THE DEVELOPMENT OF CLASSIFICATION 99 



while our discussion of principles in its essence is logical, in another 

 respect it is a merely historical account. The question is not what 

 principles of classification are to be acknowledged as valuable now 

 that the work of the Congress lies behind us, but what principles were 

 accepted and really led to the organization of the work in that form in 

 which it presents itself in the records of the following volumes. 



II 



THE CLASSIFICATION OF THE SCIENCES 



1. The Development of Classification 



The problem of dividing and subdividing the whole of human know- 

 ledge and of thus bringing order into the manifoldness of scientific 

 efforts has fascinated the leading thinkers of all ages. It may often be 

 difficult to say how far the new principles of classification themselves 

 open the way for new scientific progress and how far the great forward 

 movements of thought in the special sciences have in turn influenced 

 the principles of classification. In any case every productive age has 

 demanded the expression of its deepest energy in a new ordering of 

 human science. The history of these efforts leads from Plato and 

 Aristotle to Bacon and Locke, to Bentham and Ampere, to Kant and 

 Hegel, to Comte and Spencer, to Wundt and Windelband. And yet 

 we can hardly speak of a real historical continuity. In a certain way 

 every period took up the problem anew, and the new aspects resulted 

 not only from the development of the sciences themselves which were 

 to be classified, but still more from the differences of logical interest. 

 Sometimes the classification referred to the material, sometimes to 

 the method of treatment, sometimes to the mental energies involved, 

 and sometimes to the ends to be reached. The reference to the mental 

 faculties was certainly the earliest method of bringing order into 

 human knowledge, for the distinction of the Platonic philosophy be- 

 tween dialectics, physics, and ethics pointed to the threefold charac- 

 ter of the mind, to reason, perception, and desire; and it was on the 

 threshold of the modern time, again, when Bacon divided the intel- 

 lectual globe into three large parts according to three fundamental 

 psychical faculties : memory, imagination, and reason. The memory 

 gives us history; the imagination, poetry; the reason, philosophy, 

 or the sciences. History was further divided into natural and civil 

 history; natural history into normal, abnormal, and artificial phe- 

 nomena; civil history into political, literary, and ecclesiastical history. 

 The field of reason was subdivided into man, nature, and God; the 

 domain of man gives, first, civil philosophy, parted off into inter- 



