40 THE SCIENCE OF LOGIC 



(3) And C does not vary concomitantly with h, 

 While /&quot;does vary concomitantly with h t 

 Therefore/ is not C ; 



and so on, until all the &quot;forms&quot; except one, say Z, are thus 

 eliminated by syllogisms in Cesare or Camestres. Then we have, 

 finally, this mixed disjunctive argument in the modus tollendo 

 ponens, verifying the form of heat as Z : 



/&quot;is either A or B or C or . . . X or Y or Z ; 

 But/is neither A nor B nor ... X nor Y ; 

 Therefore /&quot;is Z. 



This latter form of argument is regarded by many as the 

 typically &quot; inductive &quot; inference. 1 The various arguments, (i), (2), 

 and (3), by which we apply various methods of elimination, sug 

 gest that instances (of the circumstances accompanying heat) are 

 no longer being merely enumerated, but that the nature of their 

 connexion (with heat) is being sifted by experiment. This marks 

 the transition from enumerative to scientific induction. 



As was pointed out already, two possible tendencies may 

 arise from an incomplete enumeration of instances. The first, 

 with which many of the Scholastics, and Bacon himself, seem to 

 have been preoccupied, is to realize, somehow or other, the ideal 

 of a complete enumeration. To realize it actually is, for the most 

 part, chimerical, and moreover, it does not lead us to the true 

 universal. To realize it virtually, i.e. by falling back on some 

 rational principle which might justify us in saying : &quot; and so on of 

 the unexamined instances &quot; &quot; et sic de ceteris &quot; is to yield in 

 reality to the second tendency, while under the traditional sway 

 of the first : the second tendency being to abandon the mere 

 enumeration of the instances, to concentrate attention on their 

 material side, on the quality, the nature of the facts we are 

 dealing with, and to ask ourselves : Is it not possible and per 

 missible to rise to the conception and enunciation of a strictly 

 universal physical law from an examination of some instances only ? 

 It is possible to do so; and the difficulty of the process of 

 physical induction, by which we accomplish this ascent, is not a 

 difficulty of principle or method, but rather of application : it is a 

 difficulty that belongs not to the logical, but to the practical, 

 order. 2 



The ancient Greek philosophers, and the Scholastics of the 

 Middle Ages, were quite as well aware as any modern exponent 

 1 Cf. 197 ; JOSEPH, op. cit., p. 405. 2 C/. JOYCE, op. cit., p. 217. 



