168 PSYCHOLOGY. 



may conspire with the other tones thereof to arouse in my 

 brain the process which suggests to my consciousness his 

 name. And yet I may be ignorant of the overtone per se, 

 and unable, even when he speaks, to tell whether it be there 

 <u' no. It leads me to the idea of the name ; but it pro- 

 duces in me no such cerebral process as that to which the 

 idea of the overtone would correspond. And similarly of our 

 learning. Each subject we learn leaves behind it a modifi- 

 cation of the brain, which makes it impossible for the latter 

 to react upon things just as it did before ; and the result ol 

 the dift'erence may be a tendency to act, though with no idea, 

 much as we should {/" we were consciously thinking about 

 the subject. The becoming conscious of the latter at will 

 is equally readily explained as a result of the brain-modifi- 

 cation. This, as Wundt phrases it, is a ' predisposition ' to 

 bring forth the conscious idea of the original subject, a pre- 

 disposition which other stimuli and brain-processes may 

 convert into an actual result. But such a predisposition is 

 no 'unconscious idea;' it is only a particular collocation of 

 the molecules in certain tracts of the brain. 



Eighth Proof. Instincts, as pursuits of ends by aj)pro- 

 priate means, are manifestations of intelligence ; but as the 

 ends are not foreseen, the intelligence must be unconscious. 



Reply. Chapter XXIV will show that all the phenomena 

 of instinct are explicable as actions of the nervous system, 

 mechanically discharged by stimuli to the senses. 



Ninth Proof. In sense-perception we have results in 

 abundance, which can only be explained as conclusions 

 drawn by a process of unconscious inference from data 

 given to sense. A small human image on the retina is 

 referred, not to a pygmy, but to a distant man of normal 

 size. A certain gray patch is inferred to be a white object 

 seen in a dim light. Often the inference leads us astray : 

 e.g., pale gray against pale green looks red, because we 

 take a wrong premise to argue from. We think a green 

 film is spread over everything ; and knowing that under 

 such a film a red thing would look gray, we wrongly infer 

 from the gray appearance that a red thing must be there. 

 Our study of space-perception in Chapter XVIII will give 

 abundant additional examples both of the truthful andillu* 



