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The fecond clafs I defined to be that in which a confideration 

 of the conncEiion of caufes and efteds is diredly or indiredly 

 involved. That where fuch a connedtion is the objed of inquiry- 

 probability only is attainable, is a dire6t inference from what has 

 been mentioned with regard to the third cl.ifs If we are wholly 

 ignorant of the nature of all caufes and their modes of operating, 

 we cannot be in any cafe certain of the connection of effedls with 

 each other, or with thofe caufes to which they are afcribed. 



ATr. Hume has indeed, from this principle, drawn a much more 

 extenfive conclufion. From our ignorance of the nature of the 

 connexion of caufe and effed he has inferred, that we cannot 

 reafon about the exijfence of fuch a connexion ; and that our 

 fuppofition of its exiftence is only the refult of a cuflomary 

 tranfition of the mind from the one objed to the other. This 

 inference, which is the foundation of his fcepticifm, is fupported 

 by the following argument. Between thefe two propofitions 

 / have found that fuch an objeEl has always been attended with fuch 

 an effeB^ and / forefee that other objeds^ which are^ in appearance^ 

 fmilar^ will be attended with fimilar effe&s, the connedion is not 

 intuitive. There is therefore required a medium which may 

 enable the mind to draw fuch an inference, if indeed it be drawn 

 by reafoning and argument. But there is not any fuch medium, 

 fmcc the idea of fuch a connedion cannot be fuggefted by any 

 fmgle inftance, and there is nothing, in a number of inftances, dif- 

 ferent from any fingle inftance which is fuppofed to be exadly 

 fimilar, except only that after a repetition of fimilar inftances the 

 snind is carried by habit, upon the appearance of one event, ta 



exped 



