410 INTRODUCTION TO PHILOSOPHY OF SCIENCE 



employing a form which is essentially that of logical subordi- 

 nation and not obviously one of serial arrangement, the 

 other (Bliss) employing a form which is predominantly 

 ordinal. Though Peirce is motivated by the philosophical 

 or theoretical interest, and Bliss is concerned with the prac- 

 tical desire to construct an adequate classificatory scheme 

 for books, nevertheless Bliss is convinced that such a scheme 

 will be adequate to the extent to which it corresponds closely 

 with the order of nature; hence the problem is similarly con- 

 ceived by both writers. 



PEIRCE 



Peirce's classification is predominantly trichotomic, most 

 of the studies being divisible into three species according 

 to a repeating plan, "the First of the three members relating 

 to universal elements or laws, the Second arranging classes 

 of forms and seeking to bring them under universal laws, 

 the Third going into the utmost detail, describing individual 

 phenomena and endeavoring to explain them." * This type 

 of division can be illustrated by psychical science, which is 

 subdivided into nomological psychics or psychology, classi- 

 ficatory psychics or ethnology, and descriptive psychics 

 or history. "Nomological psychics discovers the general 

 elements and laws of mental phenomena. . . . Classifica- 

 tory psychics classifies the products of mind and endeavors 

 to explain them on psychological principles. . . . Descrip- 

 tive psychics endeavors in the first place to describe indi- 

 vidual manifestations of mind, whether they be permanent 

 works or actions; and to that task it joins that of endeavor- 

 ing to explain them on the principles of psychology and 

 ethnology." 2 



All studies are either sciences of discovery, sciences of 

 review, or practical sciences. Elsewhere 3 he groups the 

 first two under the general heading, theoretical science. The 

 science of discovery consists of mathematics, philosophy, 

 and idioscopy (the special sciences). The subdivisions of 



1 Collected Works, Vol. I, par. 1.180. 2 Ibid., par. 1.189. 3 Ibid., par. 1.239. 



