he will say, even if I feel pain every time when another body O is hurt, I shall never say, 'I feel O's pain', but always, 'My pain is in O's body'.
We cannot declare this statement of the idealist to be false; it is just a different way of adapting our language to the imagined new circumstances, and the rules of language are, in principle, arbitrary. But, of course, some uses of our words may recommend themselves as practical and well adapted; others may be condemned as misleading. Let us examine the idealist's attitude from this point of view.
He rejects our proposition R and replaces it by the other one:
- 'I can feel pain in other bodies as well as in my own.' (S)
He wants to insist that any pain I feel must be called my pain, no matter where it is felt, and in order to assert this he says:
- 'I can feel only my pain.' (T)
Sentence T is, as far as the words are concerned, the same as Q. I have used slightly different signs by having the words 'can' and 'my' printed in italics, in order to indicate that, when used by the solipsist, these two words have a signification which is different from the signification they had in Q when we interpreted Q as meaning the same as P. In T 'my pain' no longer means 'pain in body M', because, according to the solipsist's explanation, 'my pain' may also be in another body O; so we must ask: what does the pronoun 'my' signify here?
It is easy to see that it does not signify anything; it is a superfluous word which may just as well be omitted. 'I feel pain' and 'I feel my pain' are, according to the solipsist's definition, to have identical meaning; the word 'my' .therefore, has no function in the sentence. If he says, 'The pain which I feel is my pain', he is uttering a mere tautology, because he has declared that whatever the empirical circumstances may be, he will never allow the pronouns 'your' or 'his' to be used in connection with 'I feel pain', but always the pronoun 'my'. This stipulation, being independent of emperical facts, is a logical rule, and if it is followed, T becomes a tautology; the word 'can' in T (together with 'only') does not denote empirical impossibility, but logical impossibility. In other words it would not be false, it would be nonsense (grammatically forbidden) to say T can feel somebody else's pain'. A tautology, being the negation of nonsense, is itself devoid
