Wittgenstein and Turing on contradictions in mathematics
I believe Wittgenstein thinks that a system in which there are contradictions can still be meaningful and even helpful in certain cases as inconsistency robustness has proved itself. I have selected the following passages from on online source that elucidates how allowing contradictions makes sense in our daily life. It is as if we impose on ourselves some limitations.
Inconsistency robustness is information system performance in the face of continually pervasive inconsistencies---a shift from the previously dominant paradigms of inconsistency denial and inconsistency elimination attempting to sweep them under the rug.
Inconsistency robustness differs from previous paradigms based on belief revision, probability, and uncertainty as follows:
Belief revision: Large information systems are continually, pervasively inconsistent and there is no way to revise them to attain consistency.
Probability and fuzzy logic: In large information systems, there are typically several ways to calculate probability. Often the result is that the probability is both close to 0% and close to 100%
Uncertainty: Resolving uncertainty to determine truth is not a realistic goal in large information systems.
Besides this is Wittgenstein's take on it,
Exactly. "Natural" there is not a mathematical term. It is not mathematically determined what is the natural thing to do. We most naturally compare a contradiction to something which jams. I would say that anything which we give and conceive to be an explanation of why a contradiction does not work is always just another way of saying that we do not want it to work. If you have a tube and a cock which shuts or opens it, your experience may have led you to think that always when the handle is parallel to the tube, the tube is open, and when it is at right angles to it, the tube is closed. But at home I have a cock which works the other way about. And in order to get used to it, I had to think of the handle as lying along the tube and blocking it, so that the tube was closed when the handle was parallel to it. I had to invent a new imagery. Similarly, one needs to change one's imagery in the case of contradictions. One can change one's imagery in such a way that 'p and not-p 'sounds entirely natural, as when we say, "The negative doesn't add anything".
This is most important. We shall constantly get into positions where it is necessary to have a new imagery which will make an absurd thing sound entirely natural. I want to talk about the sense in which we should say that the law of contradiction: - (p. - p) is a true proposition. Should we say that if '-(p. -p)' is a true proposition, it is true in a different sense of the word from the sense in which it is a true proposition that the earth goes round the sun? In logic one deals with tautologies-propositions like '- (p. -p)'. But one might just as well deal with contradictions instead. So that Principia mathematica would not be a collection of tautologies but a collection of contradictions. Should one then say that the contradictions were true? Or would one then say that "true" is being used in a different sense?