Wednesday, November 28, 2007

6.1265 One can always conceive of logic in such a way that every proposition is its own proof.

Propositions of logic are rules that say that propositions of that form, i.e. their own form, are legitimate or correct. So they are self-validating. Or so we can understand them.

White (p. 108): “We may consider 6.1265 to be half truth. If it only means that a truth of logic contains within itself all the information necessary to settle its truth value, without using an idea of its derivability from other propositions as a criterion of its being a truth of logic, that can be allowed to stand. If, however, as is natural, we take ‘proof’ to be an epistemological concept, implying that we can always tell whether or not a proposition is logically true by ‘calculating the logical properties of the symbol’ (6.126), we now know that to be false.”

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