388 OPERATIONS SVBSIDIARY TO INDUCTION. 



corresponds to as many points of an ellipse, the places themselves 

 agree in being situated in that ellipse. We have, therefore, by means 

 of the description, obtained the requisites for an induction by the 

 Method of Agreement. The successive observed places of the earth 

 beino- considered as effects, and its motion as the cause w^hich produces 

 them, we find that those effects, that is, those places, agree in the cir- 

 cumstance of being in an ellipse. We conclude that the remaining 

 effects, the places which have not been observed, agree in the same 

 circumstance, and that the laiv of the motion of the earth is motion in 

 an ellipse. 



The Colligation of Facts, therefore, by means of hypotheses, or, as 

 Mr. Whewell prefers to say, by means of Conceptions, instead of being, 

 as he supposes. Induction itself, takes its proper place among opera- 

 tions subsidiary to Induction. All Induction supposes that we have 

 previously compared the requisite number of individual in^ances, and 

 ascertained in what circumstances they agree ; the Colligation of Facts 

 is no other than this preliminaiy operation : and the proper office of 

 " clear and appropriate ideas," on the necessity of which Mr. Whewell 

 has said so much, is to enable us to perform this operation correctly. 

 When Kepler, after vainly endeavoring to connect the observed places 

 of a planet by various hypotheses of circular motion, at last tried the 

 hypothesis of an ellipse and found it answer to the phenomena, what 

 he really attempted, first unsuccessfully and at last successfully, was to 

 discover the circumstance in which all the observed positions of the 

 planet agreed. And when he in like manner connected another set of 

 obsei'ved facts, the periodic times of the different planets, by the prop- 

 osition that the squares of the times are proportional to the cubes of 

 the distances, what he did was simply to ascertain the property in 

 which the periodic times of all the different planets agreed. 



Since, therefore, all that is true and to the pui-pose in Mr. Whewell's 

 doctrine of Conceptions might be fully expressed by the more familiar 

 term Hypothesis ; and since his Colligation of Facts by means of ap- 

 propriate Conceptions, ic but the ordinary process of finding by a 

 comparison of phenomena, in what consists their agreement or resem- 

 blance ; I would willingly have confined myself to those better under- 

 stood expressions, and persevered to the end in the same abstinence 

 which I have hitherto observed from all ideological discussions ; con- 

 sidering the mechanism of our thoughts to be a topic distinct from and 

 irrelevant to the principles and rules by which the ti'ustworthiness of 

 the results of thinking is to be estimated. Since, however, a work of 

 such high pretensions, and, it must also be said, of so much real merit, 

 has rested the whole theory of Induction upon such ideological con- 

 siderations, it seems necessary for others who follow, to claim for 

 themselves and their doctrines whatever position may properly belong 

 to them on the same metaphysical gioujid. And this is the object of 

 the succeeding chapter. 



