A theory of negation so that for a formula , the content of its negation  ‘cancels’ that of , entailing that a conjunction  or an inconsistent set of premisses has no content, i.e., entails nothing. If the claim that an inconsistent set of formulae  is construed as the property that  has no consequences, then a deductive system with a cancellation negation will not observe the principle of explosion. Hence, cancellation negation is an example of a semantic notion that leads to paraconsistent logic independently of, e.g., considerations of dialetheism.