SENSATION AND PERCEPTION 115 



But in much of our experience as living organisms the stimula- 

 tion of receptor organs is not followed by any such changes of 

 consciousness. Thus when one is in a state of deep sleep a 

 multitude of receptors are still being stimulated (atmospheric 

 vibrations, for instance, still affect the auditory organs), but 

 there is no consciousness. In ordinary, aimless waking activity 

 there is no doubt that a vast amount of receptor stimulation is 

 not consciously experienced. And in the performance of some 

 learned, automatically effected, muscular task there may be no 

 consciousness of the great variety of stimulations of the visual 

 and tactile receptors, quite apart from the still more complex 

 and numerous stimulations of the proprio-ceptors in the muscles 

 and joints, 



43. ON SENSATION AS A POSSIBLE PHYSICAL 



PROCESS 



Thus we have to consider what is meant by the sensation that 

 may attend the stimulation of a receptor. We discover that 

 sensation by introspection and, strictly speaking, it is only allow- 

 able to me so to discover, or idealize it. But it is really a pretence 

 to take such a (*' solipsistic ") attitude on the part of anyone 

 who speaks or writes about it, since he expects that other men 

 and women will listen to him or read what he writes. Living 

 in community with other human persons we must believe that 

 they also have sensations similar or analogous with those that 

 we discover by introspection. And living also in community 

 with some animals, such as dogs, cats and horses, we must also 

 extend to them the same having of sensations. In spite of all 

 that we read in books of philosophy the denial of this conclusion 

 must be regarded as intellectually dishonest. 



43a. The Train of Events in a Conscious Process. An 

 organic process, in general, is thought about, first, not otherwise 

 than an inanimate one and we always try to symbolize it by a 

 mathematical equation. For instance, the distance, Z), run by 

 a motor-bicycle on a gallon of petrol is a function of several 

 variables ; a, b, c, etc., that is, D = f (a, b, c, etc.) where a, b, c^ 

 etc., are the calorific value of the fuel, the gradients of the roads, 

 the surfaces of the roads, etc. So also the work {W), done by 

 a man, in riding a push-bike, is a function of the foodstuffs 

 (proteins, fats and carbohydrates eaten), that is, W = f {p, f, c). 



