Logically possibility refers to a proposition which can be the logical consequence of another, based on the axioms of a given system of logic. The logical possibility of a proposition will depend on the system of logic being considered, rather than on the violation of any single rule. Some systems of logic restrict inferences from inconsistent propositions or even allow for true contradictions. Other logical systems have more than two truth-values instead of a binary of such values. However, when talking about logical possibility it is often assumed that the system in question is classical propositional logic. Similarly, the criterion for logical possibility is often based on whether or not a proposition is contradictory and as such is often thought of as the broadest type of possibility.