DISCRIMINATION AND COMPARISON. ^^l 



see that tlie difference does consist simply in the fact that 

 one object is the same as the other plus something else, or 

 that they both have an identical part, to which each adds 

 a distinct remainder. Thus two pictures may be struck 

 from the same block, but one of them may differ in having 

 color added ; or two carj)ets may show an identical pattern 

 which in each is woven in distinct hues. Similarly, two 

 classes of sensation may have the same emotional tone but 

 negate each other in remaining respects — a dark color and 

 a deep sound, for example ; or two faces may have the same 

 shape of nose but everything else unlike. The similarity 

 of the same note sounded by instruments of different tim- 

 bre is explained by the coexistence of a fundamental tone 

 common to both, with over-tones in one which the other 

 lacks. Dipping my hand into water and anon into a colder 

 water, I may then observe certain additional feelings, broader 

 and deeper irradiations of the cold, so to speak, which were 

 not in the earlier experience, though for aught I can tell, 

 the feelings may be otherwise the same. ' Hefting ' first 

 one weight, and then another, new feelings may start out 

 in my elbow-joint, wrist, and elsewhere, and make me call 

 the second weight the heavier of the twain. In all these 

 cases each of the differing things may be represented by 

 two parts, one that is common to it and the others, and an- 

 other that is peculiar to itself. If they form a series, 

 A, B, C, D, etc., and the common part be called X, whilst 

 the lowest difference be called d, then the composition 

 of the series would be as follows : 



A = X-^d; 



B = (X+ d) + d, oYX-\-2d ; 



C=X-}-3d; 



B = X-]-^d; 



If X itself were ultimately composed of d's we should 

 have the entire series explained as due to the varying com- 

 bination and re-combination with itself of an unvarying ele- 

 ment ; and all the apparent differences of quality would \>e 

 translated into differences of quantity alone. This is the 

 sort of reduction which the atomic theory in physics and 



