PSYCHOLOGY 45 



but also for a special theory of knowledge under which the outcome of 

 scientific activity has, to Pearson's satisfaction, been subsumed; logic 

 has become the master. The same logic is, none the less, an indispens- 

 able servant. We may set aside the whole business of making systems : 

 yet we shall never plan an investigation, or carry out a research, or . 

 present our results to our fellow workers, without calling in the aid of 

 logic. Scientific activity and logical activity are always and every- 

 where intermingled; a book like Jevons' "Principles of Science" is, 

 in the nature of the case, very largely a logic ; it is logic that adds the 

 subjunctive and imperative moods to Poincare's scientific indicative. 

 And if, for all these reasons, the clean distinction of the two activities 

 is intrinsically difficult, it becomes the more so in the concrete case, 

 seeing that the specialist in science is likely to employ a special logic, the 

 logic of his special point of view and of the " facts " which that point 

 of view discloses, so that he seems presently to work by " intuition " and 

 the activities appear to have been blended rather than intermixed. 



Still, the activities are in themselves different; and in the main, in 

 the broad, our thinking must recognize their difference. We are, again, 

 not to split hairs, or to attempt any hard and fast distinction. But let 

 the reader take up a text-book — that very practical thing — in some one 

 of the newer sciences ; let him go through it, pencil in hand ; and let him 

 mark, as he reads, the passages that are derived from scientific activity 

 on the writer's part and the passages that are logical. Sometimes, of 

 course, he will be in doubt; and the doubtful passages, since we are 

 making but a rough and ready test, may be left unmarked. They will 

 occur most often in the early chapters of the book, — partly because the 

 introductory chapters are likely to be of a general character, partly be- 

 cause the reader is not yet skilled to distinguish the one sort of writing 

 from the other. As more and more pages are turned, the marking be- 

 comes easier, more prompt and more certain; the reader feels that he 

 has the key to the cryptogram ; and the result is instructive enough to 

 warrant the few hours that have been given to the task. 



IV 



We may sum up these paragraphs in the statement that science is 

 defined by its point of view. The scientific man looks out upon ex- 

 perience from a certain standpoint; sees and can see his world only 

 under one aspect; and by this attitude, which he has taken up toward 

 experience, is limited to a particular type of method and to a particular 

 type of problem. To invite him from his "academic reserve," or to 

 demand that he interest himself in " practical ends," is simply to bid 

 him cease from scientific activity. The scientific man, again, is logical, 

 just as the historian or the jurist is logical ; but logic is not science ; and 

 within science the facts of observation take precedence, and logical 



