The Limit and Its Ground. QBism, Scientific Realism, and the Born Rule

Title:The Limit and Its Ground. QBism, Scientific Realism, and the Born Rule

Abstract:QBists insist that theirs is a realist position while denying that the quantum formalism represents a mind-independent world. The insistence is hard to place. The realism debate is throughout a dispute about represented content, so a theory that denies standing in the representation relation appears not to take up a position within that debate at all. This paper examines the most developed attempt to make good on the QBist claim--David Glick's perspectival normative realism--and argues that it fails instructively. Glick seeks the ground of the Born rule's objectivity among states of affairs and construes an agent's perspective as a location within an already-constituted world; finding no state of affairs fit to bind every agent at once, he must book the ground as brute. Phenomenology supplies the third thing his picture lacks. A horizon is not a position within the world but the condition under which a world is given. Read as an agent's weighting--her curvature--of such a horizon, the quantum state is neither a defective description nor a brute posit, and the Born rule articulates the invariant lawfulness by which any sense confers a curvature at all.

Quantum Physics (quant-ph); History and Philosophy of Physics (physics.hist-ph)

arXiv:2609.22159 [quant-ph]

(or arXiv:2609.22159v1 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2609.22159 Focus to learn more arXiv-issued DOI via DataCite

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