Beyond Cause and Effect

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Author: Denis Avetisyan

New research challenges the fundamental role of causality in physics, suggesting it may be an emergent property rather than a core law of the universe.

Prepostidictions suggest a method for anticipating future states by iteratively refining predictions based on observed discrepancies.
Prepostidictions suggest a method for anticipating future states by iteratively refining predictions based on observed discrepancies.

Quantum gravity models leveraging ‘fakeons’ indicate that strict causality is not required for a consistent physical theory.

The long-held assumption of a strict cause-effect relationship in physics faces increasing scrutiny at the quantum level. This is the central challenge addressed in ‘On Causality and Predictivity’, where we explore the implications of abandoning microcausality for consistent theories of quantum gravity, particularly those leveraging the concept of purely virtual particles. Our analysis reveals that the perceived arrow of time underpinning causality is fundamentally statistical, rendering the notion of cause a borderline concept reliant on external agents-and ultimately, a metaphysical construct rather than a physical law. If causality is not a foundational principle, what alternative frameworks might better describe the underlying reality of quantum gravity?

The Illusion of Determinism: A Universe Beyond Prediction

For centuries, the prevailing worldview in physics rested on the principle of determinism – the idea that every event is causally necessitated by prior events. This perspective, deeply ingrained in classical mechanics pioneered by figures like Newton and Laplace, envisioned the universe as a complex, yet ultimately predictable, machine. Given complete knowledge of a system’s initial conditions – the position and velocity of every particle – and the forces acting upon it, one could, in theory, calculate its entire future evolution with absolute certainty. This wasn’t merely a philosophical stance; it was a functional assumption underpinning scientific methodology, allowing researchers to confidently predict phenomena ranging from planetary orbits to the trajectory of a projectile. The universe, under this framework, wasn’t subject to chance, but unfolded with a logical, inevitable progression, a grand clockwork governed by immutable laws.

The arrival of quantum mechanics irrevocably altered the landscape of physics by demonstrating that the universe operates not on strict cause and effect, but on inherent probabilities. Unlike classical physics, where knowing initial conditions theoretically allowed for perfect prediction of future states, quantum mechanics posits that certain properties of particles exist only as a range of possibilities until measured. This isn’t simply a limitation of measurement tools; rather, the uncertainty is fundamental to the nature of reality itself, as described by the Heisenberg uncertainty principle. Instead of definite trajectories, particles are described by wave functions, representing the probability of finding them in a particular state or location. This probabilistic behavior isn’t a flaw in the theory, but a core principle, suggesting that the universe, at its most fundamental level, is not predetermined, but unfolds based on chance and statistical likelihoods, challenging long-held assumptions about determinism.

The longstanding belief in a clockwork universe, meticulously governed by cause and effect, encounters a profound challenge when confronted with the probabilistic nature of quantum mechanics. This isn’t merely a disagreement over details, but a fundamental tension in how reality operates; classical physics assumes a definite state evolving predictably, while quantum theory posits inherent uncertainties – a particle doesn’t have a definite position until measured, existing instead as a superposition of possibilities. This divergence isn’t easily reconciled, forcing physicists to grapple with the question of whether determinism is a fundamental property of the universe, or an emergent approximation valid only at macroscopic scales. The resulting philosophical and scientific debate underscores that our intuitive understanding of cause and effect, built upon everyday experience, may not accurately reflect the deeper workings of the physical world, creating a persistent puzzle at the very core of physics.

Quantum Fields and the Constraints of Locality

Quantum Field Theory (QFT) addresses the incompatibility between quantum mechanics and special relativity by describing particles as excitations of underlying quantum fields. Unlike quantum mechanics, which operates within a fixed spacetime background, QFT incorporates relativistic principles, including the constancy of the speed of light. Crucially, QFT upholds the principle of locality, meaning that an event can only be influenced by its immediate surroundings; interactions are mediated by the exchange of virtual particles and are constrained by light cones – no information or influence can travel faster than light. This is mathematically formalized through the use of commutators of field operators, ensuring that spatially separated events do not commute, and thus, cannot instantaneously affect each other. The framework avoids action-at-a-distance by describing forces not as direct interactions, but as the result of the exchange of mediating particles, such as photons in electromagnetism or gluons in the strong force.

The consistency of particle interaction descriptions within Quantum Field Theory (QFT) is maintained through specific mathematical formalisms. The Lehmann-Symanzik-Zimmermann (LSZ) reduction formalism provides a method for calculating scattering amplitudes – the probabilities of particle interactions – by relating them to vacuum expectation values of time-ordered products of field operators. Bogoliubov causality, conversely, establishes the requirement that operators representing fields at spacelike separated points must commute, ensuring that effects do not precede their causes and preventing the violation of relativistic causality. These tools are critical for constructing physically meaningful and consistent predictions within the QFT framework, allowing for the calculation of observable quantities and the elimination of unphysical solutions arising from the quantization of fields.

Despite its predictive power and experimental verification, quantum field theory remains fundamentally incompatible with general relativity, particularly when considering gravitational effects at extremely high energies or small distances. This incompatibility manifests in the non-renormalizability of gravity when treated as a quantum field theory; calculations of gravitational interactions at high energies yield infinite results that cannot be consistently removed through standard renormalization procedures. Consequently, theoretical physicists are actively pursuing extensions to, or alternatives to, conventional QFT, including string theory, loop quantum gravity, and other approaches, in an attempt to formulate a consistent theory of quantum gravity that unifies all fundamental forces and resolves the tension between QFT and general relativity.

The Breakdown of Predictability and the Search for Quantum Gravity

The pursuit of a theory of quantum gravity, attempting to unify general relativity and quantum mechanics, consistently encounters mathematical challenges that indicate a potential breakdown of deterministic predictability. Standard quantum field theory relies on unitarity – the conservation of probability – and locality – the principle that an object is only directly influenced by its immediate surroundings. However, attempts to quantize gravity result in non-renormalizable theories, requiring an infinite number of parameters to define, and frequently lead to violations of these principles. This complexity isn’t merely a matter of computational difficulty; the mathematical structures emerging from these theories suggest that the very notion of precisely predicting future states from initial conditions may not hold at the Planck scale, necessitating a revision of fundamental assumptions about causality and determinism in extreme gravitational regimes.

Fakeon Theory posits the existence of hypothetical, purely virtual particles – termed “fakeons” – which inherently violate unitarity in quantum field theory. Unitarity, a fundamental principle ensuring probability conservation, requires that the total probability of all possible outcomes equals one; fakeons circumvent this by not being subject to the usual on-shell conditions. This violation introduces non-local effects, meaning interactions are not strictly confined to the immediate spacetime vicinity. These particles, unlike real particles, do not adhere to the energy-momentum relation E^2 = p^2 + m^2, allowing for instantaneous interactions across space, effectively bypassing the limitations imposed by the speed of light and challenging conventional notions of causality within the quantum framework.

The concept of a fundamental limit to predictability in quantum gravity is supported by calculations involving a Nonlocal Lagrangian, which describes interactions beyond standard local field theory. This Lagrangian implies inherent non-locality, manifesting as delays in determining the outcome of quantum events. These delays are linked to the mass of hypothetical particles called “gravifakeons,” with estimated effects on the order of ≈ 10-37 seconds – representing a minimum Time Resolution Limit. This suggests that, even with complete knowledge of a system’s initial conditions, precise prediction of its future state is fundamentally unattainable due to these non-local effects and the associated temporal uncertainty.

Beyond Prediction: A Universe Interconnected and Nonlocal

Fakeon theory introduces a radical proposition: external forces aren’t necessarily limited by the constraints of locality, suggesting interactions can occur instantaneously regardless of distance. This challenges conventional understandings of physics, where all interactions are mediated by fields propagating at or below the speed of light. The theory posits the existence of ‘fakeons’ – hypothetical particles exhibiting this nonlocal behavior – and proposes that their interactions aren’t governed by the usual rules of cause and effect. Instead, these forces could potentially influence events across vast cosmic distances without any measurable delay, implying a deeper interconnectedness within the universe than previously imagined. While still largely theoretical, the exploration of fakeons offers a novel pathway for resolving inconsistencies in current models and potentially unifying quantum mechanics with general relativity by bypassing the need for strict microcausality.

The notion that predictability fails within certain quantum scenarios does not necessitate acceptance of inherent randomness in the universe. Instead, contemporary theoretical physics increasingly suggests a fundamental interconnectedness, where events are not isolated but rather participate in a web of relationships extending beyond conventional spatial and temporal boundaries. This perspective proposes that apparent unpredictability arises not from chance, but from the complex interplay of influences operating within this interconnected system – a holistic view where the state of one element is intrinsically linked to the states of others, potentially across vast distances. Such a framework implies that what appears as an unpredictable event may, in fact, be a consequence of subtle, nonlocal correlations, demanding a shift away from viewing the universe as a collection of independent parts and toward recognizing it as a unified, dynamically interwoven whole.

The conventional understanding of causality, where every effect has a preceding, localized cause, faces increasing scrutiny within theoretical physics. This work proposes that a consistent framework for quantum gravity may require relinquishing the principle of microcausality – the idea that events are strictly ordered in time. Instead, the universe may operate on a principle of interconnectedness where influences aren’t necessarily bound by immediate temporal proximity. The paper suggests that prepostdictions – effects seemingly preceding their causes – are not violations of physical law, but rather a natural consequence of nonlocal interactions, manifesting as delays on the order of approximately 10-37 seconds. This challenges the deeply ingrained assumption of linear time and suggests a universe where the past, present, and future are more fluidly connected than previously imagined, potentially resolving inconsistencies within current models attempting to unify quantum mechanics and general relativity.

The exploration of fakeons within quantum gravity, as detailed in the article, challenges conventional understandings of temporal order and, consequently, causality. This resonates with Paul Feyerabend’s assertion: “Anything goes.” The paper posits that models needn’t adhere to strict microcausality for internal consistency, implying a flexibility in how physical laws are constructed. One asks: what does this loosening of causal constraints tell us about the model’s underlying assumptions? The study suggests causality isn’t a foundational principle, but rather a potentially emergent property or even a useful fiction-a perspective consistent with Feyerabend’s epistemological anarchism and the idea that methodological rigidity can hinder scientific progress. Experiments probing the behavior of these models will reveal whether such a departure from traditional causality is indeed viable.

Beyond Cause and Effect

The suggestion that causality might not be a foundational principle, but rather an emergent property-or even a convenient fiction-demands a recalibration of predictive methodologies. Current approaches to quantum gravity, particularly those embracing the seemingly paradoxical nature of fakeons, implicitly operate under a different logic. A continued focus on these models, coupled with a rigorous examination of nonlocality, could reveal whether predictability arises from a deeper, acausal structure, or if it is simply a statistical consequence of constraints yet to be fully understood. The principle of microcausality, so long held as sacrosanct, appears increasingly vulnerable.

It is worth noting that visual interpretation requires patience: quick conclusions can mask structural errors. The pursuit of a fully deterministic framework, predicated on identifying a ‘first cause’, may be a misdirection. A more fruitful avenue might lie in characterizing the limits of predictability, defining the boundaries where acausality manifests, and accepting that the universe may not be fundamentally concerned with ‘why’, but only with ‘what’.

Future research should prioritize the development of observational tests, however indirect, that can distinguish between causal and acausal quantum gravity models. Such tests may not confirm or deny causality itself-that may be beyond the scope of empirical science-but could reveal whether a universe operating without strict causality is consistent with the observed physical reality.

Original article: https://arxiv.org/pdf/2601.06346.pdf

Contact the author: https://www.linkedin.com/in/avetisyan/

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2026-01-13 19:25