364 THE SENSORIAL FUNCTIONS. 



ter, is to extend the meaning of the term matter to that with 

 which we cannot perceive it has any relation. All that we 

 know of matter has regard to space: nothing that we know 

 of the properties and affections of mind has any relation 

 whatsoever to space. 



A similar incongruity is contained In the proposition that 

 thought is :{ function of the hrain. It is not the brain which 

 thinks, any more than it is the eye which sees, though each 

 of these material organs is necessary for the production of 

 these respective effects. That which sees and which thinks 

 is exclusively the mind; although it is by the instrumentali- 

 ty of its bodily organs that these changes take place. At- 

 tention to this fundamental distinction, which, although ob- 

 vious when explicitly pointed out, is often lost sight of in 

 ordinary discourse, will furnish a key to the solution of 

 many questions relating to perception, which have been 

 considered as difficult and embarrassing. 



The sensations derived from the different senses have no 

 resemblance to one another, and have, indeed, no property 

 in common, except that they are felt by the same percipient 

 being:. A colour has no sort of resemblance to a sound; nor 

 have either of these any similarity to an odour, or a taste, 

 or to the sensations of heat, or cold. But the mind, which 

 receives these incongruous elements, has the power of 

 giving them, as it were, cohesion, of comparing them with 

 one another, of uniting them into combinations, and of form- 

 ing them into ideas of external objects. All that nature 

 presents is an infinite number of particles, scattered in diffe- 

 rent parts of space; but out of these the mind forms indivi- 

 dual groups, to which she gives a unity of her own crea- 

 tion. 



All our notions of material bodies involve that of space; 

 and we derive this fundamental idea from the peculiar sensa- 

 tions which attend the actions of our voluntary muscles. 

 These actions first give us the idea of our own bodies, of its 

 various parts, and of their figure and movements; and next 

 teach us the position, distances, magnitudes, and figures of 



