218 INDUCTION. 



observation elicited fresh facts contradictory to these representations, other 

 epicycles and other eccentrics 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 colhgation ; they all enabled the mind to represent to itself with facility, 

 and by a simultaneous glance, the whole body of facts at the time ascer- 

 tained : 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 afterward arose for discarding one of these gene'ral descriptions 

 of the planet's orbit, and framing a different imaginary line, by which to 

 express tlie series of observed positions, it was because a number of new 

 facts liad now been added, which it was necessary to combine with the old 

 facts into one general description. But this did not affect the correctness 

 of the former expression, considered as a general statement of the only facts 

 which it was intended to represent. And so true is this, that, as is well re- 

 marked by M. Comte, these ancient generalizations, even the rudest and 

 most imperfect of them, that of uniform movement in a circle, are so far 

 from being entirely false, that they are even now habitually employed by 

 astronomers when only a rough approximation to correctness is required. 

 "L'astronomie moderne, en detruisant sans retour les hypotheses primi- 

 tives, envisagees comme lois reelles du monde, a soigneusement maintenu 

 leur valeur positive et permanente, la propriete de representer commode- 

 ment les phenomenes quaiid il s'agit d'une premiere ebauche. Nos res- 

 sources a cet egard sont meme bien plus etendues, precisement a cause 

 que nous ne nous faisons aucune illusion sur la realite des hypotheses ; ce 

 qui nous perniet d'employer sans scrupule, en chaque cas, celle que nous 

 jugeons la pins avantageuse."* 



Dr. Whewell's remark, therefore, is philosophically correct. Successive 

 expressions for the colligation of observed facts, or, in other words, succes- 

 sive descriptions of a phenomenon as a whole, which has been observed 

 only in parts, may, though conflicting, be all correct as far as they go. But 

 it would surely be absurd to assert this of conflicting inductions. 



The scientific study of facts may be undertaken for three different jsur- 

 poses: the simple description of the facts; their explanation; or their pre- 

 diction : meaning by prediction, the determination of the conditions under 

 which similar facts may be expected again to occur. To the first of these 

 three operations the name of Induction does not properly belong : to the 

 )ther two it does. Now, Dr. Whewell's observation is true of the first 

 alone. Considered as a mere description, the circular theory of the heaven- 

 ly motions represents perfectly well their general features : and by adding 

 epicycles without limit, those motions, even as now known to us, might be 

 expressed with any degree of accuracy that might be required. The ellip- 

 tical theory, as a mere description, would have a gi-eat advantage in point 

 of simplicity, and in the consequent facility of conceiving it and reasoning 

 about it ; but it would not really be more true than the other. Different 

 descriptions, therefore, may be all true : but not, surely, different explana- 

 tions. The doctrine that the heavenly bodies moved by a virtue inherent 



* Cours de Philosophie Positive, vol. ii., p. 202. 



