“Tautology leaves to reality the whole infinite logical space; contradiction fills the whole logical space and leaves no point to reality. Neither of them, therefore, can in any way determine reality.
4.464 OGD [→GER | →P/M] The truth of tautology is certain, of propositions possible, of contradiction impossible.
(Certain, possible, impossible: here we have an indication of that gradation which we need in the theory of probability.)
4.465 OGD [→GER | →P/M] The logical product of a tautology and a proposition says the same as the proposition.”