Contradiction and Inconsistency: Different? But The Same. (+ some thoughts on 3-valued logics)
Sprache des Vortragstitels:
Englisch
Original Tagungtitel:
The Inaugural Symposium on Logic in the Arab World
Sprache des Tagungstitel:
Englisch
Original Kurzfassung:
In various philosophical fields people usually distinguish between a contradiction (having a pair of statements which one is the negation of the other) and an inconsistency (having a pair of statements which cannot both be true, but both can be false): Strawson (1952) differentiates them on logical grounds. Foley (1979) regards inconsistent beliefs as posing a serious problem, but not as serious as contradictory beliefs. Arenhart and Krause (2016) argue that quantum superpositions is an inconsistent situation, not a contradictory one. Vickers (2013) holds that it can be the case that inconsistencies in scientific theories (e.g. Bohr?s atomic theory and Newtonian cosmology) may not eventually reach a contradiction.
These all see an inconsistency as being less serious than a contradiction. In science, if an inconsistency is detected in our theories, then we can tolerate it for a bit until a solution is found. Whereas if a contradiction arises, then we need to immediately stop everything else and try to solve it. The reason is simple: classical logic, which is usually taken to be the underlying logic of (reasoning in) science, can work with inconsistencies but it cannot tolerate contradictions. A contradiction would lead to logical explosion and render the theory as useless. I concede that prima facie there is a difference between them.
I argue that an inconsistency always involves a contradiction: it is just ?hidden?. I will use an example from the history of science of an inconsistency between theory and observation (Mercury?s perihelion). It is important to say that scientists (at least in some degree) have to follow the rules of logic in their reasoning to avoid unwarranted conclusions. As Dewey put it, in a different context, ?To engage in an inquiry is like entering into a contract. It commits the inquirer to observance of certain conditions? (Dewey 1938: 16).
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