Book Chapter

Laws of Non-Contradiction, Laws of the Excluded Middle, and Logics

G Restall

The Law of Non-Contradiction | Oxford University Press | Published : 2010


There is widespread acknowledgement that the law of non-contradiction (LNC) is an important logical principle. However, there is less-than-universal agreement on exactly what the law amounts to. This lack of clarity is brought to light by the emergence of paraconsistent logics in which contradictions are tolerated: from the point of view of proofs, not everything need follow from a contradiction. From the point of view of models, there are 'worlds' in which contradictions are true. In this sense, the LNC is violated in these logics. However, in many paraconsistent logics, statement <(A & View full abstract