Chapter 5. Laplacean Causalism in Quantum Physics

Raphael Neelamkavil

Raphael Neelamkavil

Jiaqing Yan

Modern physics has long held two opposing extreme viewpoints. Laplacean omniscient determinism states that once all initial conditions of a system are mastered, every future evolution state can be deduced. The intrinsic randomness interpretation in quantum mechanics attributes phenomena that cannot be precisely predicted to inherent randomness at the fundamental level of the universe. Based on the pure theoretical logic of bidirectional dynamic coupling among variables, this paper carries out analysis and argumentation. It proves that the universe strictly obeys the law of causality, and the objective evolution outcome possesses unique determinacy. System variables continuously interact and rewrite the states of one another in real time. This characteristic theoretically excludes the possibility of omniscient prediction. This paper endorses the core proposition of Einstein’s causal realism, distinguishes objective causal determinacy from the theoretical boundary of deductive capability. It points out that the quantum probability interpretation confuses cognitive limitation with the intrinsic property of matter. It also explains the resource tradeoff logic of approximate models in practical applications, and establishes a unified and self consistent framework for understanding causality in fundamental physics.

David Thomas Pegg

James Vafiadis

Ernst Cassirer's Determinism and Indeterminism in Modern Physics (DI; Cassirer, 1936/1956) constitutes a major but systematically overlooked transformation in the philosophy of quantum mechanics. Against interpretations that treat the text as a late application of his earlier structuralism, this article argues that quantum mechanics forces a fundamental reconstruction of causal order and scientific objectivity. Following the dissolution of Laplacean determinism, causality is no longer directed at ‘things’ in the world, but functions as a regulative demand that experience be rendered intelligible. Accordingly, causal order does not map to a pre-given reality but is progressively constituted from within experience through recursive processes of functional co-ordination (Zuordnung). This reconstruction culminates in a participatory account of objectivity organised through three mutually conditioning levels – measurements, laws, and principles. The upshot is that physical objects emerge as invariant nodes within relational structure; objects are fixed as objective relations. On this basis, the article shows that neither epistemic nor ontic structural realism adequately captures Cassirer's position and develops in response a provisional functional ontology in which a co-ordinating subject and an indeterminate relational domain jointly constitute the transcendental conditions of objectivity. The article concludes by situating DI within a broader participatory tradition in the foundations of physics, arguing that Cassirer's recursive and observer-dependent account of objectivity anticipates key developments in second-order cybernetics and participatory approaches to quantum mechanics.

Manuel Bernardo Muñoz Bastias

This chapter completes the physical groundwork of the thesis by examining quantum mechanics, the second of the two theories that the following chapters interpret philosophically. Rather than offering an exhaustive mathematical treatment, it selects the concepts required to follow the two transversal principles identified in Chapter 3: causality and the principle of stationary action. It presents the emergence of the quantum of action, the formal structure of the theory (states, observables, Born’s rule, Schrödinger dynamics, superposition and entanglement), the double-slit experiment, the uncertainty principle, the measurement problem, and the sequence formed by the EPR argument, Bell’s theorem and its experimental tests. Using the three senses of causality distinguished in Chapter 3, the chapter shows that Heisenberg’s 1927 attempt to refute the law of causality did not succeed: unitary evolution preserves dynamical determination at the level of the quantum state, while the no-signalling condition and relativistic microcausality preserve causal precedence and causal propagation, even though Bell-local models fail. It then shows that action, present at the very birth of the theory as Planck’s quantum of action, governs quantum dynamics through Feynman’s path integral and Schwinger’s quantum action principle, and that the classical principle of stationary action re-emerges in the classical limit. The principal result, restricted to physics, is that causality and stationary action are transversal to classical, relativistic and quantum physics, although their mathematical formulation changes. Ontological conclusions are reserved for the following chapters.