SENSATION. 79 



iaculties ; it only 1ms to do with tlie question whether such 

 and such a faculty occurs in such and such an organism. 

 Therefore, so long as the question is one of classifying 

 psychical faculties, we can only say that wherever there is 

 -Feeling there is Sensation, and wherever there is no Feeling 

 there is no Sensation.* But where the question is one of 

 classifying organisms witli reference to their psychical facul- 

 ties, it is clear that the difficulty of determining whether or 

 not this and that particular low form of life has the begin- 

 nings of Sensation, is one and the same as the question 

 whether it has the beginnings of Consciousness. Now we 

 have already considered this question, and we have found it 

 impossible to answer; w^e cannot say within broad limits 

 where in the animal kingdom consciousness may first be re- 

 garded as present. But for the sake of drawing the line 

 somew^here with reference to Sensation, I draw it at the place 

 in the zoological scale where we first meet with organs of 

 special sense, that is to say, at the Ccelenterata. In doing 

 this, it is needless to observe, I am drawing the line quite 

 arbitrarily. On the one hand, for anything tliat is known to 

 the contrary, not only the sensitive plant which responds to 

 a mechanical stimulus, but even tlie protoplasmic organisms 

 which respond to a luminous stimulus by congregating in or 

 avoiding the light, may, while executing their responses, be 

 dimly conscious of feeling ; and, on the other hand, the mere 

 presence of an organ of special sense" is certainly no evidence 

 that its activities are accompanied by Sensation. What we 

 call an organ of special sense, is an organ adapted to respond 

 to a special form of stimulation ; but wdiether or not the pro- 

 cess of response is accompanied by a sensation is quite 

 another matter. We infer by a strong analogy that it is so 

 accompanied in the case of organisms like our own (whether 

 of men or of the higher animals) ; but the vaHdity of such 

 inference clearly diminishes wdth the diminishing strength of 

 the analogy — i.e., as we recede in the zoological and psycho- 

 logical scales from organisms like our own towards organisms 

 less and less like. 



Having thus made it as clear as I can that it is only for 

 the matter of convenience that I have supposed the rise of 

 Sensation to coincide with the rise of organs of special 



* Although this sounds like a truism, it is in direct opposition to the 

 classification of LewcF, alluded to above. 



