ADVANTAGES OF EXPLANATORY TREATMENT 105 



tions are more interesting and more easily remembered than empirical 

 descriptions. This is perfectly true, but it is not the whole or the chief 

 truth. Let it here be understood that the duty of a geographer is two- 

 sided; he must first gain a correct knowledge and he must then give an 

 intelligible description of the facts of his subject; and it can not be 

 doubted for a moment by any geographer who has carefully tried to fulfill 

 both sides of his duty that both the investigation and the investigator are 

 greatly aided by the adoption of an explanatory method. I believe this to 

 be true in all branches of geography, and particularly in the study of land 

 forms. Hence the strongest reason for advancing from the older-fashioned 

 empirical treatment to the newer-fashioned explanatory treatment lies in 

 the greater power of the newer treatment, in the power of deeper penetra- 

 tion on the part of the investigator into the real nature of the facts con- 

 cerned, and, more particularly in relation to our present discussion, in the 

 power of clearer and more intelligible presentation of the described land- 

 scape to the properly qualified reader. The ground for this statement, 

 which is here still made with special reference to land forms, but which 

 is I believe equally true for all divisions of geography, organic and inor- 

 ganic, may be more fully appreciated by considering what follows. 



ADVANTAGES OF EXPLANATORY TREATMENT 



Whenever an explorer desires to describe the features of the landscape 

 that he traverses, he must necessarily describe them in terms of previously 

 acquired mental concepts, and these mental concepts may be called his 

 mental geographical equipment ; furthermore, after an explorer has writ- 

 ten and printed a report on his explorations, his descriptions can be 

 properly understood only by those readers who are in possession of essen- 

 tially the same kind of mental geographical equipment as the one that the 

 explorer possessed. Now, there are in use today two unlike kinds of 

 mental geographical equipments for the descriptions of land forms — one 

 made up of empirical concepts, independent of all theory, the other of 

 explanatory concepts, which are absolutely dependent on theory. Em- 

 pirical concepts must be learned by heart, for they are not reasonably 

 connected by an understanding of the origin of the forms that they repre- 

 sent ; they are simply matters of observational experience arbitrarily com- 

 bined, too often after the fashion of these fanciful artistic compositions, 

 picturing imaginary landscapes, which one used to see on an early page of 

 geographical text books, and in which mountains and tablelands, water- 

 falls, and deltas were so marvelously juxtaposed. Explanatory concepts 

 are, on the contrary, reasonably associated with one another and with the 

 general principles from which they are derived, so that they are easily 

 remembered in spite of their great variety, 



