INDUCTIONS IMPROPERLY SO CALLED. 331 



sent occasion we have chiefly to distinguish this process of 

 Colligation from Induction properly so called ; and that the 

 distinction may he made clearer, it is well to advert to a 

 curious and interesting remark, which is as strikingly true of 

 the former operation, as it appears to me unequivocally false of 

 the latter. 



In different stages of the progress of knowledge, philoso- 

 phers have employed, for the colligation of the same order of 

 facts, different conceptions. The early rude observations of 

 the heavenly bodies, in which minute precision was neither 

 attained nor sought, presented nothing inconsistent with the 

 representation of the path of a planet as an exact circle, having 

 the earth for its centre. As observations increased in accuracy, 

 and facts were disclosed which were not reconcileable with this 

 simple supposition ; for the colligation of those additional 

 facts, the supposition was varied ; and varied again and again 

 as facts became more numerous and precise. The earth was 

 removed from the centre to some other point within the circle ; 

 the planet was supposed to revolve in a smaller circle called 

 an epicycle, round an imaginary point which revolved in a circle 

 round the earth : in proportion as observation elicited fresh 

 facts contradictory to these representations, other epicycles and 

 other excentrics were added, producing additional complica- 

 tion; until at last Kepler swept all these circles away, and 

 substituted the conception of an exact ellipse. Even this is 

 found not to represent with complete correctness the accurate 

 observations of the present day, which disclose many slight 

 deviations from an orbit exactly elliptical. Now Dr. Whewell 

 has remarked that these successive general expressions, though 

 apparently so conflicting, were all correct : they all answered 

 the purpose of colligation ; they all enabled the mind to repre- 

 sent to itself with facility, and by a simultaneous glance, the 

 whole body of facts at the time ascertained : each in its turn 

 served as a correct description of the phenomena, so far as the 

 senses had up to that time taken cognizance of them. If a 

 necessity afterwards arose for discarding one of these general 

 descriptions of the planet's orbit, and framing a different 

 imaginary line, by which to express the series of observed posi- 



