Information Is Not Physical: Possibility Spaces, Erasure, and the Structure of Unrealized Alternatives

Abstract:The slogan ``information is physical,'' introduced by Rolf Landauer and developed through quantum information theory and black-hole thermodynamics, has achieved near-axiomatic status in modern physics. Yet the ontological status of information remains surprisingly underexamined: most discussions either reduce information to a form of energy or treat it as a purely mathematical object. This paper proposes a third position. I argue that information is neither a physical substance nor a free-floating abstraction, but rather \emph{the structure of physically realizable alternatives} -- a counterfactual structure that a physical system instantiates in virtue of the possibility space available to it. Building on Shannon's combinatorial definition, the Landauer principle, the no-cloning theorem, and the black-hole information paradox, I show that the informational content of any physical event is constituted by the set of outcomes that \emph{could have occurred} but did not. This counterfactual reading dissolves several persistent confusions: it explains why erasing information dissipates heat without making information ``material,'' why quantum superposition is informationally richer than any classical mixture, and why information loss in black holes is physically significant beyond mere bookkeeping. The proposal sits within a structural-realist framework but departs from standard structural realism by locating the relevant structure in modal, not merely actual, relations. I conclude by sketching implications for the foundations of quantum mechanics, quantum gravity, and scientific ontology more broadly.

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

arXiv:2606.15120 [physics.hist-ph]

(or arXiv:2606.15120v1 [physics.hist-ph] for this version)

https://doi.org/10.48550/arXiv.2606.15120 Focus to learn more arXiv-issued DOI via DataCite (pending registration)

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