OF BODY AND SPACE. 163 



modification of the organic system in sight or hearing and the dependent sensation, there will 

 be no greater difficulty in supposing the first apprehension of body (independent as yet of any 

 reference to the notions of Form or Magnitude) to take place antecedent to all objective 

 knowledge of the hand, than there is in supposing a sensation of sight or of hearing ante- 

 cedent to the earliest knowledge of the eye or the ear. 



The relation between body and space may be illustrated by comparison with the case of 

 light and darkness ; the second of the two correlatives in both instances belonging to the class 

 called by Locke positive ideas from negative causes. It is certain that a man born blind can 

 have as little knowledge of black or darkness as he has of colour or of light ; but as soon as 

 his eye has once been opened to the visible world he will be able to look in a direction from 

 whence no light reaches the eye, or even to try to see in the total absence of all light, when the 

 effect of the effort will be to direct his attention to a phenomenon, which, under the name of 

 black or darkness, will constitute as positive an object of thought as that which arises from the 

 actual impact of light upon the retina. 



In like manner it is generally admitted that the infant antecedent to the first apprehension 

 of body is as ignorant of the space which surrounds him, as the born-blind is of darkness. But 

 as soon as the infant has once apprehended body, without as yet having any thought of his own 

 corporeal frame, he will be able (like the blind man, who after recovering his sight, tries to 

 see in the absence of light) to seek with the muscular organ after the phenomenon with which 

 he has newly become acquainted ; that is, to feel for body in a direction in which there is none 

 within his reach, when of course he will move his hand freely through space. The question is, 

 what effect will such an action produce on the knowledge of the agent? Under what aspect 

 can such an action be contemplated in the mind of a being who has no thought of himself and 

 no conception of a bodily instrument in muscular exertion ? It cannot be supposed that the 

 infant in stretching out his hand in the search after body will be sensible of none of those fun- 

 damental impressions by which, if the action were ours, we should appreciate the extent of the 

 exertion. He cannot be wholly unconscious of an effort not induced by mere organic excite- 

 ment but aimed at an object of distinct thought, viz. the body represented to his imagination. 

 It seems to me that the case is precisely analogous to that of the born-blind who is trying to 

 see when first replaced in darkness after the recovery of vision ; and as, in the latter case the 

 attempt to exercise the visual faculty has the effect of directing the attention of the sentient 

 being to the darkness which meets his efforts, and thereby becomes manifest to his intelligence ; 

 so it appears to me the attempt to apprehend body with the organ of external touch will direct 

 the attention of the infant to the space traversed by his hand, as a positive phenomenon, 

 exhibiting an elementary kind of being, the idea of which will thus be acquired in the same 

 empirical manner by the exercise of the same faculties with the idea of Body. 



When once we have learned to consider Space as the object revealed by muscular effort in 

 the absence of Body, the resistance of a rigid body to the pressure of our hand will be felt as the 

 action of the bodily substance opposing our effort and preventing us from obtaining experience 

 of space lying beyond the resisting surface, and pervading the solid substance underneath. 



In process of time circumstances will arise which will lead us to pass our hand over the 

 surface of bodies in a lateral direction, when the absence of resistance to muscular exertion 



21—2 



