ch. v. THE TWO METHODS. 11) 



planets and the " unnatural " variations of that motion as 

 residual facts which needed to be explained by a verifiable 

 hypothesis. Since the planets are deflected at every instant 

 from the rectilinear paths in which their own momentum 

 would for ever carry them, there must be some unknown 

 force acting in composition with their momentum. What i a 

 that unknown force ? That it was the same as the force 

 which causes apples to fall, that it varied in amount in an 

 inverse ratio to the square of the distance between the sun 

 and the planet, and would therefore cause acceleration or 

 retardation of velocity according as the planet in its elliptic 

 path approached or receded from the sun, — all this was a 

 most brilliant hypothesis, alleging no un verifiable agency, 

 disposing of the unexplained residual phenomena, and 

 making the Keplerian order of conceptions completely con- 

 gruous. According to the subjective method, this was quite 

 enough. And doubtless if Newton's mind had been con- 

 structed like Hegel's he would at once have announced his 

 discovery on the strength of its presumed subjective necessity, 

 and would have left it for some other more patient inquirer to 

 verify its truth. But Newton, rigorously adhering to the 

 objective method, saw that this was not enough. No matter 

 how perfectly congruous the subjective order of conceptions 

 may be in itself, it must be confronted with the observed 

 order of phenomena and be shown to be congruous with 

 that. According to the hypothesis the moon must be 

 deflected on the average fifteen feet each minute from its 

 natural rectilinear path. But Newton's own observations 

 showed that this is not the case : the moon is deflected 

 thirteen feet in each minute, and thus was revealed a 

 discrepancy between the order of conceptions and the order 

 of phenomena. It must ever be regarded as a truly sublime 

 illustration of the exalted scientific character of Newton's 

 intellect, that in an age when the inexorable requirements of 

 scientific method were generally so little understood, he laid 



