THE METAPHYSICS OF SENSATION 275 



may be divided into two groups : the primary 

 feelings, which exist in themselves and without 

 relation to any other, such as pleasure and pain, 

 desire, and the simple sensations obtained through 

 the sensory organs ; and the secondary feelings, 

 which express those relations of primary feelings 

 which are perceived by the mind ; and the exist- 

 ence of which, therefore, implies the pre-existence 

 of at least two of the primary feelings. Such are 

 likeness and unlikeness in quality, quantity, or 

 form ; succession and contemporaneity ; contiguity 

 and distance ; cause and effect ; motion and rest. 



Now it is quite true that there is no likeness 

 between the primary feelings which are grouped 

 under sight and touch ; but it appears to me 

 wholly untrue, and indeed absurd, to affirm that 

 there is no likeness between the secondary feelings 

 which express the relations of the primary ones. 



The relation of succession perceived between 

 the visible taps of a hammer, is, to my mind, 

 exactly like the relation of succession between the 

 tangible taps; the unlikeness between red and 

 blue is a mental phenomenon of the same order 

 as the unlikeness between rough and smooth. 

 Two points visibly distant are so, because one or 

 more units of visible length (minima visibilia) are 

 interposed between them ; and as two points 

 tangibly distant are so, because one or more units 

 of tangible length (minima tangibilia) are inter- 

 posed between them, it is clear that the notion of 



T2 



