22 INDUCTION. 



chance) that even an erroneous interpretation which accorded 

 with all the visible parts of the inscription would accord also 

 with the small remainder; as would he the case, for example, 

 if the inscription had heen designedly so contrived as to admit 

 of a double sense. I assume that the uncovered characters 

 afford an amount of coincidence too great to be merely casual : 

 otherwise the illustration is not a fair one. No one supposes 

 the agreement with the phenomena of light with the theory of 

 undulations to be merely fortuitous. It must arise from the 

 actual identity of some of the laws of undulations with some 

 of those of light : and if there be that identity, it is reasonable 

 to suppose that its consequences would not end with the 

 phenomena which first suggested the identification, nor be 

 even confined to such phenomena as were known at the time. 

 But it does not follow, because some of the laws agree with 

 those of undulations, that there are any actual undulations ; 

 no more than it followed because some (though not so many) 

 of the same laws agreed with those of the projection of 

 particles, that there was actual emission of particles. Even 

 the undulatory hypothesis does not account for all the pheno- 

 mena of light. The natural colours of objects, the compound 

 nature of the solar ray, the absorption of light, and its 

 chemical and vital action, the hypothesis leaves as mysterious 

 as it found them ; and some of these facts are, at least appa- 

 rently, more reconcileable with the emission theory than with 

 that of Young and Fresnel. Who knows but that some third 

 hypothesis, including all these phenomena, may in time leave 

 the undulatory theory as far behind as that has left the theory 

 of Newton and his successors ? 



To the statement, that the condition of accounting for all 

 the known phenomena is often fulfilled equally well by two 

 conflicting hypotheses, Dr. Whewell makes answer that he 

 knows " of no such case in the history of science, where the 

 phenomena are at all numerous and complicated."* Such an 

 affirmation, by a writer of Dr. Whewell's minute acquaintance 

 with the history of science, would carry great authority, if he 



* P. 271. 



