CONTENT AND VALIDITY OF THE CAUSAL LAW 359 



There is no controversy regarding the inner similarity of both 

 these types of inference or regarding their outward structure; or, 

 again, regarding their outward difference from the deductive in- 

 ferences, which proceed not from a particular to a particular or 

 general, but from a general to a particular. 



There is, however, difference of opinion regarding their inner 

 structure and their inner relation to the deductive inferences. Both 

 questions depend upon the decision regarding the meaning and 

 validity of the causal relation. The contending parties are recruited 

 essentially from the positions of traditional empiricism and ration- 

 alism and from their modern offshoots. 



We maintain first of all : 



1. The presupposition of all inductive inferences, from now on 

 to be taken in their more general sense, is, that the contents of 

 perception are given to us uniformly in repeated perceptions, that is, 

 in uniform components and uniform relations. 



2. The condition of the validity of the inductive inferences lies 

 in the thoughts that the same causes will be present in the unobserved 

 realities as in the observed ones, and that these same causes will bring 

 forth the same effects. 



3. The conclusions of all inductive inferences have, logically 

 speaking, purely problematic validity, that is, their contradictory 

 opposite remains equally thinkable. They are, accurately expressed, 

 merely hypotheses, whose validity needs verification through future 

 experience. 



The first-mentioned presupposition of inductive inference must not 

 be misunderstood. The paradox that nothing really repeats itself, 

 that each stage in nature's process comes but once, is just as much 

 and just as little justified as the assertion, everything has already 

 existed. It does not deny the fact that we can discriminate in the 

 contents of our perceptions the uniformities of their components 

 and relations, in short, that similar elements are present in these 

 ever new complexes. This fact makes it possible that our manifold 

 perceptions combine to make up one continuous experience. Even 

 our paradox presupposes that the different contents of our percep- 

 tions are comparable with one another, and reveal accordingly 

 some sort of common nature. All this is not only a matter of course 

 for empiricism, which founds the whole constitution of our know- 

 ledge upon habits, but must also be granted by every rationalistic 

 interpretation of the structure of knowledge. Every one that is 

 well informed knows that what we ordinarily refer to as facts already 

 includes a theory regarding them. Kant judges in this matter pre- 

 cisely as Hume did before him and Stuart Mill after him. "If cin- 

 nabar were sometimes red and sometimes black, sometimes light and 

 sometimes heavy, if a man could be changed now into this, now into 



