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.