10 



can be made, in which the ideas are essentially dependent upon 

 one another. Since they are separate to begin with, and are 

 put together to make the complex, whatever differences we 

 can distinguish in a complex idea may be separated into these 

 original elements. And this, in the last analysis, means that 

 there is nothing of the nature of a logical relation between the 

 constituents of our experience. The only thing which deter- 

 mines whether the relations are relatively fixed or not, is the 

 frequency with which the conjunction of ideas has been 

 experienced. 



This theory of the nature of ideas is at the basis of the 

 British associational psychology. Apart from it, association 

 could never have become what it did as a principle of explan- 

 ation of thinking and reasoning. And, with this theory of 

 ideas, it should be quite obvious that no other theory of thought 

 could possibly be held. This word of anticipation should 

 make the understanding of our outline exposition of the 

 Association School entirely free from difficulty. 



3. BERKELEY. 



Berkeley's contribution to the theory of thinking 1 is con- 

 nected with two points: first, his reduction of the law of causa- 

 tion to a principle which holds between the will and ideas, but 

 which cannot possibly hold between ideas, and anything but 

 the will ; second, what may be regarded either as a logical devel- 

 opment of this view of causation, or the logical foundation for 

 it, namely, that between ideas, nothing but customary conjunc- 

 tion can rule, and consequently the laws of nature can only be 

 such conjunctions which we expect will persist, but regarding 

 which we have no certainty. 



4. DAVID HUME. 



Hume, 2 however, sees the basis of Berkeley's development, 

 as already suggested, in the fact that ideas, being simple, and 

 not dependent upon one another in their constitution, must be 

 separable where they are distinguishable, and hence that all 

 thinking consists of such successions of ideas under the guid- 

 ance of the natural relations of contiguity in time or place, 

 resemblance, and cause and effect. 



l ln particular in "Treatise Concerning the Principles of Human Know- 

 ledge", 1710. 



2 In both the "Treatise on Human Nature" and "An Enquiry Concerning 

 Human Understanding", 1738-1748. 



