SENSATION. 7 



one new simple idea [i.e. sensation] in the mind. ... I would have 

 any one try to fancy any taste which had never affected his palate, or 

 frame the idea of a scent he had never smelt ; and when he can do this, 

 I will also conclude that a blind man hath ideas of colors, and a deaf 

 man true distinct notions of sounds." * 



The brain is so made that all currents in it run one way. 

 Consciousness of some sort goes with all the currents, but 

 it is only when new currents are entering that it has the 

 sensational tang. And it is only then that consciousness 

 directly encounters (to use a word of Mr. Bradley's) a real- 

 ity outside itself. 



The difference between such encounter and all concep- 

 tual knowledge is very great. A blind man may know all 

 about the sky's blueness, and I may know all about your 

 toothache, conceptually ; tracing their causes from primeval 

 chaos, and their consequences to the crack of doom. But 

 so long as he has not felt the blueness, nor I the toothache, 

 our knowledge, wide as it is, of these realities, will be hollow 

 and inadequate. Somebody must feel blueness, somebody 

 must have toothache, to make human knowledge of these 

 matters real. Conceptual systems which neither began nor 

 left off in sensations would be like bridges without piers. 

 Systems about fact must plunge themselves into sensation 

 as bridges plunge their piers into the rock. Sensations are 

 the stable rock, the terminus a quo and the terminus ad quern 

 of thought. To find such termini is our aim with all our 

 theories — to conceive first when and where a certain sensa- 

 tion may be had, and then to have it. Finding it stops dis- 

 cussion. Failure to find it kills the false conceit of 

 knowledge. Only when you deduce a possible sensation 

 for me from your theory, and give it to me when and where 

 the theory requires, do I begin to be sure that your thought 

 has anything to do with truth. 



Pure sensations can only he realized in the earliest days of life. 

 They are all but impossible to adults with memories and 

 stores of associations acquired. Prior to all impressions 

 on sense-organs the brain is plunged in deep sleep and con- 

 sciousness is practically non-existent. Even the first weeks 



* Op. cit. bk. II. ch. II. § 2. 



