ON THE THEORY OF SCIENCE 339 



embraces these factors. A question as to the why has here, as with 

 the temporal complexes, no definite meaning. There are countless 

 things that happen together once to which we pay no attention 

 because they happen only once or but seldom. The knowledge 

 of the fact that such a single concurrence exists amounts to nothing, 

 since from the presence of one factor it does not lead to a conclusion 

 as to the presence of another, and therefore does not make possible 

 prediction. Of all the possible, and even actual combinations, only 

 those interest us which are repeated, and this arbitrary but expedient 

 selection produces the impression that the world consists only of 

 combinations that can be repeated ; that, in other words, the law of 

 causality or of the type is a general one. However general or limited 

 application these laws have, is more a question of our skill in finding 

 the constant combinations among those that are present than a ques- 

 tion of objective natural fact. 



Thus we see the development and pursuit of all sciences going on in 

 such a way that on the one hand more and more constant combina- 

 tions are discovered, and on the other hand more inclusive relations 

 of this kind are found out, by means of which elements are united 

 with each other which before no one had even tried to bring together. 

 So sciences are increasing both in the sense of an increasing complica- 

 tion and in an increasing unification. 



If we consider from this standpoint the development and procedure 

 of the various sciences, we find a rational division of the sum total of 

 science in the question as to the scope and multiplicity of the com- 

 binations or groups treated of in them. These two properties are in 

 a certain sense antithetical. The simpler a complex is, that is, the 

 fewer elements brought together in it, the more frequently it is met 

 with, and vice versa. One can therefore arrange all the sciences in 

 such a way that one begins with the least multiplicity and the greatest 

 scope, and ends with the greatest multiplicity and the least scope. 

 The first science will be the most general, and will therefore contain 

 the most general and therefore the most barren concepts; the last 

 will contain the most specific and therefore the richest. 



What are these limiting concepts? The most general is the concept 

 of thing, that is, any piece of experience, seized arbitrarily from the 

 flux of our experiences, which can be repeated. The most specific 

 and richest is the concept of human intercourse. Between the science 

 of things and the science of human intercourse, all the other sciences 

 are found arranged in regular gradation. If one follows out the 

 scheme the following outline results: 



1. Theory of order. "] 



2. Theory of numbers, or arithmetic. I ,, , 



. . > Matnematics. 



3. Theory of time. 



4. Theory of space, or geometry. 



