130 



HABIT AND INTELLIGENCE. 



[chap. 



It may be 

 extra- 

 mental, or 

 only extra- 

 organic. 



No organ 

 of sense 

 can 



perceive 

 itself. 



by speaking, instead, of the extra-mental world, which 

 includes the body, and of the extra-organic world, which 

 does not include the body.^ But I think the question re- 

 presents a real though a soluble difficulty. If I am right 

 in agreeing with those who think that perception is an 

 inference, we may define the internal world as consisting 

 of aU that is known by direct consciousness ; and tlie 

 external world, as including all that is known only by 

 inference therefrom. In so far as the body is the seat of 

 sensations, it is part of the internal world : in so far as it is 

 an object of perception, it is a part of the external world. 

 It is here to be observed, that when one of our organs of 

 sense becomes an object of perception, it is perceived, not 

 by itself, but by another organ of sense.^ Sight and touch 

 are the only organs by which we perceive objects, because 

 they are the only organs of sense that give any idea of 

 space. The eye cannot see itself, but the hand can feel it ; 

 one hand, or at least one finger, cannot feel itself, but the 

 other hand can feel it, and the eye can see both the hands. 

 Had we but one sense, and were the organ of that one 

 sense incapable of becoming an object of perception to 

 itself, and consequently incapable of becoming an object of 

 perception at all, it would not occur to us to regard it as a 

 part of the external world. 



1 " I have endeavoured to show that the difficulties connected with the 

 apparent deception of the senses can be removed by attending to three 

 distinctions : — 1. That between our original and ac(iuired percejitions : 

 2. That between sensation and perception : 3. That between the objects 

 intuitively perceived : all of them being extra-mental, but some of them 

 also extra-organic." (M'Cosh's Examination of Mill's Philosophy, p. 171, 

 note.) " Objects intuitively perceived which are not extra-organic," must, 

 I suppose, be states of the organism, such as dryness of the throat. 



^ This remark has been made by Professor Ferrier. 



