28 THE SCIENCE OF LOGIC. 



ultimate grounds of our judgments, therefore, the Principle of 

 Sufficient Reason carries us beyond the subjective connexions 

 of thought with thought, and into the reality itself which our 

 thoughts have for object. It is more than formal, more than a 

 law of thought : it is material or real, a law of being, of reality. 



17. REAL, MATERIAL, CRITICAL LOGIC: CRITERIOLOGY, 

 EPISTEMOLOGY, THEORY OF KNOWLEDGE. Finally, to recur 

 to the point mentioned above (10): if we were to concern 

 ourselves in logic merely with the consistency of thought, we 

 should assign to some branch or other of philosophical inquiry 

 the whole question of the validity of thought in the larger sense 

 of its truth. Beyond all questions of the inner dependence of 

 thought on thought in our reasoning processes there is the 

 question of the relation of thought to things. If we assent to each 

 step in a reasoning process because of the previous step, why do 

 we assent to the first step? If the formal canons of inference 

 guarantee the truth of a conclusion not absolutely but only hypo- 

 thetically, i.e. on the assumption that the premisses are true, what 

 guarantee have we for the truth of the latter? What are the tests 

 or criteria of the truth of our knowledge, and which of them is 

 fundamental? What, in ultimate analysis, are the motives of our 

 certitude about truths which we consider to be evident? Can we, 

 on reflection, find adequate reasonable grounds for our spontaneous 

 assents and beliefs? Or does a critical examination of our in 

 tellectual assents lead to universal doubt and scepticism ? What 

 is the nature of the &quot; evidence &quot; to which we appeal in justification 

 of our beliefs and convictions ? What is the nature of the mental 

 act of judgment and what precisely is it that constitutes the truth 

 we claim for it? Do the abstract and universal concepts which 

 we use as predicates, and often as subjects, in our judgments, 

 represent anything given to us in the data of our sense experience? 

 And are these sense phenomena themselves exclusively mental 

 creations pure products of sense consciousness or do they re 

 present an extramental reality? Can an analysis of our processes 

 of sense perception and of the origin and growth of intellectual 

 knowledge throw any light upon the validity of the latter? Are 

 there any rules or canons to guide us in the methods by which we 

 are to observe the phenomena of mind and matter, to form our 

 general concepts about things, to classify things, to acquire uni 

 versal or scientific knowledge about things, and to prove \ establish, 

 justify, this knowledge ? 



