146 GROVE KARL GILBERT— DAVIS [MEiIol& \vouxxi, 



augment the established groups," and thus enables the observer "to concentrate his attention 

 and sharpen his vision." The inductive or empirical classification thus begun "is a stepping 

 stone to a logical, or rational, or, more strictly, relational classification ... it leads to the 

 understanding of those deeper relations which constitute the order of nature." 



With the progress of observation and classification, the desire then arises to discover the 

 "antecedents" of which the observed facts are the "consequents." Here enters the aid of 

 hypotheses, which as they are invented — usually by an unconscious mental process — must be 

 subjected to tests for the determination of their competence; and here lies " the prime difference 

 between the investigator and the theorist. The one seeks ddigently for the facts which may 

 overturn his tentative theory, the other closes his eyes to these and searches only for those 

 which will sustain it." Is there any reader of this statement who, on scrutinizing his own 

 record, can declare himself always to have been an investigator, as thus denned, and never a 

 theorist ? It is next pointed out that an investigator will find " advantage in entertaining several 

 [hypotheses] at once, for then it is possible to discover their mutual antagonisms and incon- 

 sistencies, and to devise crucial tests . . . untd he finds an hypothesis that remains unscathed 

 after all the tests his imagination can suggest. . . . Evidently, if the investigator is to succeed 

 in the discovery of veritable explanations of phenomena, he must be fertile in the invention of 

 hypotheses and ingenious in the application of tests." 



This declaration introduces a striking passage, already quoted in connection with Gilbert's 

 education at Rochester: "The practical questions for the teacher are, whether it is possible by 

 training to improve the guessing faculty, and if so, how it is to be done." Another soon follows: 

 It is recognized that a majority of students "ask only for a store of knowledge," but the modern 

 educator believes that training the mind is more important than storing it, and he therefore 

 employs "such methods in storing the minds of his pupils with knowledge that they acquire at 

 the same time the best training." It is as a part of training in method that the "guessing 

 faculty" is given so high a rank. If the teacher, imbued with the vastness of science, yields to 

 the temptation of giving his pupil, especially those whose careers are not to be scientific, " a maxi- 

 mum number of facts . . . there is reason to fear that a permanent misconception is established, 

 and the essence of science is not communicated." The teacher "will do better to contract the 

 phenomenal, and enlarge the logical scope of his subject, so as to dwell on the philosophy of 

 the science rather than its material." Young teachers in particular will profit by reviewing their 

 growing experience in the light of this advice. 



THE SCIENTIFIC GUESS 



The "scientific guess as a mental process" is then analyzed. In so far as it embodies a 

 search for an explanatory hypothesis of certain observed facts, it is shown to depend on " analogic 

 suggestions." That is: "Given a phenomenon, A, whose antecedent we seek. First, we ran- 

 sack the memory for some different phenomenon, B, which has one or more features in common 

 with A, and whose antecedent we know. Then we pass by analogy from the antecedent of B to 

 the hypothetical antecedent of A, solving the analogic proportion — as B is to A, so is the ante- 

 cedent of B to the antecedent of A. Having thus obtained an hypothesis, we proceed to test 

 it," as above. But testing hypotheses is given a lower value rank than inventing them. 



The great investigator is primarily and preeminently the man who is rich in hypotheses. In the plenitude 

 of his wealth he can spare the weakling without regret; and having many from which to select, his mind maintains 

 a judicial attitude. The man who can produce but one, cherishes and champions that one as his own, and is 

 blind to its faults. With such men, the testing of alternative hypotheses is accomplished only through contro- 

 versy. Crucial observations are warped by prejudice, and the triumph of the truth is delayed. 



How few can, near the end of their career, read those lines without wishing that, on some 

 occasions at least, they had taken more the attitude of a judge and less that of a champion! 



The investigator who has reached a sound conclusion involving a new principle is then 

 urged to "describe the route by which his end was reached." Let him — 



recite every hypothesis that occurred to him in the course of his search, telling, if he can, how it was suggested. 

 Let him lay bare the considerations which rendered it plausible, the tests that were conceived, and those which 



