all true as far as they go. 



If different explanations of the same fact cannot both be true, still less, 

 surely, can different predictions. Dr. Whewell quarrels (on what ground it is 

 not necessary here to consider) with the example I had chosen on this point, 

 and thinks an objection to an illustration a sufficient answer to a theory. 

 Examples not liable to his objection are easily found, if the proposition that 

 conflicting predictions cannot both be true, can be made clearer by any examples. 

 Suppose the phenomenon to be a newly -discovered comet, and that one astro- 

 nomer predicts its return once in every 300 years another once in every 400 : 

 can they both be right ? When Columbus predicted that by sailing constantly 

 westward he should in time return to the point from which he set out, while 

 others asserted that he could never do so except by turning back, were both he 

 and his opponents true prophets ? Were the predictions which foretold the 

 wonders of railways and steamships, and those which averred that the Atlantic 

 could never be crossed by steam navigation, nor a railway train propelled ten 

 miles an hour, both (in Dr. Whewell's words) "true, and consistent with one 

 another" ? 



Dr. Whewell sees no distinction between holding contradictory opinions on 

 a question of fact, and merely employing different analogies to facilitate the 

 conception of the same fact. The case of different Inductions belongs to the 

 former class, that of different Descriptions to the latter. 



