  The central deducibility relation of ultramodal logics, entailment, is intended to capture the notion of sufficiency … of the antecedent of an entailment on its own, without any additional imported truth, especially imported logical truths. … Sufficiency is a go-anywhere notion, which is not limited by the fact that the situation in which it operates is somehow classically incoherent, e.g., inconsistent or paradoxical. If \(A\) is sufficient for \(B\) then it does not matter what else goes on; logical laws may go haywire but nothing subtracts from \(A\)’s sufficiency (1977, 896).