The Evidence of Mind 33 



which, like the attuning of the violin wood or the slow de- 

 velopment of a muscle, have no conscious accompaniment. 

 We must then ask the question : What kind of learning 

 by experience never, so far as we know, occurs unconsciously ? 

 Suppose a human being shut up in a room from which he can 

 escape only by working a combination lock. As we shall see 

 later, this is one of the methods by which the learning power 

 of animals has been tested. The man, after prolonged 

 investigation, hits upon the right combination and gets out. 

 Suppose that he later finds himself again in the same pre- 

 dicament, and that without hesitation or fumbling he opens 

 the lock at once, and performs the feat again and again, to 

 show that it was not a lucky accident. But one interpretation 

 of such behavior is possible. We know from our own ex- 

 perience that the man could not have worked the lock the 

 second time he saw it, unless he consciously remembered the 

 movements he made the first time ; that is, unless he had in 

 mind some kind of idea as a guide. Here, at least, there can 

 have been no change in the structure of the muscles, for such 

 changes are gradual; the change must have taken place in 

 the most easily alterable portion of the organism, the nervous 

 system; and further, it must have taken place in the most 

 unstable and variable part of the nervous system, the higher 

 cortical centres whose activity is accompanied by conscious- 

 ness. In other words, we may be practically assured that 

 consciousness accompanies learning only when the learning 

 is so rapid as to show that the effects of previous experience 

 are recalled in the guise of an idea or mental image of some 

 sort. But does even the most rapid learning possible assure 

 us of the presence of an idea in the mind of a lower animal ? 

 Where the motive, the beneficial or harmful consequence of 

 action, is very strong, may not a single experience suffice to 

 modify action without being revived in idea? Moreover, 



