4 PSYCHOLOGY. 



of discourse, with their relations not brought out. The first 

 time we see light, in Condillac's phrase we are it rather 

 rather than see it. But all our later optical knowledge is 

 about what this experience gives. And though we were 

 struck blind from that first moment, our scholarship in the 

 subject would lack no essential feature so long as our mem- 

 ory remained. In training-institutions for the blind they 

 teach the pupils as much about light as in ordinary schools 

 E-efiectiou, refraction, the spectrum, the ether-theory, etc., 

 are all studied. But the best taught born-blind pupil of 

 such an establishment yet lacks a knowledge which the 

 least instructed seeing baby has. They can never show him 

 what light is in its ' first intention ' ; and the loss of that 

 sensible knowledge no book-learning can replace. All this 

 is so obvious that we usually find sensation ' j)ostulated ' 

 as an element of experience, even by those philosophers who 

 are least inclined to make much of its importance, or to 

 pay respect to the knowledge which it brings.* 



* " The sensations which we postulate as tlie signs or occasions of our 

 perceptions" (A. Seth: Scottish Philosophy, p. 89). " Tlieir existence is 

 supposed only because, "without them, it would be impossible to account 

 for the complex phenomena which are directly present in consciousness " 

 (J. Dewey: Psychology, p. 34). Even as great an enemy of Sensation as 

 T. H. Green has to allow it a sort of hypothetical existence under protest. 

 " Perception presupposes feeling " (Conlemp. Review, vol. xxxi. p. 747). 

 Cf . also such passages as those in his Prolegomena to Ethics, §§ 48, 49. — 

 Physiologically, the sensory and the reproductive or associative processes 

 may wa.\ and wane independently of each other. Where the part directly 

 due to stimulation of the sense-organ preponderates, the thought has a 

 sensational character, and differs from other thoughts in the sensational 

 direction. Those thoughts which lie farthest in that direction we call sen- 

 sations, for practical convenience, just as we call conceptions those which 

 lie nearer the opposite extreme. But we no more have conceptions pure 

 than we have pure sensations. Our most rarefied intellectual .states involve 

 some bodily sensibility, just as our dullest feelings have some intellectual 

 scope. Common-sense and common psychology e.vpress this by saying 

 that the mental state is composed of distinct fractional parts, one of which 

 is sensation, the other conception. We. however, who believe ^very 

 mental state to be an integral thing (p. 276) cannot talk thus, but must 

 speak of the degree of sensational or intellectual character, or function, oJ 

 the mental state. Professor Hering puts, as usual, his finger better upon 

 the truth than anyone else. Writing of visual perception, he says: "It 

 is inadmissible in the present state of our knowledge to assert that first 

 and last the same retinal picture arouses exactly the s&vae pure sensation, 



