Two Corrections Wittgenstein's Lectures in 1930-33

Two Corrections: Wittgenstein's Lectures in 1930-33 G. E. Moore Mind, New Series, Vol. 64, No. 254. (Apr., 1955), p. 264. Stable URL: http://links.jstor.org/sici?sici=0026-4423%28195504%292%3A64%3A254%3C264%3ATCWLI1%3E2.0.CO%3B2-4 Mind is currently published by Oxford University Press.

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http://www.jstor.org Fri May 18 09:01:36 2007

TWO CORRECTIONS I t has been pointed out to me that I made a great mistake on page 5 of my third article on Wittgenstein'sLecturesin 1930-33(MIND, Jan. 1955), in speaking of " Tarski's 3-valued Logic ", since the calculus in question was invented solely by Professor J. Lukasiewicz, and Tarski had no hand whatever in its invention. I did not know this at the time, and I think I must have been misled into my mistake by Wittgenstein himself, since, on looking up my notes of the passage in question, I find no name mentioned except Tarski's, which is mentioned three times. Of course I cannot be certain that Wittgenstein did not also mention Lukasiewicz : he certainly did a t one point speak of " they ", as if Tarski was not the only person involved : but I think he must a t least have supposed that Tarski was partly responsible for the calculus, even if he did not suppose him to be its sole author. I am now informed, on unimpeachable evidence, that Tarski had no hand whatever in the invention. Lukasiewicz invented the calculus and published an account of it in 1920, before he was even acquainted with Tarski. On looking a t my notes, to find what (so far as they can be trusted) Wittgenstein had said on this first matter, I found that I had badly misrepresented him on another. I represent him as saying that Tarski had called the third value in the calculus " doubt. ful ". But this is a complete mistake. What he actually said was that Tarski had chosen a particular letter to represent the third value, because he supposed this value to '' correspond " to " possible ", and that it did not in fact so correspond. He said nothing whatever about " doubtful ", but only about " possible ". The substitution of "doubtful " for "possible " seems to have been a piece of great carelessness on my part. G. E. MOORE '

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