Mental actions dtie to complex causes. 103 



The principle of causation forms the basis of many 

 minor ones, such as selection, evolution, differentia- 

 tion, &c. Plurality of causes also is a very common 

 circumstance in all the sciences, and especially in 

 concrete phenomena, and in the complex ones of 

 animal life ; the arrival of a ship for example at a 

 distant port, is a result of many conditions. Similarly 

 with most of our mental actions, they are compounds- 

 of feeling and intellect, and produced by many causes, 

 such as hereditary tendency, acquired habit, internal 

 and external mental excitants, dogmatic belief, know- 

 ledge of empirical rules, and occasionally of verified 

 principles. Several of these causes also frequently 

 conspire to produce a single idea or decision. 



Various general principles of lesser magnitude arise 

 from the combined action of two or more of the 

 greater ones, and these also appear to operate in 

 mental actions as well as in physical ones. Thus by 

 the combined influence of causation and of the prin- 

 ciple that every phenomenon occupies time, "effects 

 often lag behind their causes ; " and in some cases- 

 during a long period. The greatest heat of summer 

 for example usually occurs several weeks after mid- 

 summer. The mental effects of early mistakes are 

 often not fully experienced until old age. The de- 

 cline of a nation also follows a long time behind the 

 period of action of the chief causes which produce it. 



Although effects are indissolubly connected with 

 their causes, they frequently do not occur in an active 

 form until a long period after them. In such cases 



