GENERAL VIEW OF NATURE AND SCOPE OF LOGIC. 29 



Obviously these are all questions of fundamental importance. 

 They have been discussed at all times by philosophers ; but there 

 has always been much difference of opinion and practice as to the 

 proper place for treating them. The earlier scholastic philoso 

 phers usually discussed them immediately after the questions of 

 Formal logic and described them as forming Material or Real or 

 Applied logic, or again as Logica Critica, in opposition to Logica 

 Dialectica, which was the title they gave to the logic of formally 

 valid inference. Modern scholastics are inclined to state and ex 

 pound briefly the practical rules and canons which constitute 

 Method both inductive and deductive in Logic, and to leave the 

 fuller discussion of all the great underlying principles of knowledge 

 to a special treatise which they call Criteriology or Epistemology, 

 or Theory of Knowledge, and which they claim to be a special branch 

 or department of psychology, or of metaphysics, rather than a 

 section of logic. 1 It is quite true that the treatment of many of 

 these questions must be largely psychological and ontological. 

 Nor is it possible or desirable to draw a sharp line of demarcation 

 between these sciences. 



There is a tendency among modern writers on logic to 

 discuss in logic itself all the presuppositions of the science : all 

 the deeper questions about truth, certitude, and knowledge to 

 which an analysis of thought gives rise. But these had better be 

 left as far as possible to some department of metaphysics, which 

 analyses the principles of all the other sciences most appro 

 priately to that special department which investigates the validity 

 of human knowledge and the ultimate grounds for human certi 

 tude. In the present treatise the questions that have an immediate 

 bearing on the truth, as well as those concerning the consistency, 

 of our thoughts, will be brought under notice ; the presuppositions 

 of induction will be dealt with. But the larger questions con 

 cerning the ultimate criteria of truth and the ultimate motives 

 of certitude are left to epistemology. 



WELTON, Logic, i., pp. 1-40. JOYCE, Logic, ch. i. and note. KEYNES, 

 Formal Logic, Introd. and Appendix B. JOSEPH, Logic, ch. i. MERCIER, 

 Criteriologie Generate, Introd. 



1 Cf. MERCIER, Criteriologie Generate, sme edit., Introd., pp. ii. sqq. 



