274 PSYCHOLOGY. 



great chasm between sensation and perception by showing how raw the 

 material is out of which the fair structure is upreared. Only two senses 

 serve objective perception : touch and sight. They alone furnish the 

 data on the basis whereof the Understanding, by the process indicated, 

 erects the objective world. . . . These data in themselves are still no 

 perception ; that is the Understanding's work. If I press with my hand 

 against the table, the sensation I receive has no analogy with the idea 

 of the firm cohesion of the parts of this mass : only when my Under- 

 standing passes fi'om the sensation to its cause does it create for itself 

 a body with the properties of solidity, impenetrability, and hardness. 

 When in the dark I lay my hand on a surface, or grasp a ball of three 

 inches diameter, in either case the same parts of the hand receive the 

 impression : but out of the different contraction of the hand in the two 

 cases my Understanding constructs the form of the body whose contact 

 caused the feeling, and confirms its construction by leading me to move 

 my hand over the body. If one born blind handles a cubical body, the 

 sensations of his hand are quite uniform on all sides and in all direc- 

 tions,— only the corners press upon a smaller part of his skin. In these 

 sensations, as such, there is nothing whatever analogous to a cube. But 

 from the felt resistance his Understanding infers immediately and 

 intuitively a cause thereof, which now presents itself as a solid body; 

 and from the movements of exploration which the arms made whilst 

 the feelings of the hands remained constant he constructs, in the space 

 known to him a priori, the body's cubical shape. Did he not bring 

 with him ready-made the idea of a cause and of a space, with the laws 

 thereof, there never could arise, out of those successive feelings in his 

 hand, 1,he image of a cube. If we let a string run through our closed 

 hand, we immediately construct as the cause of the friction and its dura- 

 tion in such an attitude of the hand, a long cylindrical body moving 

 uniformly in one direction. But never out of the pure sensation in the 

 hand could the idea ot movement, that is, of change of position in space 

 by means of time, arise : such a content can never lie in sensation, nor 

 come out of it. Our Intellect, antecedently to all experience, must bear 

 in itself the intuitions of Space and Time, and therewithal of the possi- 

 bility of motion, and no less the idea of Causality, to pass from the 

 empirically given feeling to its cause, and to construct the latter as a 

 so moving body of the designated shape. For how great is the abyss 

 between the mere sensation in the hand and the ideas of causality, 

 materiality, and movement through Space, occurring in Time! The 

 feeling in the hand, even with different contacts and positions, is some- 

 thing far too uniform and poor in content for it to be possible to con- 

 struct out of it the idea of Space with its three dimensions, of the 

 action of bodies on each other, with the properties of extension, impen- 

 etrability, cohesion, shape, hardness, softness, rest, and motion — in 

 short, the foundations of the objective world. This is only possible 

 through Space, Time, and Causality . . . being preformed in the 

 Intellect itself, . . . from whence it again follows that the peraeption 



