8 - Kripke on the Incoherency of Adopting a Logic

Summary

In 1974, Saul Kripke gave a graduate seminar at Princeton purportedly on Wittgenstein’s Philosophical Investigations, with emphasis on the role of rules in Wittgenstein’s private language argument. Before beginning this topic, Kripke said that he would first make a “few remarks” on a topic related to the central point of Wittgenstein’s discussion of “rule-following,” namely, the topic of “adopting a logic.” Kripke chose to address some other related questions. They included his views on whether it is coherent to “have a logic” or for there to be an “alternative logic.” He also concentrated on the more restrictive thesis of whether there is a nontrivial, “non–garden variety” way in which one can “revise logic.” These “few remarks” took up the entire seminar, with many classes running more than one hour over the three hours allotted to each class.

In Section I, we discuss Kripke’s general objections to the notion of adopting a logic. In Section II, we consider a part of logic that may be immune to these objections. In particular, we consider whether it is coherent to adopt “quantum logic.” In Section III, we evaluate the claim of adopting intuitionist logic. Last, in Section IV, I suggest some morals to be learned.