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Timing & Time Perception

The Nature of Time in Relativistic Operational Reality

Diederik Aerts, Massimiliano Sassoli de Bianchi

Published Jan 18, 2024• 5 citations
Publisher

Abstract

Abstract In their recent articles Gruber, Block and Montemayor (2022: Front. Psychol., 13, 718505) and Buonomano and Rovelli (2022: arXiv:2110.01976) discuss the differences between time in physics and psychology. With the aim of commenting on their views, we first outline a few general aspects of relativity theory, and some of the core elements of our approach, referring the reader to Aerts (1996: Found. Phys., 26, 1627–1644; 2018: Found. Sci., 23, 511–547), Aerts and Aerts (2004: in A. C. Elitzur, S. Dolev and N. Kolenda (Eds), Quo Vadis Quantum Mechanics? Possible Developments in Quantum Theory in the 21st Century, pp. 153–207) and Aerts and Sassoli de Bianchi (2023: arXiv:2307.04764) for more details. In our approach, the ability of the experimenter to freely choose to perform or not to perform an experiment is explicitly considered and applied to the typical twin-paradox situation. This leads to the definition of a four-dimensional spacetime reality for each observer, a personal block universe. This is compatible with the existence of a local contextual present for each observer, travelling on their worldline, from their personal past to their personal future. Global spacetime becomes, as a corollary, a structure full of measurement-induced bifurcations towards the future, thus fundamentally nondeterministic. We analyze and highlight how this nondeterministic global reality is the one that follows from an operational approach inspired by quantum foundations, opening a way for an integration of relativity and quantum.

DOI
10.1163/22134468-bja10102

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Abstract In their recent articles Gruber, Block and Montemayor (2022: Front. Psychol., 13, 718505) and Buonomano and Rovelli (2022: arXiv:2110.01976) discuss the differences between time in physics and psychology. With the aim of commenting on their views, we first outline a few general aspects of relativity theory, and some of the core elements of our approach, referring the reader to Aerts (1996: Found. Phys., 26, 1627–1644; 2018: Found. Sci., 23, 511–547), Aerts and Aerts (2004: in A. C. Elitzur, S. Dolev and N. Kolenda (Eds), Quo Vadis Quantum Mechanics? Possible Developments in Quantum Theory in the 21st Century, pp. 153–207) and Aerts and Sassoli de Bianchi (2023: arXiv:2307.04764) for more details. In our approach, the ability of the experimenter to freely choose to perform or not to perform an experiment is explicitly considered and applied to the typical twin-paradox situation. This leads to the definition of a four-dimensional spacetime reality for each observer, a personal block universe. This is compatible with the existence of a local contextual present for each observer, travelling on their worldline, from their personal past to their personal future. Global spacetime becomes, as a corollary, a structure full of measurement-induced bifurcations towards the future, thus fundamentally nondeterministic. We analyze and highlight how this nondeterministic global reality is the one that follows from an operational approach inspired by quantum foundations, opening a way for an integration of relativity and quantum.
An operational approach to quantum mechanics has been developed in the past decades in our group in Brussels. A similar approach is taken in this work, making use of the extra operational depth offered by this approach, to show that the construction of spacetime is specific to each observer. What is usually referred to as the block universe then emerges by noting that parts of the past and future are also contained in the present, but without the limitations that a four-dimensional block universe usually implies, of a reality in which change would be impossible. In our operational approach, reality remains dynamic, with free choice playing a central role in its conceptualization. We also show that, when operationally analyzed, the theory implies that objects move not only in space, but also and especially in time, and more generally in spacetime, with their rest mass being a measure of their kinetic time energy. We therefore claim that Einstein’s relativity revolution has not been fully realized, since most physicists are not ready to accept these consequences of the theory although the formula’s showing them, when operationally analyzed, are in every relativity textbook. In particular, when relativistic motion is revisited as a genuine four-dimensional motion, it becomes possible to reinterpret the parameter c associated with the coordinate speed of light, which becomes the magnitude of the four-velocity of all material entities. We observe that this four-dimensional motion in Minkowski space can also be better understood if placed in the broader perspective of quantum mechanics, provided that non-locality is interpreted as non-spatiality, thus indicating the existence of an underlying non-spatial reality, the nature of which could be conceptual, consistent with the conceptuality interpretation of quantum mechanics. This hypothesis is reinforced by noting that when observers, or experiencers, as they will be referred to in this article, are described by acknowledging their cognitive nature of entities moving in a semantic space, Minkowski metric emerges in a natural way.
Advances in our understanding of the physical universe have dramatically affected how we view ourselves. Right at the core of all modern thinking about the universe is the assumption that dynamics is an elemental feature that exists without question. However, ongoing research into the quantum nature of time is challenging this view: my recently introduced quantum theory of time suggests that dynamics may be a phenomenological consequence of a fundamental violation of time reversal symmetry. I show here that there is consistency between the new theory and the block universe view. I also discuss the new theory in relation to the human experience of existing in the present moment, able to reflect on the past and contemplate a future that is yet to happen.This article is part of a discussion meeting issue 'Foundations of quantum mechanics and their impact on contemporary society'.
In the previous chapters, we have made an imaginary travel in a ship which we might call “time” for analyzing how this concept is present in the physical theories which describe our world and the diverse interactions which make possible its existence as we perceive it under our notion of reality. We have traveled from the submicroscopic scale—requiring a quantum description— up to the cosmological dimensions where gravity acquires a crucial role distorting the space-time of the special relativity theory. In this chapter, we discuss some of the most recent publications related to physical theories about time, starting with the cellular automation interpretation of quantum mechanics (QM) formulated by Gerard’t Hooft, where information loss is considered as the cause of the time-reversal asymmetry. Then we continue with the thermal time hypothesis of Carlo Rovelli, who asserts that it is possible to formulate classical mechanics in a way in which the time variable is treated on equal footing as other physical variables, and not considered as a special and independent variable. Afterward, we analyze theories which propose quantization of time, and then continue with the discussion of proposed time operators for non-relativistic and relativistic QM. At the end of that section, we discuss theories related with time in quantum gravity and then we briefly explore in the physics of time travel.
Modern quantum mechanics, despite its relativistic extensions, provides intriguing support for a present-centered view of time. This paper argues that quantum phenomena – indeterminacy, wavefunction collapse, the Born rule, and temporal asymmetries in measurement – challenge the static block universe of eternalism and instead elevate the present moment to ontological prominence. Remaining largely interpretation-neutral, we draw on a range of perspectives (from Einstein’s relativity to collapse models, and thinkers like Heisenberg, Rovelli, Maudlin and others) to show that quantum theory operationally distinguishes past, present, and future in a way classical physics did not. We examine how the measurement problem and the randomness of quantum outcomes resist a fully eternalist description, highlight how quantum mechanics introduces an arrow of time at a fundamental level, and consider proposals (e.g. GRW theory, delayed-choice experiments) that make a global present – or something akin to it – conceptually necessary. Classical philosophers and physicists from Einstein to Schrödinger are discussed alongside contemporary voices. While stopping short of endorsing any single ontology outright, we contend that the empirical success of quantum theory re-opens the case for presentism or related “A-theoretic” models of time. In closing, we introduce Existential Realism as a novel metaphysical framework aligning with these insights – one which preserves the special status of the present while accommodating the reality of past and future in a more dynamic ontology. The result is a rigorous yet accessible interdisciplinary inquiry: quantum physics, we conclude, prefers the present, suggesting time’s passage and the now are more than mere illusions.[1] [1] https://quoteinvestigator.com/2024/03/18/stubborn-illusion/#:~:text=%3E%20On%20Michele%20Besso%20%281873,245
This paper examines the possibility that past and future events are fundamentally alike in their ontological openness, while differing in their causal accessibility. The conventional distinction between a fixed past and an open future becomes problematic in light of the relativity of simultaneity, which provides no universal present at which openness could turn into ontological definiteness. As an alternative to the fully determined history of a block universe, the paper considers a symmetric conception in which neither past nor future is necessarily ontologically invariant. The proposed distinction separates ontological openness from causal accessibility. While past events cannot be influenced from our present position, parts of the causal future remain accessible to intervention. This asymmetry is compatible with the invariant causal structure of relativistic spacetime and does not require a universal transition from openness to definiteness. Schrödinger's cat provides a further illustration. If the cat is found dead and already in rigor mortis, the observed traces indicate an earlier death. Nevertheless, this does not by itself establish when the corresponding history became ontologically definite. The paper explores the possibility that a later measurement may be associated with the ontological articulation of an earlier, causally ordered history, without requiring backward causation. The argument is situated in relation to relational quantum mechanics, Wheeler's delayed-choice experiments, and philosophical discussions of retrocausality. The paper does not claim to prove an ontologically open past. Rather, it develops this possibility as a serious philosophical alternative to an invariant block universe, distinguishing physical evidence from ontological interpretation and clarifying the conceptual limits of what can be established.