44 HABIT AND INTELLIGENCE. [chap. 



of pleasure and pain). But when all this has been done, 

 that whole class of facts which are variously called feel- 

 Feeling is ing, sensation, consciousness, and emotion, remains unex- 

 cable^^" plained, and incapable of explanation. We can compare 

 one feeling with another, and to a great extent we are 

 able to ascertain where, when, and how, feelings arise. 

 But it is in the nature of things impossible to teU what a 

 feeling is. A man born blind may be made to understand 

 that the colour of green arises when the eyes are directed 

 to grass or leaves : and this is real knowledge, so far as it 

 goes ; but no possible explanation could make him under- 

 stand what the sensation of green is. To use a mathe- 

 matical mode of speech, sensation and consciousness can- 

 not be described in terms of anything but themselves. 

 Thought is But with thought it is otherwise. Thought — even 

 explicable, ^mconscious thought — is always derived from conscious 

 elements, and may be described in terms of conscious- 

 ness. It is, I believe, universally admitted, that all 

 thought begins with sensation ; but sensation, and the 

 consciousness of sensation, are not themselves thought. 

 It begins The first elementary act of thought is the conscious- 

 ^J^L*^/ ness, not of sensations, but of the relation of sensations 



S61IS6 01 



the rela- to each other ; — the consciousness, for instance, of the 

 sensations Hkeness or unlikeness between two or more sensations, 



to each qj, Qf their co-existence or succession in time, or of 

 other. . . . 



their co-existence or separation in space. Now, when 



there are two or more feelings present to the consciousness 



at once, the consciousness is generally directed to one 



more than to the rest ; or, in common language, the mind 



Attention attends to one rather than to the rest. For instance, if 



particular music and talk are both going on at once, the attention will 



sensation, probably be directed either to the music or to the talk, but 



not to both. This sometimes takes place involuntarily, 



*''' ^°. °?®j, sometimes by a voluntary determination. In such a case 



relation as this, the cousciousness is directed to one sensation, or set 



sen^tions. of scnsations, rather than to the other. But the conscious- 



x , ness is also capable of being directed, not to a particular 



in geo- sensation or set of sensations, but to a particular relation or 



study!^ set of relations between sensations. The best instance of 



