102 ROYCE— PRINCIPLES OF THEORETICAL SCIENCE [April 19, 



such as come to mind when we assert, deny, infer, or otherwise 

 deal with the relations expressed by the words '' and," " or," '' not," 

 *' implies " and a few similar terms. But these forms of relations 

 are themselves the forms in which our will embodies itself. So that 

 our theories of the universe tend to be like the other works of our 

 civilization, the result of a long struggle with nature, by means of 

 which, when we win at all, we attain the end of finding our own will 

 expressed in the order of the controllable facts. Some such con- 

 sideration the modern study of the principles of theoretical science 

 seems to me to enforce ; and from this point of view I regard this 

 study as belonging to what Franklin had in mind when he used 

 the term '' useful knowledge." 

 Cambridge, Mass., 

 April 18, 1906. 



