50 DOGMATISM AND EVOLUTION 



portentously difficult to show how it (as a relation without 

 specific terms) is not a mere abstract idea. So to save the rela- 

 tion as an abstraction Berkeley denies that it is an idea or know- 

 able by means of ideas. 



For Hume, however, who knows nothing of 'notions/ the 

 Lockian classification is inevitable. Relations, like modes and 

 substances, are a class of complex ideas. Just how they are 

 specifically characterized is harder to make out. Hume has often 

 been accused of verbal inconsistency of which, like a true Bacon- 

 ian, he takes little account. But in this case his vacillating modes 

 of expression seem to point to a real unclearness and inconsistency 

 of thought, and ultimately to an untenable postulate underlying 

 his whole treatment. In the first place, complex ideas in general 

 are introduced to consideration as remarkable effects of the asso- 

 ciation of ideas ; and it is said that they "generally arise from some 

 principle of union [i. e., association] among our simple ideas." 1 

 With two of the three classes of complex ideas this appears to 

 be invariably the case. The idea of a substance or of a mode is 

 a "collection of simple ideas that are united by the imagination 

 and have a particular name assigned them," association by con- 

 tiguity and causation being necessary to the first, while (pre- 

 sumably) either this or resemblance is necessary to the second. 

 But a relation may arise "even upon the arbitrary union of two 

 ideas in the fancy," "without a connecting principle." Relations, 

 then, are not complex ideas in the sense of being products of 

 association. What then is a relation? Hume has two answers. 

 First, it is "that particular circumstance in which ... we may 

 think proper to compare" two ideas; or, "any particular subject 

 of comparison." But, secondly, a certain example (which he 

 cites) "will be allowed by philosophers to be a true relation, be- 

 cause we acquire an idea of it by the comparing of objects." Is, 

 then, the relation the basis or the product of the process of com- 

 parison; or how, upon Hume's principles, can it be both? Again, 

 "those qualities, which make objects admit of comparison, and 



^Treatise of Human Nature, Book I, Part I Section 4; italics ours. 



