SECT. 26.] Modality. . 321 



first place the province of this Dialectic was much too wide, 

 for it covered in addition the whole field of what we should 

 now term Scientific or Material Induction. The distinctive 

 characteristic of the dialectic premises was their want of 

 certainty, and of such uncertain premises Probability (as I 

 have frequently insisted) takes account of one class only, 

 Induction concerning itself with another class. Again, not the 

 slightest attempt was made to enter upon the enquiry, How 

 uncertain are the premises ? It is only when this is at 

 tempted that we can be considered to enter upon the field of 

 Probability, and it is because, after a rude fashion, the modals 

 attempted to grapple with this problem, that we have regarded 

 them as in any way occupied with our special subject-matter. 

 26. Amongst the older logics with which I have made 

 any acquaintance, that of Crackanthorpe gives the fullest dis 

 cussion upon this subject. He divides his treatment of the 

 syllogism into two parts, occupied respectively with the de 

 monstrative and the probable syllogism. To the latter a 

 whole book is devoted. In this the nature and consequences 

 of thirteen different loci l are investigated, though it is not 

 very clear in what sense they can every one of them be re 

 garded as being probable. 



tical theory of Probability, but in the the term. Crackanthorpe says of 

 infancy of a science it is of course them, &quot; sed duci a loco probabiliter 

 hard to say whether any particular arguendi, hoc vere proprium est Ar- 

 subject is definitely contemplated or gumentationis probabilis ; et in hoc 

 not. Leibnitz (as Todhunter has a Demonstratione differt, quia De- 

 shown in his history) took the great- monstrator utitur solummodo qua- 

 est interest in such chance problems tuor Locis eisque necessariis.... Prae- 

 as had yet been discussed. ter hos autem, ex quibus quoque 

 1 By loci were understood certain probabiliter arguere licet, sunt multo 

 general classes of premises. They plures Loci arguendi probabiliter; 

 stood, in fact, to the major premise ut a Genere, a Specie, ab Adjuncto, 

 in somewhat the same relation that ab Oppositis, et similia&quot; (Logica, 

 the Category or Predicament did to Lib. v., ch. n.). 



v. 21 



