Defeasible reasoning

In logic, defeasible reasoning is a kind of reasoning that is rationally compelling, though not deductively valid.. In other words, it is reasoning that is strong enough to accept as correct and true, even though it is based on premises that in strict sense have not been demonstrated to be exhaustive and/or deductively valid themselves, and thus at least in theory the defeasible argument could be shown to be false. In logic, defeasible reasoning is a kind of reasoning that is rationally compelling, though not deductively valid.. In other words, it is reasoning that is strong enough to accept as correct and true, even though it is based on premises that in strict sense have not been demonstrated to be exhaustive and/or deductively valid themselves, and thus at least in theory the defeasible argument could be shown to be false. An easy example would be the statement ″the sun will rise tomorrow″. Although many reasons could be devised for which that statement could turn out to be false (the Earth could stop turning, aliens could destroy the Sun with their star-killer doomsday weapon, the universe might be a simulation and could be shut down, etc.), and in fact it is known that it will not be true forever (since the Sun will eventually become a red giant, engulf Earth, and then become a white dwarf), none of these arguments are rationally compelling for practical reasoning, making it indistinguishable in practice from a strictly true statement. The statement ″the sun will rise tomorrow″ is thus defeasible. Defeasible reasoning is a particular kind of non-demonstrative reasoning, where the reasoning does not produce a full, complete, or final demonstration of a claim, i.e., where fallibility and corrigibility of a conclusion are acknowledged. In other words, defeasible reasoning produces a contingent statement or claim. Other kinds of non-demonstrative reasoning are probabilistic reasoning, inductive reasoning, statistical reasoning, abductive reasoning, and paraconsistent reasoning. Defeasible reasoning is also a kind of ampliative reasoning because its conclusions reach beyond the pure meanings of the premises.