296 ON SENSATION AND THE UNITY OF 



the most probable conclusions which are to be 

 drawn from the latest investigations of physiolo- 

 gists. In order to judge how completely this is 

 the case, it will be well to study some simple case 

 of sensation, and, following the example of Reid 

 and of James Mill, we may begin with the sense 

 of smell. Suppose that I become aware of a 

 musky scent, to which the name of " muskiness " 

 may be given. I call this an odour, and I class it 

 along with the feelings of light, colours, sounds, 

 tastes, and the like, among those phenomena 

 which are known as sensations. To say that I 

 am aware of this phenomenon, or that I have it, 

 or that it exists, are simply different modes of 

 affirming the same facts. If I am asked how I 

 know that it exists, I can only reply that its 

 existence and my knowledge of it are one and the 

 same thing; in short, that my knowledge is im- 

 mediate or intuitive, and, as such, is possessed of 

 the highest conceivable degree of certainty. 



The pure sensation of muskiness is almost sure 

 to be followed by a mental state which is not a 

 sensation, but a belief, that there is somewhere, 

 close at hand, a something on which the existence 

 of the sensation depends. It may be a musk- 

 deer, or a musk-rat, or a musk-plant, or a grain 

 of dry musk, or simply a scented handkerchief; 

 but former experience leads us to believe that the 

 sensation is due to the presence of one or other of 

 these objects, and that it will vanish if the object 



