Third-Person Epistemology: Information Isomorphism Epistemology and the Objective Foundation of Testability —From "I Think" to "Anyone Running the Code": How an Ontological Fact, Rigorously Calibrated on Truth-Known Systems, Proactively Verified on T

This paper argues that Information Isomorphism Epistemology completes a paradigm shift in epistemology from the first person to the third person. Since Descartes, epistemology has been constructed in the first person—"I think," "I posit," "I see." When two "I"s reach conflicting conclusions, there is no public procedure to adjudicate. Information Isomorphism Epistemology is constructed in the third person: anyone, anywhere, downloading the publicly available data and running the same code, will obtain the same regime-switching structures. The argument proceeds from four mutually independent and mutually reinforcing pillars. First Pillar: The 2D Ising exact solution—the Chow F achieves a globally unique maximum at the precise phase transition temperature, with a deviation strictly zero in the analytic sense. Second Pillar: The 3D Ising double-peak fission—the algorithm, without any physical knowledge, proactively discovered a regime-switching structure previously unknown. Third Pillar: Cross-disciplinary emergence—the Factor Hierarchy Law has emerged repeatedly across six completely independent disciplines. Fourth Pillar: Tool replaceability—eight tools based on entirely different mathematical principles all converge near the confirmed breakpoints. These four pillars jointly point to a verified ontological fact: correct propositions leave detectable traces in statistical structures. From this fact, a criterion is derived: an epistemological system that makes factual claims about the empirical world must itself be testable. The legitimacy of this criterion does not derive from conceptual analysis but from the objective foundation jointly supported by these four pillars. Judged by this criterion, Descartes' "I think," Kant's "the thing-in-itself is unknowable," and Popper's falsifiability standard—all three have failed, in practice, to provide any public procedure satisfying the standard of traceability. Then, judged by the same criterion, Information Isomorphism Epistemology itself—each of its four components makes factual claims about the world, and each has passed the proposer's self-test. Information Isomorphism Epistemology is equally strict with itself, provides explicit falsification conditions, and bears the risk of being empirically overturned. Research Paradigm Statement: The core methodology, research direction, and final decisions were independently directed by the author. DeepSeek assisted with code implementation, data presentation, and text drafting. The author takes full academic responsibility for the final content.