SUBJECTIVE AND OBJECTIVE METHODS 



the time by which to oppose it. Then came the 

 necessity for verification ; " and by this criterion 

 GaHleo^ ascertained that the first-named con- 

 ception — the one which had been held by the 

 ancients — was erroneous, " and although the 

 alternative conception which replaced it was not 

 more intelligible, it had the supreme advantage 

 of being a more accurate description of the order 

 of nature." Therefore " in all verifiable cases 

 we dare not be confident that an explanation is 

 true because its truth seems possible. Our con- 

 ceptions of possibility are too contingent to form 

 a secure ground of deduction. Thus, to Galileo, 

 it at first seemed possible that velocity must be 

 proportional to space, because, in so conceiving 

 it, he had not distinctly visible to his mind all 

 the elements of the problem ; in other words, 

 all the possibilities." But when, in the process 

 of verification the omitted elements of the case 

 were brought before the mind, he discovered 

 " that the seeming possibiHty was a fiction." 

 The other alternative, that velocity is propor- 

 tional to time, was found to be the true one, and 

 the only one which could withstand the appli- 

 cation of the test of truth. The counter-propo- 

 sition, that the velocity is not proportional to 



1 [On Galileo's procedure one may compare the recent 

 critical discussion of Mach, in his History of the Principles 

 of Mechanics, chap. ii. § 3 sqq.] 



159 



