OTHER MINDS 335 



Formerly, these inconsistent idealists, while tacitly admitting the 

 existence of other people, denied that of matter, for which 

 "Berkeley placed God] Kant and after him Schopenhauer placed 

 Will\ and Clifford placed Mind-Stuff"^ Now, to crown all, Pro- 

 fessor Karl Pearson, pinning his faith to Hume, and declaring that 

 he knows nothing beyond the veil of his sense-impressions, is 

 highly contemptuous of the opinions of these metaphysicians 

 and so joins their company. Even Hume wrote for other minds. 2 



1 Pearson, Grammar of Science, ed. 1900, p. 68, footnote. 



* In this question of other minds lies the crux of the whole problem. When 

 I declare that the only existence known to me is the stream of feelings which 

 constitutes my own mind, and that this stream, especially when I divest it of the 

 coherence conferred by common sense, does not furnish evidence of the existence 

 of anything outside of it, I am on safe ground. But when I suppose that there 

 are other minds, I make a guess which I cannot test, and which is therefore of the 

 same nature as that made by the materialist. Attempts have been made by 

 idealists, who deny or doubt the existence of material objects, to demonstrate 

 the existence of the other minds to which they appeal. For example, J. S. 

 Mill (Examination of Sir William Hamilton's Philosophy, 3rd ed.), declares, " I do 

 not believe that the real externality to us of anything, except other minds, is 

 capable of proof " (p. 239). He distinguishes between actual sensations and 

 Permanent Possibilities of Sensations. The latter are those groups of sensations 

 which we drape, or under fitting conditions might drape, about supposed external 

 objects ; and which, so grouped, may recur again and again. Calcutta is such a 

 Permanent Possibility. " I do believe," says Mill, " that Calcutta exists, though 

 I do not perceive it, and that it would still exist if every percipient inhabitant 

 were suddenly to leave the place, or be struck dead. But when I analyse the 

 belief, all I find in it is, that were these events to take place, the Permanent Possi- 

 bility of Sensation which I call Calcutta would still remain ; that if I were suddenly 

 transported to the banks of the Hoogly, I should still have the sensations, which, 

 if now present, would lead me to affirm that Calcutta exists here and now. We 

 may infer, therefore, that both philosophers and the world at large, when they 

 think of matter, conceive it really as a Permanent Possibility of Sensation. But 

 the majority of philosophers fancy that it is something more ; and the world at 

 large, though they have really, as I conceive, nothing in their minds but a Per- 

 manent Possibility of Sensation, would, if asked the question, undoubtedly agree 

 with the philosophers " (p. 235). In spite, then, of the circumstance that these 

 Permanent Possibilities may exist before the percipient mind, and survive after it, 

 Mill rejects, as unprovable, the notion that they are caused by matter by that 

 which is not part of the mind, but external to it, and which possesses properties 

 that excite in the mind sensations which symbolize those properties. Neverthe- 

 less, because a certain Permanent Possibility (the recurring group of sensations 

 which he calls his body) is constantly associated with his mind, he endows this part 

 of his mind with all his mind ; at any rate, because other of his Permanent Possi- 

 bilities (which he calls the bodies of other people) resemble his body, he supposes 

 that these Possibilities have minds of their own. In other words, he supposes 

 that Possibilities which are not external to his mind have themselves minds which 

 are external to it. From groups of his sensations he thinks he can legitimately 

 infer the existence of other minds ; but, though he believes that other minds can 

 have identical sensations only when placed under identical conditions (e.g. at 

 Calcutta), he thinks he is not in a position to infer the existence of an external 



