326 INDUCTION. 



induction left for Kepler to make, nor did he make any further 

 induction. He merely applied his new conception to the facts 

 inferred, as he did to the facts observed. Knowing already 

 that the planets continued to move in the same paths ; when 

 he found that an ellipse correctly represented the past path, 

 he knew that it would represent the future path. In finding 

 a compendious expression for the one set of facts, he found 

 one for the other : but he found the expression only, not the 

 inference; nor did he (which is the true test of a general 

 truth) add anything to the power of prediction already pos- 



4. The descriptive operation which enables a number 

 of details to be summed up in a single proposition, Dr. 

 Whewell, by an aptly chosen expression, has termed the 

 Colligation of Facts. In most of his observations concerning 

 that mental process I fully agree, and would gladly transfer 

 all that portion of his book into my own pages. I only think 

 him mistaken in setting up this kind of operation, which 

 according to the old and received meaning of the term, is not 

 induction at all, as the type of induction generally ; and laying 

 down, throughout his work, as principles of induction, the 

 principles of mere colligation. 



Dr. Whewell maintains that the general proposition which 

 binds together the particular facts, and makes them, as it 

 were, one fact, is not the mere sum of those facts, but some- 

 thing more, since there is introduced a conception of the 

 mind, which did not exist in the facts themselves. "The 

 particular facts," says he,* " are not merely brought together, 

 but there is a new element added to the combination by the 

 very act of thought by which they are combined. . . . When 

 the Greeks, after long observing the motions of the planets, 

 saw that these motions might be rightly considered as pro- 

 duced by the motion of one wheel revolving in the inside of 

 another wheel, these wheels were creations of their minds, 

 added to the facts which they perceived by sense. And even 



* Novum Organum Renovatum, pp. 72, 73. 



