144 PHYSIOLOGY. 



honest man, he is made to follow an association that he former- 

 ly made ; and now he remembers the whole of the circumstances, 

 and that it is justly demanded. It is in marking these relations, 

 and judging of them as before, that the whole of our intellectual 

 operations consist. So a man in his senses runs over the asso- 

 ciations, takes up in course the several relations, applies the 

 same judgment as before, and acts in consistency with his usual 

 train ; and this is what is called a man's having common sense. 

 When, upon the contrary, a man does not recollect the relations 

 that he had formerly established, we say that he is out of his 

 senses. Thus also, if a man comes into a company, there are 

 certain observances which custom has established, and his beha- 

 viour is suited according to the company he comes into ; if it is 

 a company of his usual merry companions, presently all their 

 thoughts are of merriment, the laugh arises and the joke goes 

 round ; but if it is a company for business that he is to take a 

 part in, he sits down seriously, speaks of the business in hand, 

 and attends to what the other persons are engaged in ; but if he 

 were to treat the last company as he does the first, he would pass 

 for a madman; thus too in the first company I supposed, he may 

 speak of his amours or of his mistress ; but if he finds the same 

 men among a number of ladies of honour and virtue, and he re- 

 news his discourse there, he would be thought a madman. So it 

 is nothing but pursuing our ordinary train of associations, and 

 marking their relations, and acting with the consistency that 

 belongs to them, that constitutes what is called a sensible 

 man ; and delirium is where we do not follow our ordinary 

 train, but, on the contrary, pursue one inconsistent with all 

 our former established principles or notions. This delirium 

 will accordingly depend upon some fault of memory chiefly ; 

 but this will be more considerable still, if not only the or- 

 dinary train of our associations is disturbed, but at the same 

 time the imagination so far prevails as to obtrude upon the 

 mind ideas which do not belong to the train which we are pur- 

 suing. Erroneous judgment accordingly consists chiefly in 

 disjoining ideas which ought to be joined, or in joining those 

 which ought not to be joined. It may therefore be referred to 

 the heads of incoherence and inco-nsistence with regard to the 

 proper connexion of ideas. But it is to be remarked, that there 



