CEFISES Seminar: Peter Verdee, “Multiperspectival supervaluationism and deep indeterminacy”

Livestream https://youtube.com/live/UCp-2m91w8k

Series: OLOFOS

Speaker: Peter Verdee (UCLouvain)

Title: “Multiperspectival supervaluationism and deep indeterminacy”

Abstract

In this talk, we present a novel approach to addressing indeterminacy, inspired by supervaluationism. Our investigation begins with Bradford Skow’s argument (cf. [1]) for the conceivability of deep metaphysical indeterminacy, grounded in the Kochen-Specker theorem from quantum mechanics. The central idea is that, unlike cases of shallow indeterminacy, where a supervaluationist framework diagnoses indeterminacy as the impossibility to select among multiple consistent assignments of truth values to propositions (cf. [2]), deep indeterminacy involves situations in which no such consistent assignment is possible.

To model such cases, we propose a formal framework based on truthmaker semantics. This model partitions language into distinct fragments, each representing a consistent way of specifying reality. States are conceived as potentially incomplete and/or inconsistent containers of information, serving as verifiers or falsifiers of sentences. We introduce a binary relation of admissible extension between states, which enables the definition of superverification and superfalsification—truth or falsity across all admissible extensions.

We will present the formal model, demonstrate its compatibility with quantum logic, and explore its broader applicability beyond quantum indeterminacy. In particular, we suggest that this framework may illuminate reasoning in contexts where open problems in science or mathematics are best understood through multiple precise yet mutually incompatible perspectives each offering insight, but not integrable into a single global language.

References
[1] Skow, B. (2010). Deep metaphysical indeterminacy. The Philosophical Quarterly, 60(241), 851–858.
[2] Barnes, E., & Williams, J. R. G. (2011). A Theory of Metaphysical Indeterminacy. In D. Zimmerman & K. Bennett (Eds.), Oxford Studies in Metaphysics (Vol. 6, pp. 103–148). Oxford: Oxford University Press.