Exceptionalist and Anti-Exceptionalist Perspectives on Logic

June 19-20, 2019
Edelstein Center for the History and Philosophy of Science

The S.H. Bergman Center for Philosophical Studies

The Language, Logic and Cognition Center

The Hebrew University of Jerusalem

Day 1 19.6.2019
9:30-10:00 Gathering, refreshments

10:00-11:00 Graham Priest (CUNY), Anti-Exceptionalism and Logical Pluralism
The paper concerns the bearing of anti-exceptionalism on logical pluralism. Does it rule it out? If not, how does it apply to it, and what is the outcome? The paper does not aim to settle all these questions, but simply to open up a discussion of the matter.

11:00-11:15 Coffee break

11:15-12:15 Ole Hjortland (University of Bergen), Anti-Exceptionalism and Explanations in Logic (joint work with Ben Martin)
According to logical anti-exceptionalism we come to be justified in believing logical theories by similar means to scientific theories. This is often explained by saying that theory choice in logic proceeds via abductive arguments (Priest, Russell, Williamson, Hjortland). Thus, the success of classical and non-classical theories of validity are compared by their ability to explain the relevant data. However, as of yet there is no agreed upon account of which data logical theories must explain, and subsequently how they prove their mettle. In this paper, we provide a non-causal account of logical explanation, and show how it can accommodate important disputes about logic.

12:15-13:30 Lunch

13:30-14:00 Short tour at the Einstein Archive (guided by Prof. Yemima Ben Menahem)

14:15-15:15 Ulf Hlobil (Concordia University), Forging Expressive Tools, not Explanations: On the Freedom of a Logician
The central claim of anti-exceptionalism about logic is that theory choice in logic ought to happen by abduction, i.e., we ought to accept the logical theory that offers the best overall balance of relevant theoretical virtues. In particular, anti-exceptionalists claim that one such theoretical virtue is that a logical theory captures or explains as much as possible of the relevant data. I argue that anti-exceptionalists haven’t been careful enough in addressing the following three questions: (a) What is the point or aim of a logical theory? (b) What are the relevant data? (c) What is the relation between natural language and the languages studied in logic? Drawing on logical expressivism and in contrast to anti-exceptionalism, I suggest that logic is not in the business of offering explanations. Rather, logic is in the business of inventing and exploring artificial expressions that allow us to capture (in the object language) various features of (primarily) non-logical consequence and incompatibility. This view preserves the insights of anti-exceptionalism, such as the importance of abduction in logic, while leaving room for the freedom of logicians to invent and study entirely new logical expressions that have no analogues in natural language.

15:15-15:30 Coffee break

15:30-16:30 Rea Golan (Hebrew University of Jerusalem), How Logic Can be Normative for Reasoning
I aim to defend the position that logic can be normative for reasoning. The purpose of the talk is twofold. Primarily, I argue that Gilbert Harman’s well-known challenges to the normativity of logic, as well as the bridge principles method that is adopted by many to respond to them, all rest on the unjustified assumption that the mere form of a given deductive inference can determine its normative significance to one’s reasoning. As a secondary goal, I aim to outline an alternative account of logic as, by its very nature, normative for reasoning.

19:00-22:00 Dinner

Day 2 20.6.2019
9:00-9:30 Gathering, refreshments

9:30-10:30 Stewart Shapiro (Ohio State University, UConn), Science and logic: logic and science (joint work with Marcus Rossberg)
Our goal here is to take the measure of various exceptionalist and anti-exceptionalist theses, and to delimit the extent which they capture work traditionally belonging to logic.

10:30-10:45 Coffee break

10:45-11:45 Gil Sagi (Haifa University), Explicating Logical Consequence
Carnapian explication, in the paradigmatic case, takes an informal scientific concept and replaces it with a formal one couched in a formal system. This system will have a formal consequence relation. What about the relation of logical consequence itself? Two salient options present themselves. One is treating logical consequence as serving a methodological role in the systematisation of science. Another, is studying logical consequence itself as a scientific concept to be explicated. For the latter option, I suggest that the relevant science is linguistics, and I propose an explication that is in line with current practice in natural language semantics.

11:45-12:00 Coffee break

12:00-13:00 Jack Woods (University of Leeds), Generic Validity
Until 15 years ago, it would have been very difficult to deny that there was a most basic, foundational, or fundamental relation of logical consequence. These days, though, logical pluralism is on the rise and some have even made the stronger claim that no notion of logical consequence holds across all contexts. Yet many of us still hold onto the thought that there really is one most basic, foundational, fundamental notion of logical consequence which underlies all the rest. I argue that there is a basic notion of logical consequence; it’s the relation which plays the functional role of specifying which logic best serves an instrumental purpose and adjudicating disputes between logics. Without such a notion, in fact, it’s hard to know why we should take arguments about logical pluralism and logical anti-exceptionalism at all seriously.

13:00-14:00 Lunch

14:30-18:00 Tour of the Old City of Jerusalem