308 LOGIC 



is art, which would be a glaring case of /uero/fao-is eis aXXo ycvos. The 

 art-bearings of the science are given in the normative character of its 

 subject-matter. As a science logic is descriptive and explanatory, that 

 is, it describes and formulates the norms of valid thought, although 

 as science it is not normative, save in the sense that the principles 

 formulated in it may be normatively or regulatively applied, in 

 which case they become precepts. What is principle in science 

 becomes precept in application, and it is only when technically 

 applied that principles assume a mandatory character. Validity is not 

 created by logic. Logic merely investigates and states the conditions 

 and criteria of validity, being in this reference a science of evidence. 

 In the very fact, however, that logic is normative in the sense of 

 describing and explaining the norms of correct thinking, its practical 

 or applied character is given. Its principles as known are science; 

 its principles as applied are art. There is, therefore, no reason to 

 sunder these two things or to call logic an art merely or a science 

 merely ; for it is both when regarded from different viewpoints, 

 although one must insist on the fact that the rules for practical 

 guidance are, so far as the science is concerned, quite ab extra. Logic, 

 ethics, and aesthetics are all commonly (and rightly) called norm- 

 ative disciplines: they are all concerned with values and standards; 

 logic with validity and evidence, or values for cognition; ethics 

 with motives and moral quality in conduct, or values for volition; 

 aesthetics with the standards of beauty, or values for appreciation 

 and feeling. Yet none of them is or can be merely normative, or 

 indeed as science normative at all; if that were so, they would not 

 be bodies of organized knowledge, but bodies of rules. They might 

 be well-arranged codes of legislation on conduct, fine art, and evi- 

 dence, but not sciences. Strictly regarded, it is the descriptive and 

 explanatory aspect of logic that constitutes its scientific character, 

 while it is the specific normative aspect that constitutes its logical 

 character. Values, whether ethical or logical, without an examina- 

 tion and formulation of their ground, relations, origin, and intercon- 

 nection, would be merely rules of thumb, popular phrases, or pastoral 

 precepts. The actual methodology of the sciences or applied logic 

 is logic as art. 



II. Relation of logic to psychology. 



The differentiation of logic and psychology in such way as to be 

 of practical value in the discussion of the disciplines has always been 

 a difficult matter. John Stuart Mill was disposed to merge logic in 

 psychology, and Hobhouse, his latest notable apologete, draws no 

 fixed distinction between psychology and logic, merely saying that 

 they have different centres of interest, and that their provinces 



