148 HUME vi 



Next, the foundation of the method of difference 

 is stated : 



" The difference in the effects of two resembling objects must 

 proceed from that particular in which they differ. For, as like 

 causes always produce like effects, when in any instance we find 

 our expectation to be disappointed, we must conclude that this 

 irregularity proceeds from some difference in the causes. "- 

 (I. p. 230.) 



In the succeeding paragraph the method of con- 

 comitant variations is foreshadowed. 



" When any object increases or diminishes with the increase 

 or diminution of the cause, 'tis to be regarded as a compounded 

 effect, derived from the union of the several different effects 

 which arise from the several different parts of the cause. The 

 absence or presence of one part of the cause is here supposed to 

 be always attended with the absence or presence of a proportion- 

 able part of the effect. This constant conjunction sufficiently 

 proves that the one part is the cause of the other. . We must, 

 however, beware not to draw such a conclusion from a few 

 experiments." (I. p. 230.) 



Lastly, the following rule, though awkwardly 

 stated, contains a suggestion of the method of 

 residues : 



". . . an object which exists for any time in its full perfec- 

 tion without any effect, is not the sole cause of that effect, but 

 requires to be assisted by some other principle, which may for- 

 ward its influence and operation. For as like effects necessarily 

 follow from like causes, and in a contiguous time and place, 

 their separation for a moment shows that these causes are not 

 complete ones." (I. p. 230.) 



In addition to the bare notion of necessary con- 

 nexion between the cause and its effect, we un- 



