CONTEMPORARY PHILOSOPHY. 17 



us the result of irritating nervous tissue, is just as un- 

 accountable as the appearance of the Djin when Aladdin 

 rubbed his lamp in the story." This is what Mr. Huxley 

 says ; so that he for one, at all events, finds himself at 

 a loss for a middle term when the physical and the 

 metaphysical meet. Whatever be the structure of the 

 ear, it is, in ultimate instance, still a vibration on the 

 physical side that suddenly starts up a sound on the 

 metaphysical side. And in that situation, and as so 

 described, we may best understand what Brown's decision 

 comes to the decision of simple invariableness. What 

 is meant by an abstract A B is perfectly visible there. 

 Vibration is the A, and sound is the B. The vibration 

 is abstract, isolated, on its side ; and the sound is 

 abstract, isolated, on the other side. The relation itself 

 is abstract. The terms of it, the sides of it, only touch : 

 there is no concrete connection between them. Nor is 

 the case easier, or in any way different, where any other 

 meeting place of physiology on the one hand, and 

 psychology on the other, are concerned. Alum and 

 astringency for taste, a rose-leaf and fragrance for smell, 

 wool and warmth for touch : there, too, in each case 

 we have only abstract sides ; the middle term that is 

 concretely to bridge them, we cannot see in any one of 

 them. With sight the difficulty is only greater, and 

 perhaps only all the more that on the one side, the 

 physical one, the intermediation of middle terms is so 

 abundant and curious. To obtain that image on the 

 retina the contrivances are as nice as numerous, as 

 minute as vast ; but the image physiological and the 

 image psychological ditt'er still by the whole diameter of 

 being. Image and image are but an abstract A B. So 

 it will always be when internality and externality are 

 brought into relation. There, too, there is a direct side 

 bv side where the line between has neither breadth nor 



