216 HUME x 



that relation is nothing but an order of succession, 

 which, so far as our experience goes, is invariable; 

 and it is obvious that the nature of phenomena 

 has nothing to do with their order. Whatever it 

 is that leads us to seek for a cause for every event, 

 in the case of the phenomena of the external 

 world, compels us, with equal cogency, to seek it in 

 that of the mind. 



The only meaning of the law of causation, in 

 the physical world, is, that it generalises universal 

 experience of the order of that world; and, if ex- 

 perience shows a similar order to obtain among 

 states of consciousness, the law of causation will 

 properly express that order. 



That such an order exists, however, is acknowl- 

 edged by every sane man: 



" Our idea, therefore, of necessity and causation, arises 

 entirely from the uniformity observable in the operations 

 of nature, where similar objects are constantly conjoined 

 together, and the mind is determined by custom to infer 

 the one from the appearance of the other. These two 

 circumstances form the whole of that necessity which we 

 ascribe to matter. Beyond the constant conjunction of 

 similar objects and the consequent inference from one to 

 the other, we have no notion of any necessity of con- 

 nexion. 



" If it appear, therefore, what all mankind have ever 

 allowed, without any doubt or hesitation, that these two 

 circumstances take place in the voluntary actions of men, 

 and in the operations of mind, it must follow that all man- 

 kind have ever agreed in the doctrine of necessity, and that 

 they have hitherto disputed merely from not understanding 

 each other." (IV. p. 97.) 



