302 The Theory of Gcfietic Modes 



of the uniformity and lawfulness of experience. But we 

 saw on an earlier page that it is not necessary that the 

 categories, which are themselves the outcome of regular 

 experience, should apply only to phenomena which them- 

 selves illustrate that regularity. There are certain cate- 

 gories of thinking and of objective interpretation whose 

 content is the changing, the genetic, the in-a-sense-capri- 

 cious, yet which themselves stand for and represent in 

 mental growth the uniformity and lawfulness of experi- 

 ence. So it becomes necessary to distinguish between 

 those types of experience which illustrate a mental rule 

 or category on the one hand, and those which produce it 

 on the other hand. It may be quite true that one can- 

 not think of a change as taking place in nature without 

 asking for the changes which preceded it; this is the 

 requirement that the category of change finds in phe- 

 nomena its justification ; but it is quite a different thing to 

 say that the antecedent change which this category of 

 thought postulates is a sufificient statement of that which 

 follows, and that for which a scientific account is sought. 

 There are categories, therefore, whose application requires 

 change or variation even in the midst of the regularities 

 by which they themselves are produced.^ This it is 

 which characterizes the ' genetic ' categories.^ 



§ 2. The First Postulate of the Theoiy of Ge7ietic Modes 



So important is this consideration for a criticism of 

 science, that the failure to recognize it constitutes a 



1 The category of change, indeed, is constituted by the regularity of change. 



2 The phrase ' dynamic categories ' is sometimes used (see Ormond, The 

 Foundations of Knowledge, Part II., Chap. VIIL), but with a meaning not in 

 all respects coincident with that here given to the term ' genetic' 



