Kelvin McQueen

What physical resources are required for conscious experience? We develop a new constraint on quantum theories of consciousness by focusing on perceptual filling-in: the familiar phenomenon in which determinate colors, contours, or textures are experienced despite absent or insufficient local sensory input, as in the natural blind spot. In many such cases, the content experienced in the filled-in region reliably changes with the surrounding perceptual field. For example, when the color or texture surrounding the blind spot changes, the content experienced within the blind spot changes accordingly. We argue that producing this systematic dependence requires perceptual information to be copied with high fidelity from representations of the surrounding field into representations of the filled-in region. This creates a problem for any theory on which the relevant experiential contents are generated by coherent quantum processing. The no-cloning theorem prohibits the reliable duplication of arbitrary unknown quantum states, while approximate quantum cloning introduces substantial losses in fidelity. These obstacles disappear only when information is encoded in a stable preferred basis in which it can be reliably copied. Perceptual filling-in therefore appears to require effectively classical information-processing resources. Orchestrated objective reduction (Orch OR) provides a central test case. Orch OR proposes that biologically orchestrated quantum computations in neuronal microtubules culminate in objective-reduction events associated with moments of conscious awareness. Insofar as the determinate content of an experience is fixed by the coherent microtubule processing preceding reduction, perceptual filling-in must be implemented during that phase. Yet it is unclear how such processing could achieve the required high-fidelity copying. If, instead, classical neural mechanisms construct the filled-in content before communicating it to the quantum substrate, Orch OR must explain what indispensable role remains for quantum computation in determining the content of experience. This work extends an earlier no-cloning argument concerning deliberative agency (https://arxiv.org/abs/2510.13247) from the copying of internal world-models to the internal structure of conscious perception. The result does not imply that quantum effects are absent from the brain. Rather, it imposes a general explanatory burden on quantum theories of consciousness: they must identify where the effectively classical mechanisms required for perceptual copying enter their accounts and explain why the quantum features they invoke are not thereby rendered redundant. No-cloning constraints thus provide a new way to evaluate quantum theories of consciousness—not merely by asking whether biologically relevant quantum coherence is possible, but whether coherent quantum systems possess the information-processing resources required to generate the structured contents of ordinary experience.

Kelvin McQueen is Associate Professor of Philosophy at Chapman University. His research lies at the intersection of philosophy of physics, philosophy of mind, and the foundations of quantum mechanics. He has published on quantum measurement, interpretations of quantum mechanics, consciousness, agency, and the physical requirements for cognition. His current work investigates whether distinctively quantum systems possess the information-processing resources required for agency and conscious experience.