2i 4 THE SCIENCE OF LOGIC 



But, regarded in their proper, objective sense, as characteristics of the 

 judgment, i.e. of the relation between the mind and its object, logical truth 

 and error imply contradictorily opposite relations of the mind to its object : 

 that of positive conformity with the latter, and that of positive discrepancy or 

 divergence from it. Granted some definite relation or other of the mind to 

 the thing, or, in other words, some judgment about the thing, the opposition 

 between these two kinds of relation is contradictory opposition : the relation 

 is either one of agreement or one of disagreement ; there is no mean. Every 

 judgment has a contradictory ; and of a pair of contradictories one must be 

 true and the other must be false. We cannot have, as a mean between them, 

 a judgment which is partly true and partly false. 



This last statement seems at first sight entirely opposed to our ordinary 

 habits of thought and expression. Are we not constantly describing state 

 ments we hear, as &quot; more or less true,&quot; as containing &quot; a certain amount of 

 truth,&quot; or &quot; a grain of truth and a large measure of error &quot; ? Are we not 

 constantly distinguishing truth from error in the judgments formed and ex 

 pressed in every department of experience ? That is undoubtedly so ; but 

 what, in reality, does it prove ? Merely that such statements are ambiguous, 

 are open to a variety of interpretations, express or imply or suggest not one 

 simple judgment, but many ; and that, while some of these latter are true, 

 some also are erroneous. 



249. THREE KINDS OF CERTITUDE : METAPHYSICAL, PHYSI 

 CAL, AND MORAL. Our assent to any judgment as true may be 

 influenced, and often is, no doubt, largely influenced, by motives 

 of a non-intellectual character, by our likes or dislikes, by our 

 character and beliefs, by our feelings and emotions. Of these 

 logic cannot take account, except indirectly : its main concern is 

 with the intellectual motives , the rational grounds or reasons, of our 

 assents. Assent is an intellectual act, and no assent can be 

 rational without sufficient rational grounds. Moreover, it is our 

 reason that must ultimately decide what weight of influence we 

 may prudently and reasonably allow to non-intellectual motives 

 in determining our assent in any given case. Logic, then, is con 

 cerned with the intellectual grounds of certitude, and these are all 

 included in the term &quot;evidence&quot;. 



Now, broadly speaking, we may distinguish three great sources 

 of evidence, and three corresponding kinds of certitude. 1 (a) 

 Analysis and comparison of abstract ideas involving some judg 

 ments that are immediately evident, and others mediately evident, 

 inferred from the former are processes which yield metaphysical 

 certitude, (b) The testimony of our senses involving judgments 

 about the immediate data of our sense experience, and general 



1 Cf. TOOHEY, The Three kinds of Certitude, in the Irish Theological Quarterly, 

 vol. iv., n. 15, pp. 254 sqq. (July, 1909). 



