1 64 DOGMATISM AND EVOLUTION 



give rise to a weakened impulse, yet the feature in question may 

 well enough be entirely disconnected with the peculiar experience, 

 and the incipient differentiation of A that thus arises may count 

 for nothing in the ultimate result. Speaking generally, then, we 

 may say that the effect of an unsuccessful B is to weaken the 

 impulse to B whenever A occurs. Now in numbers of cases the 

 weakened impulse is immediately reinforced by success ; in others 

 it is further sapped by failure; and the two effects may for some 

 time cancel each other without other manifest issue than the 

 heightening of attention. 



What is necessary for the learning-process is a reorganization 

 of the sense-experience A in the two classes of cases; not that 

 new elements should be brought to consciousness, but that the 

 old should be given a new emphasis, so that feeling and active 

 response may attach to the really important marks. The trial- 

 and-error is not simply a selection between movements, but a 

 selection between candidates for the focus. In the latter aspect, 

 as in the former, we have no reason to suppose anything more 

 recondite than a process of summation. A comparatively ob 

 scure feature, which when responded to by B is repeatedly and 

 without exception succeeded by unpleasant after effects, and 

 when responded to by the modified B as invariably leads to 

 pleasant after effects, must finally make its way to the center of 

 attention; while the various false cues, leading to conflicting 

 results, retire into the background. 



Now where the recognition of A (for example) is attended 

 with distinct effort and even when this is no longer generally 

 the case it may still occasionally happen this recognition is its 

 discrimination from a possible A&quot; , as the movements of hesitation 

 suffice to indicate. Thus A and A&quot; sustain a quasi-logical rela 

 tion to each other, as well as to the vaguer image A -or- A 1 of 

 which they are alternative fillings-in. The significance of each 

 is partly that it is not the other. The first impression may be, 

 for example, of a moving something to be attacked or to be 

 avoided; and the aroused attention then amplifies the image so 



