Adopting and rejecting logic

Abstract

It is well known that there are, surprisingly enough, alternative logics. Not all logics obey classical logic. One or the other basic laws of classical logic – like excluded middle - can always be challenged and a different logic can be developed. Sometimes this revision takes place because of developments in science. Putnam (1968) argued that classical logic cannot be accepted for quantum mechanics. This implies that we can adopt a different logic when it comes to quantum mechanics. Putnam’s claim supports Quine’s notion that nothing is exempt from revision under empirical pressure. Contrary to this, Kripke (2023) argues that we cannot adopt a logic which deviates from a basic principle like the law of excluded middle. Since, we cannot adopt a logic we cannot change our reasoning because of pressure from empirical sciences. In this paper, I will raise the issue of whether we can reject a logic or not and what implications this can have for logic, reasoning and Quinean anti-exceptionalism about logic. In short, I will argue that we cannot reject a logic, but we can revise classical logic and develop a different formal system but this does not imply that the original logic was somehow just like the sciences, open to rejection. In this sense, logical systems are not like Ptolemaic models of the solar system. I will also maintain that it is hard to say what logic our reasoning employs, and that revision is not the anvil on which the apriority of logic should be tested.