THE STREAM OF THOUGHT. 231 



And the view of these philosophers has been called little 

 into question, for our common experience seems at first 

 sight to corroborate it entirely. Are not the sensations we 

 get from the same object, for example, always the same ? 

 Does not the same piano-key, struck with the same force, 

 make us hear in the same way ? Does not the same grass 

 give us the same feeling of green, the same sky the same 

 feeling of blue, and do we not get the same olfactory sen- 

 sation no matter how many times we put our nose to the 

 same flask of cologne ? It seems a piece of metaphysical 

 sophistry to suggest that we do not; and yet a close at- 

 tention to the matter shows that there is no 'proof that the 

 same bodily sensation is ever got hy us twice. 



What is got twice is the same object. We hear the same 

 note over and over again ; we see the same quality of green, 

 or smell the same objective perfume, or experience the same 

 species of pain. The realities, concrete and abstract, i^hysi- 

 cal and ideal, whose permanent existence we believe in, 

 seem to be constantly coming ujd again before our thought, 

 and lead us, in our carelessness, to suppose that our 'ideas ' 

 of them are tlie same ideas. When we come, some time 

 later, to the chapter on Perception, we shall see how invet- 

 erate is our habit of not attending to sensations as subjec- 

 tive facts, but of simply using them as stejDping-stones to 

 pass over to the recognition of the realities Avhose presence 

 they reveal. The grass out of the window now looks to me 

 of the same green in the sun as in the shade, and yet a 

 painter would have to paint one part of it dark brown, 

 arother part bright yellow, to give its real sensational effect. 

 We take no heed, as a rule, of the different way in which 

 the same things look and sound and smell at different dis- 

 tances and under different circumstances. The sameness 

 of the things is what we are concerned to ascertain ; and 

 any sensations that assure us of that will probably be con- 

 sidered in a rough way to be the same with each other. 

 This is what makes off-hand testimony about the subjective 

 identity of different sensations well-nigh worthless as a 

 proof of the fact. The entire history of Sensation is a com- 

 mentary on our inability to tell whether two sensations 

 received apart are exactlv alike. What appeals to our 



