The Logic and Metaphysics Workshop will meet on May 10th from 10:00-4:00 (NY time) in-person at the Graduate Center (Kelly Skylight Room) for a special Wednesday session. The program:

10:00-11:30: Heinrich Wansing (Bochum)

**Title**: Quantifiers in connexive logic (in general and in particular)

**Abstract**: Connexive logic has room for two pairs of universal and particular quantifiers: one pair are standard quantifiers; the other pair are unorthodox, but we argue, are well-motivated in the context of connexive logic. Both non-standard quantifiers have been introduced previously, but in the context of connexive logic they have a natural semantic and proof-theoretic place, and plausible natural language readings. The result are logics which are negation inconsistent but non-trivial.

*Note: This is joint work with Zach Weber (Otago).*

11:30-12:30: Lunch

12:30-2:00: Daniel Skurt (Bochum)

**Title**: RNmatrices for modal logics

**Abstract**: In this talk we will introduce a semantics for modal logics, based on so-called restricted Nmatrices (RNmatrices). These RNmatrices, previously used in the context of paraconsistent logics, prove to be a versatile tool for generating semantics for normal and non-normal systems of modal logics. Each of these semantics have sound and complete Hilbert-style calculi. The advantage of RNmatrices is that they provide a unifying framework for modal logics with or without first-order Kripke-frame conditions.

*Note: This is joint work with Marcelo Coniglio (Campinas) and Pawel Pawlowski (Ghent).*

2:00-2:30: Break

2:30-4:00: Mark Colyvan (Sydney/LMU)

**Title**: Explanatory and non-explanatory proofs in mathematics

**Abstract**: In this paper I look at the contrast between explanatory and non-explanatory proofs in mathematics. This is done with the aim of shedding light on what distinguishes the explanatory proofs. I argue that there may be more than one notion of explanation in operation in mathematics: there does not seem to be a single account that ties together the different explanatory proofs found in mathematics. I then attempt to give a characterization of the different notions of explanation in play and how these sit with accounts of explanation found in philosophy of science.