This paper resolves the measurement problem and the problem of intersubjectivity—two foundational puzzles of quantum mechanics—within the Planck Core Framework, without requiring any additional postulates beyond the three axioms of the framework. I prove that measurement is not a mysterious non-unitary "collapse" of the wavefunction, but a unitary process of entanglement establishment between subsystems of the quantum bit network. The apparent collapse arises from the observer's limited access to the full entanglement structure: what we perceive as a definite measurement outcome is simply our location within a specific entanglement branch. The Born rule is derived, not postulated—the probability of an outcome is proportional to the number of entanglement threads in the corresponding branch. The Wigner's friend paradox is resolved by proving that different observers may occupy different branches, but their descriptions converge when they exchange information via entanglement. I further introduce the concept of the "information eye"—a hypothetical direct entanglement sensor—and prove that any macroscopic biological organism operating at biological temperatures will inevitably perceive a decohered, classicalised representation of reality, not the underlying quantum information network itself. The classical appearance of the macroscopic world is thus derived as a contingent consequence of thermodynamic constraints on biological evolution, not a fundamental feature of reality. This work completes the derivation of quantum mechanics from the Planck Core Framework, establishing that no special measurement postulate is required.
This paper resolves the measurement problem and the problem of intersubjectivity—two foundational puzzles of quantum mechanics—within the Planck Core Framework, without requiring any additional postulates beyond the three axioms of the framework. I prove that measurement is not a mysterious non-unitary "collapse" of the wavefunction, but a unitary process of entanglement establishment between subsystems of the quantum bit network. The apparent collapse arises from the observer's limited access to the full entanglement structure: what we perceive as a definite measurement outcome is simply our location within a specific entanglement branch. The Born rule is derived, not postulated—the probability of an outcome is proportional to the number of entanglement threads in the corresponding branch. The Wigner's friend paradox is resolved by proving that different observers may occupy different branches, but their descriptions converge when they exchange information via entanglement. I further introduce the concept of the "information eye"—a hypothetical direct entanglement sensor—and prove that any macroscopic biological organism operating at biological temperatures will inevitably perceive a decohered, classicalised representation of reality, not the underlying quantum information network itself. The classical appearance of the macroscopic world is thus derived as a contingent consequence of thermodynamic constraints on biological evolution, not a fundamental feature of reality. This work completes the derivation of quantum mechanics from the Planck Core Framework, establishing that no special measurement postulate is required.
This paper has been updated by https://doi.org/10.5281/zenodo.20279031 This paper resolves the measurement problem and the problem of intersubjectivity—two foundational puzzles of quantum mechanics—within the Planck Core Framework, without requiring any additional postulates beyond the three axioms of the framework. I prove that measurement is not a mysterious non-unitary "collapse" of the wavefunction, but a unitary process of entanglement establishment between subsystems of the quantum bit network. The apparent collapse arises from the observer's limited access to the full entanglement structure: what we perceive as a definite measurement outcome is simply our location within a specific entanglement branch. The Born rule is derived, not postulated—the probability of an outcome is proportional to the number of entanglement threads in the corresponding branch. The Wigner's friend paradox is resolved by proving that different observers may occupy different branches, but their descriptions converge when they exchange information via entanglement. I further introduce the concept of the "information eye"—a hypothetical direct entanglement sensor—and prove that any macroscopic biological organism operating at biological temperatures will inevitably perceive a decohered, classicalised representation of reality, not the underlying quantum information network itself. The classical appearance of the macroscopic world is thus derived as a contingent consequence of thermodynamic constraints on biological evolution, not a fundamental feature of reality. This work completes the derivation of quantum mechanics from the Planck Core Framework, establishing that no special measurement postulate is required.
Abstract: The quantum measurement problem has been the deepest conceptual difficulty since the birth of quantum mechanics. Standard quantum mechanics accepts wavefunction collapse as an independent postulate but never provides a physical explanation. The decoherence approach attributes collapse to the interaction between the system and its environment, but faces two fundamental limitations: the “infinite regress” problem and the “insufficiency of decoherence” problem. Within the framework of the Self-Construction Theory (SCT), this paper provides a complete resolution of the measurement problem. The core thesis is that quantum measurement is not a fundamental process independent of the laws of physical evolution, but rather a local manifestation of constructive renormalization—the scale evolution of the spacetime complex field K from microscopic degrees of freedom to macroscopic effective descriptions. The origins of wavefunction collapse, decoherence, and the Born rule receive a unified first‑principles interpretation in this framework. SCT’s spontaneous decoherence mechanism is the key to the resolution. Constructive renormalization inherently involves information loss—the integrated‑out microscopic degrees of freedom no longer exist in the macroscopic effective description. During a measurement, the measuring apparatus possesses a huge number (∼1023) of microscopic degrees of freedom. When the apparatus interacts with the measured system, constructive renormalization triggers information compression of these degrees of freedom—the apparatus can no longer distinguish which branch of the superposition it is in, and quantum coherence is thus spontaneously lost. No “external environment” is needed—the constructive renormalization dynamics of spacetime itself is the ultimate source of decoherence, thereby completely solving the “infinite regress” problem. Among the probability distribution given by the Born rule, the weights of non‑maximal probability branches are further suppressed by information compression under the huge number of microscopic degrees of freedom, so that macroscopic observers can perceive only a definite outcome in the effective description. The information loss caused by constructive renormalization is ontological—it does not rely on any approximation or truncation, thus fundamentally solving the “insufficiency of decoherence” problem. The Born rule—that measurement outcomes occur with probabilities given by the squared amplitudes—is directly derived from the constructive integral structure in SCT. In the constructive renormalization limit, interference terms between different configurations are naturally suppressed by off‑diagonal phase randomization, and the system automatically switches to a classical probabilistic description. In the diagonal density matrix representation, the squared amplitude is the only natural weight that is simultaneously real and non‑negative. Hence the Born rule is not an additional postulate of quantum mechanics but a necessary and unique manifestation of the relative frequencies of the constructive integral in the constructive renormalization limit. This derivation is rigorous within the mathematical framework of constructive renormalization—it does not rely on any approximations or truncations. SCT’s quantum measurement theory is deeply unified with the black hole information paradox. The “collapse” in quantum measurement and the “information loss” in black hole evaporation are different manifestations of the same core mechanism—the redistribution of information due to constructive renormalization—in two extreme physical situations. In quantum measurement, information is redistributed into the degrees of freedom of the macroscopic apparatus; in black hole evaporation, information is redistributed into the time‑point configurations on the horizon. This unification is the strongest proof of the universality of constructive renormalization as an information‑processing mechanism. Keywords: quantum measurement; spontaneous decoherence; constructive renormalization; Born rule; wavefunction collapse; information redistribution; Self-Construction Theory
We present a complete, mathematically rigorous, and observer-free resolution of the quantum measurement problem. Building entirely on the axiomatic framework established in the preceding work, which derives the Born rule exclusively from unitary dynamics, uniqueness of classical records, unitary invariance, and ergodic stability, we show that the entire measurement process is governed by a single deterministic law: unitary evolution. The apparent wavefunction collapse is not a physical process but an effective description of the emergence of a unique dynamically stable classical record under decoherence and unique ergodicity. No auxiliary postulates, collapse mechanisms, or observer-dependent inputs are required. We explain the origin of definite measurement outcomes, the emergence of objective probability, the elimination of quantum-classical duality, and provide a fully consistent resolution of the Wigner’s friend paradox. The framework reproduces all experimental predictions of quantum mechanics without contradictions and establishes a unified, self-contained foundation for quantum measurement theory. This work constitutes the first complete, minimal, and mathematically closed solution to the quantum measurement problem.
Quantum mechanics lacks a physical definition of measurement, observer, probability, and experienced time. These notions are instead treated as primitive or interpretation-dependent, leading to persistent foundational problems including the measurement problem, the origin of the Born rule, observer disagreement in Wigner’s Friend scenarios, the arrow of time, and apparent information loss in black hole evaporation. In this work, we show that these problems share a single missing ingredient: the absence of an operational definition of observers as bounded physical systems. We define observers as physically realizable systems capable of forming irreversible internal records under unitary dynamics. Measurement is identified with record formation, probability with record redundancy, experienced time with record accumulation, and irreversibility with computational inaccessibility rather than non-unitarity. Using decoherence and quantum Darwinism, we show that the number of accessible, decoherence-stable records associated with an outcome scales with the squared amplitude, yielding the Born rule from record counting without invoking collapse, subjective probability, or additional axioms. Observer-relative paradoxes dissolve once outcome definiteness is indexed to record formation rather than to the global quantum state. Reconstruction of global quantum information is shown to require exponential resources, rendering measurement and black hole evaporation operationally irreversible despite global unitarity. The resulting framework closes quantum mechanics conceptually by eliminating undefined primitives, without modifying its mathematical structure or introducing new dynamical postulates.
Quantum mechanics famously posits two distinct evolution rules for the state of a system: a deterministic, unitary time evolution under the Schr¨odinger equation, and a probabilistic “collapse” of the wavefunction upon measurement as dictated by the Born rule. The apparent inconsistency of these two dynamical laws – one continuous and one discontinuous – constitutes the quantum measurement problem. This foundational problem, which underlies the emergence of definite outcomes from quantum superpositions, has persisted since the theory’s inception. In this review, we present a comprehensive and rigorous examination of the measurement problem and survey the leading approaches that seek to resolve or circumvent it. We begin by formulating the measurement problem and its conceptual challenges. We then discuss in detail the major interpretations of quantum mechanics and theoretical frameworks addressing the problem: the Copenhagen interpretation, Everett’s many-worlds interpretation, de Broglie–Bohm pilot-wave theory, objective collapse models, the role of decoherence and environment-induced superselection, and epistemic approaches such as QBism. For each interpretation, we describe the core principles and mathematical formalism, assessing how (and whether) it attempts to solve the measurement problem. We also review modern developments and experiments relevant to quantum measurements, including tests of Bell inequalities, observations of decoherence and macroscopic superpositions, weak measurements and quantum eraser experiments, and thought experiments ‘a la Wigner’s friend. We highlight how these results inform the ongoing debate. Finally, we discuss open problems and challenges that remain in fully resolving the measurement problem.
This paper is a conceptual and interpretive companion to "The Dynamics of Discrete Fact: A Phase-Transition Theory of Wavefunction Collapse" (doi:10.5281/zenodo.18748601), which develops a phase-transition theory of wavefunction collapse in full mathematical detail. The interpretive claims made here rest on the physical model established there. The paper identifies a structural conflation at the root of the quantum measurement problem. The standard formulation treats measurement simultaneously as a physical process and as an experiential event without distinguishing between the two. We formalize this distinction as two complementary descriptive frames — a Reality Frame (F_R) for the continuous dynamics of the system–apparatus field, and an Observer Frame (F_O) for the discrete outcomes recorded by an embedded observer — connected by a calculable critical threshold γ_c derived from the companion paper's phase-transition model. The frame distinction is applied to the three sub-problems of measurement, to five foundational paradoxes (Wigner's friend, Frauchiger–Renner, Schrödinger's cat, delayed choice, and EPR), and to seven major interpretations of quantum mechanics, each shown to privilege one frame while neglecting the other. A Frame Complementarity Principle is conjectured as a testable constraint on the simultaneous accessibility of process information and outcome definiteness.