Mental Processes in Man. 309 



hearing, the stippling, if we may so extend the use of this 

 term, is also very fine, as is shown by the fact that 

 musicians can, according to Weber, distinguish notes 

 separated in the scale of sounds by only one-sixtieth part 

 of a musical tone. In touch the stippling is comparatively 

 coarse. But in all cases there is a stippling; and yet 

 from these stippled sensations the mind in all cases elabo- 

 rates a continuum. The visual image is continuous, not- 

 withstanding the retinal stippling and the existence of the 

 blind spot. When we lay our hands on a smooth table we 

 fill in the interstices between the sensational points, and 

 feel the surface as continuous. In all cases out of the 

 stippled sense-stimuli we form a continuum. 



The next thing that we have to note is that it is not so 

 much the sensation itself, as that which gives origin to 

 it, that we habitually refer outwards to the recipient end 

 of the afferent fibre. In referring a sensation of touch to 

 a certain part of the skin, it is of something touching us 

 that we seem to be immediately conscious. We refer the 

 stimulus to an object in the external world, which we 

 localize, and which we believe to have given rise to the 

 sensation. 



This, however, is more clearly seen in the case of 

 vision. When we look through the window and see an 

 object such as a house before us, we do not habitually 

 localize the sensation in a certain part of the retina, but 

 we refer the object to a particular position more or less 

 distant in the world around us. This projection of the 

 object outwards in a right line from the e\es is really a 

 marvellous process, though the wonder of it is lost in its 

 familiarity. It is the outcome of the experience of hundreds 

 of generations. And the experience is not gained through 

 vision alone, but through this in combination with other 

 senses and activities. We see an object, but we have to 

 go to it before we can touch it. It is not in contact with 

 us, but distant from us. Its outness and distance is a 

 matter of what is termed the geometry of the senses ; and 

 this geometry has been elaborated through many genera- 



