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We formally define and address whether this uncertainty is unavoidable or whether post-quantum theories can offer a predictive advantage while conforming to the Born rule on average. We present a no-go claim combining three aspects: predictive advantage, no-signalling, and reliable intersubjectivity between quantum observers. The results of the analysis lead to the conclusion that there exists a fundamental limitation on genuine predictive advantage. However, we uncover a fascinating possibility: When the assumption of reliable intersubjectivity between different observers is violated, subjective predictive advantage can, in principle, exist. This, in turn, entails an epistemic boundary between different observers of the same theory. The findings reconcile us to quantum uncertainty as an aspect of limits on Nature&apos;s predictability.<\/jats:p>","DOI":"10.22331\/q-2024-11-07-1518","type":"journal-article","created":{"date-parts":[[2024,11,7]],"date-time":"2024-11-07T16:33:28Z","timestamp":1730997208000},"page":"1518","update-policy":"https:\/\/doi.org\/10.22331\/q-crossmark-policy-page","source":"Crossref","is-referenced-by-count":2,"title":["Epistemic Boundaries and Quantum Uncertainty: What Local Observers Can (Not) Predict"],"prefix":"10.22331","volume":"8","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8973-0373","authenticated-orcid":false,"given":"Johannes","family":"Fankhauser","sequence":"first","affiliation":[{"name":"Institute for Theoretical Physics, University of Innsbruck, Technikerstra\u00dfe 21a, 6020 Innsbruck, Austria"},{"name":"Faculty of Philosophy, University of Oxford, Woodstock Road, Oxford OX2 6GG, UK"}]}],"member":"9598","published-online":{"date-parts":[[2024,11,7]]},"reference":[{"key":"0","unstructured":"Johannes Fankhauser. ``Observability and predictability in quantum and post-quantum physics''. 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