94 



SCIENCE. 



[Vol. XV. No. 366 



several agencies, which enter into the combined result in vary- 

 ing proportions. The true explanation is therefore necessarily 

 complex. Such complex explanations of phenomena are specially 

 encouraged by the method of multiple hypotheses, and consti- 

 tute one of its chief merits. We are so prone to attribute a 

 phenomenon to a single cause, that, when we find an agency 

 present, we are liable to rest satisfied therewith, and fail to 

 recognize that it is but one factor, and perchance a minor factor, 

 in the accomplishment of the total result. Take for illustra- 

 tion the mooted question of the origin of the Great Lake basins. 

 "We have this, that, and the other hypothesis urged by different 

 students as the cause of these great excavations; and all of these 

 are urged with force and with fact, urged justly to a certain 

 degree. It is practically demonstrable that these basins were 

 river-valleys antecedent to the glacial incursion, and that they 

 owe their origin in part to the pre-existence of those valleys and 

 to the blocking- up of their outlets. And so this view of their 

 origin is m-ged with a certain truthfulness. So, again, it is 

 demonstrable that they were occupied by great lobes of ice, 

 ■which excavated them to a marked degree, and therefore the 

 theory of glacial excavation finds support in fact. I think it is 

 furthermore demonstrable that the earth's crust beneath these 

 basins was flexed downward, and that they owe a part of their 

 origin to crust deformation. But to my judgment neither the 

 one nor the other, nor the third, constitutes an adequate 

 explanation of the phenomena. All these must be taken 

 together, and possibly they must be supplemented by other 

 agencies. . The problem, therefore, is the determination not 

 only of the participation, but of the measure and the extent, of 

 each of these agencies in the production of the complex result. 

 This is not likely to be accomplished by one whose working 

 hypothesis is pre-glacial erosion, or glacial erosion, or crust 

 deformation, but by one whose staff of working hypotheses 

 embraces all of these and any other agency which can be 

 rationally conceived to have taken part in the phenomena. 



A special merit of the method is, that by its very nature it 

 promotes thoroughness. The value of a working hypothesis lies 

 largely in its suggestiveness of lines of inquiry that might 

 otherwise be overlooked. Facts that are trivial in themselves 

 are brought into significance by their bearings upon the .hy- 

 pothesis, and by their causal indications. As an illustration, it 

 is only necessary to cite the phenomenal influence which the 

 Darwinian hypothesis has exerted upon the investigations of 

 the past two decades. But a single working hypothesis may 

 lead investigation along a given line to the neglect of others 

 equally important; and thus, while inquiry is promoted in 

 certain quarters, the investigation lacks in completeness. But 

 if all rational hypotheses relating to a subject are worked 

 co-equally, thoroughness is the presumptive result, in the very 

 nature of the case. 



In the use of the multiple method, the re-action of one hy- 

 pothesis upon another tends to amplify the recognized scope of 

 each, and their mutual conflicts whet the discriminative edge 

 of each. The analytic process, the development and demonstra- 

 tion of criteria, and the sharpening of discrimination, receive 

 powerful impulse from the co-ordinate working of several 

 hypotheses. 



Fertility in processes is also the natural outcome of the 

 method. Each hypothesis suggests its own criteria, its own 

 means of proof, its own methods of developing the truth ; and 

 if a group of hypotheses encompass the subject on all sides, the 

 total outcome of means and of methods is full and rich. 



The use of the method leads to certain peculiar habits of 

 mind which deserve passing notice, since as a factor of educa- 

 tion its disciijlinary value is one of importance. "When faith- 

 fully pursued for a period of years, it develops a habit of 

 thought analogous to the method itself, which may be desig- 

 nated a habit of parallel or complex thought. Instead of a 

 simple succession of thoughts in linear order, the procedure 

 is complex, and the mind appears to become possessed of 

 the power of simultaneous vision from different standpoints. 

 Phenomena appear to become capable of being viewed analyti- 

 cally and synthetically at once. It is not altogether unlike the 



study of a landscape, from which there comes into the mind 

 myriads of lines of intelligence, which are received and 

 co-ordinated simultaneously, producing a complex impressioo 

 which is recorded and studied directly in its complexity. My 

 description of this process is confessedly inadequate, and the 

 affirmation of it as a fact would doubtless challenge dispute at 

 the hands of psychologists of the old school; but I address 

 myself to naturalists who I think can respond to its verity from 

 their own experience. 



The method has, however, its disadvantages. No good thing 

 is without its drawbacks; and this very habit of mind, while 

 an invaluable acquisition for purposes of investigation, intro- 

 duces difficulties in expression. It is obvious, upon considera- 

 tion, that this method of thought is impossible of verbal 

 expression. "We cannot put into words more than a single line 

 of thought at the same time; and even in that the order of 

 expression must be conformed to the idiosyncrasies of the 

 language, and the rate must be relatively slow. "Wheii the 

 habit of complex thought is not highly developed, there is 

 usually a leading line to which others are subordinate, and the 

 difficulty of expression does not rise to serious proportions; but 

 when the method of simultaneous vision along different lines is 

 developed so that the thoughts running in different channels are 

 nearly equivalent, there is an obvious embarrassment in selec- 

 tion and a disinclination to make the attempt. Furthermore, 

 the impossibility of expressing the mental operation in words 

 leads to their disuse in the silent processes of thought, and 

 hence words and thoughts lose that close association which 

 they are accustomed to maintain wit;h those whose silent as 

 well as spoken thoughts run in linear verbal courses. There i 

 therefore a certain predisposition on the part of the practitioner 

 of this method to taciturnity. 



"We encounter an analogous diflSiculty in the use of the 

 method with young students. It is far easier, and I think in 

 general more interesting, for them to argue a theory or accept 

 a simple interpretation than to recognize and evaluate the 

 several factors which the true elucidation may require. To 

 illustrate: it is more to their taste to be taught that the Great 

 Lake basins were scooped out by glaciers than to be urged to 

 conceive of three or more great agencies working successively 

 or simultaneously, and to estimate how much was accomplished 

 by each of these agencies. The complex and the quantitative 

 do not fascinate the young student as they do the veteran 

 investigator. 



It has not been our custom to think of the method of work- 

 ing hypotheses as applicable to instruction or to the practical 

 affairs of life. "We have usually regarded it as but a method 

 of science. But I believe its application to practical affairs has 

 a value co-ordinate with the importance of the affairs them- 

 selves. I refer especially to those inquiries and inspections 

 that precede the coming-out of an enterprise rather than to its 

 actual execution. The methods that are superior in scientific 

 investigation should likewise be superior in those investigations 

 that are the necessary antecedents to an intelligent conduct of 

 affairs. But I can dwell only briefly on this phase of the 

 subject. 



In education, as in investigation, it has been much the prac- 

 tice to work a theory. The search for instructional methods 

 has often proceeded on the presumption that there is a definite 

 patent process through which all students might be put and 

 come out with results of maximum excellence : and hence 

 pedagogical inquiry in the past has very, largely concerned 

 itself with the inquiry, "What is the best method?" rather 

 than with the inqiry, ""What are the special values of different 

 methods, and what are their several advantageous applica- 

 bilities in the varied work of instruction?" The past doctrine 

 has been largely the doctrine of pedagogical uniformitarianism. 

 But the faculties and functions of the mind are almost, if not 

 quita, as varied as the properties and functions of matter; and it 

 is perhaps not less absurd to assume that any specific method 

 of instructional procedure is more effective than all others, 

 under any and all circumstances, than to asume that one prin- 

 ciple of interpretation is equally applicable to all the phenomena 



