For more than a century, gravity has been the stubborn outlier in physics, perfectly described on cosmic scales yet refusing to mesh with the quantum rules that govern everything else. A growing camp of theorists is now asking whether gravity is not a basic ingredient of nature at all, but a side effect of entropy and information, an emergent phenomenon that appears only when many microscopic degrees of freedom are taken together. If that radical idea holds up, it could recast the unification problem itself, shifting the search from a new particle or field to the hidden statistical machinery of spacetime.
Instead of treating gravity as a fundamental interaction to be quantized like electromagnetism, these approaches treat it more like the elasticity of a crystal or the pressure of a gas, a collective behavior that only makes sense at large scales. I want to trace how this entropic picture fits into the long struggle to reconcile Einstein’s General Relativity with quantum mechanics, what it might offer to a future unified theory, and why many physicists still see it as an intriguing but unproven detour rather than a destination.
Why gravity is still the odd force out
The basic problem is brutally simple: the universe runs on two rulebooks that do not match. On one side sits Einstein’s General Relativity, a geometric theory in which mass and energy curve spacetime and that curvature guides the motion of planets, stars and galaxies. On the other side is quantum mechanics, which describes particles and forces at a tiny, subatomic scale using probabilities, fields and discrete quanta. As one standard overview of unified field theory puts it, the primary difficulty is that gravity is described by Einstein General Relativity, while the other three forces fit neatly into quantum field theory.
That mismatch is not just aesthetic. When physicists try to apply quantum tools directly to the gravitational field, the equations explode into infinities that cannot be renormalized away, unlike in the successful quantum theories of electromagnetism and the nuclear forces. Experimentalists are now designing ever more sensitive experiments to probe this tension, with new proposals to test for Developing quantum gravity effects in tabletop setups and astrophysical observations. Yet no single framework has been able to reproduce both the precision tests of General Relativity and the quantum behavior of matter, which is why any fresh angle on what gravity actually is commands so much attention.
From thermodynamics to spacetime: the entropic gravity idea
Into this stalemate steps the notion that gravity might not be fundamental at all, but instead an entropic force. In this view, sometimes called Entropic gravity or emergent gravity, the attraction we attribute to mass is really a statistical tendency of microscopic degrees of freedom to rearrange toward states of higher disorder. Just as a stretched rubber band snaps back because there are more ways for its molecules to be jumbled than aligned, spacetime itself could “pull” matter along trajectories that increase entropy. In this picture, the familiar inverse square law and even Einstein’s field equations arise as large scale thermodynamic limits of some deeper quantum level disorder, not as fundamental interactions written into nature’s core.
Popular explanations have leaned on analogies to help non specialists grasp this shift. One widely watched episode of the series What If Gravity is Not a Fundamental Force walks through how Gravity might be no more fundamental than the force of a stretched elastic band, using the language of entropy and information to motivate the idea. More technical work has tried to show that starting from basic thermodynamic assumptions about information on holographic screens, one can recover Newton’s law of gravitation and aspects of General Relativity without ever postulating a gravitational field. Advocates argue that if gravity is emergent in this way, the unification problem might be reframed as understanding the microscopic quantum bits whose collective behavior we currently misinterpret as a standalone force.
Gravity from Entropy: a statistical mechanics theory of spacetime
Some of the most ambitious work in this direction goes beyond heuristic analogies and tries to build a full statistical mechanics theory of gravity. A recent formulation known as The Gravity from Entropy theory treats gravity as fundamentally a statistical mechanics theory that captures the collective behavior of microscopic degrees of freedom. In this framework, the macroscopic gravitational field is not a basic entity but an emergent description of how underlying quantum states are distributed. The authors argue that The Gravity from Entropy approach can be derived from a Hamiltonian description and then applied to cosmology, linking entropy production to the large scale evolution of the universe.
What makes this Gravity from Entropy theory notable is its insistence that spacetime geometry itself is not fundamental, but a bookkeeping device for the entropic interactions of microscopic constituents. The work describes how Entropy gradients can mimic the effects of curvature, so that what we interpret as geomet ric degrees of freedom of spacetime are really emergent variables summarizing a vast underlying state space. If that claim holds, it would mean that the same statistical tools used to describe gases and magnets could, in principle, describe black holes and cosmic expansion. For unification, that is a tantalizing prospect, because it suggests that gravity and thermodynamics might share a common language that naturally interfaces with quantum theory.
New thermodynamic models and what they can already reproduce
Other researchers are pursuing related thermodynamic routes that try to reproduce known gravitational phenomena without invoking gravity as a distinct force. One recent model starts from the laws of thermodynamics and information theory and shows that, under certain assumptions, the equations of motion for particles in a gravitational field can be recovered as entropic tendencies. According to a detailed report on this work, one of the most intriguing implications is its ability to reproduce key gravitational effects, such as planetary orbits and light deflection, from thermodynamics alone, without invoking gravity as a distinct force.
These models typically treat space as filled with microscopic degrees of freedom that carry entropy, with matter influencing the distribution of those degrees of freedom and thus the entropic forces that arise. The payoff is conceptual economy: instead of adding a new fundamental interaction, gravity becomes a manifestation of the same statistical rules that govern heat and information. Yet the bar is high. Any entropic model must match the exquisite precision of General Relativity in the solar system and in gravitational wave observations, while also addressing puzzles like dark matter and dark energy. So far, these thermodynamic constructions have shown they can mimic some classical tests, but they remain works in progress when it comes to the full cosmological and quantum picture.
How emergent gravity competes with quantum and supergravity programs
Entropic gravity does not exist in a vacuum. It competes with decades of effort to quantize gravity directly, including string theory, loop quantum gravity and supergravity. In the supergravity program, theorists extended the idea of supersymmetry to include gravity, predicting that the particle that causes gravity, the graviton, ought to have a partner. That hypothesis led to a possible explanation for the effects of dark matter and helped build a bridge between particle physics and cosmology. The architects of this framework were recognized with a major award when physicists who came up with supergravity won a 3 million dollar Breakthrough Prize, underscoring how central the search for a quantum theory of gravity has become.
From the quantum side, some theorists are exploring analogies between gravity and condensed matter systems, such as superfluids, to build unifying pictures. One proposal describes how, conversely, quantum mechanics provides a robust framework for understanding the behavior of particles and forces at microscopic scales, while General Relativity excels at describing gravity at cosmic scales, yet both struggle when it comes to describing gravity at quantum scales. In that context, a model of Conversely superfluid gravity and cyclical universe dynamics tries to unify General Relativity and quantum mechanics by treating spacetime as a kind of quantum fluid. Entropic gravity ideas sit alongside these efforts, sometimes borrowing their mathematical tools, sometimes offering an alternative narrative in which the graviton and its superpartners are not fundamental at all but emergent excitations of a deeper informational substrate.
What our universe’s shape tells us about gravity
Any claim that gravity is emergent has to confront the universe we actually observe, not just elegant equations. Cosmologists have long used Einstein’s theory of General Relativity to model the large scale structure of the cosmos, assuming that on the biggest scales the universe is homogeneous and isotropic. An Irish led study has recently questioned aspects of that picture by probing the shape of our universe and testing whether the data really support perfect isotropy. The researchers note that for more than a century, scientists have explained gravity across various scales, from our solar system to the vast expanse of the cosmos, using Einstein’s theory of general relativity, but the latest observations may hint at subtle departures from the simplest models.
For emergent gravity advocates, such cracks in the standard cosmological picture are both an opportunity and a challenge. On one hand, if the large scale universe deviates from the textbook homogeneous model, that might be easier to explain in a framework where spacetime geometry is a coarse grained description of underlying microstates rather than a rigid background. On the other hand, any entropic theory must still reproduce the successes of the current cosmological model, including the cosmic microwave background and the distribution of galaxies, while offering a better account of anomalies. The Gravity from Entropy theory, for example, explicitly targets applications in cosmology, arguing that entropy production can drive cosmic acceleration, but those claims will ultimately live or die by how well they track the detailed shape and expansion history of the real universe.
The mathematical and experimental hurdles
Even if the conceptual story of emergent gravity is appealing, the technical work of turning it into a predictive theory is formidable. Some of the most advanced approaches to quantum gravity, such as holographic dualities and Carrollian limits, involve mathematical structures that are extremely rich but also incredibly complicated. A recent case study of Carrollian holograms highlights how the mathematical structure of this theory is so intricate that extracting concrete information about our universe is challenging. Entropic gravity proposals often rely on similar holographic and thermodynamic tools, which means they inherit both the power and the opacity of these formalisms.
On the experimental side, the situation is even tougher. Many of the predicted deviations between fundamental and emergent gravity only show up at extreme scales, such as near black hole horizons or in the very early universe, which are hard to probe directly. Some tabletop experiments aim to detect tiny quantum superpositions of gravitational fields or entanglement mediated by gravity, which could hint at whether the field itself is quantum. Yet as one community discussion bluntly puts it, There is no empirical evidence to suggest that gravity is an emergent force, nor any particularly compelling experimental signature that clearly distinguishes entropic models from standard General Relativity. Until that changes, emergent gravity will remain a speculative but stimulating idea rather than an accepted pillar of physics.
How mainstream is the entropic view, really?
From the outside, it can be tempting to see every new gravity proposal as a revolution in waiting. Inside the field, the mood is more cautious. Many working physicists regard entropic gravity as an interesting perspective that sharpens our understanding of thermodynamics and information in spacetime, but not yet as a replacement for the standard framework. One recent analysis of unification efforts notes that, however intriguing, the perspective that gravity is entirely emergent from quantum information is quite speculative and not widely accepted in mainstream physics. The author stresses that, However elegant the mathematics, the lack of decisive experimental support keeps these ideas on the fringe of consensus.
That skepticism is healthy. Physics has a long history of beautiful theories that did not survive contact with data. At the same time, the entropic approach has already influenced how researchers think about black hole thermodynamics, holography and the deep links between information and geometry. Even if gravity turns out to be fundamental after all, the tools developed in emergent frameworks may still prove essential in decoding quantum spacetime. In that sense, the measure of success is not only whether entropic gravity becomes the final word, but whether it helps clarify which questions a true unified theory must answer.
Could emergent gravity help unify physics?
So does treating gravity as an entropic side effect actually bring us closer to unification, or does it simply rephrase the problem? On the optimistic reading, emergent gravity offers a way to sidestep the most stubborn clash between General Relativity and quantum mechanics by demoting the gravitational field from a fundamental player to a derived quantity. If spacetime curvature is just a macroscopic summary of microscopic quantum information, then the real task is to identify the underlying degrees of freedom and their dynamics, which would automatically be quantum. In that scenario, the unification of gravity with the other forces would come not from forcing General Relativity into a quantum mold, but from recognizing that all interactions, including gravity, emerge from a single quantum informational substrate.
The more cautious view is that entropic gravity shifts the burden without yet lightening it. Even if gravity is emergent, physicists still need a concrete microscopic model that reproduces all known gravitational phenomena and meshes with the Standard Model of particle physics. The current landscape reflects this tension. Some researchers pursue direct quantization programs like supergravity and string theory, others explore analog models such as superfluid gravity, and a third camp experiments with entropic and holographic constructions. Each path has scored partial successes and run into serious obstacles. For now, the safest statement is that emergent gravity has enriched the conversation about unification, but it has not yet delivered the decisive breakthrough that would let physicists retire Einstein’s field equations in favor of a deeper, fully quantum description.
What to watch next in the search for a unified picture
Looking ahead, the fate of entropic gravity will likely hinge on two fronts: sharper mathematics and sharper experiments. On the theoretical side, efforts like The Gravity from Entropy theory and related holographic models will need to translate their statistical mechanics foundations into clear, testable predictions, especially in cosmology and black hole physics. That means confronting detailed data on the universe’s expansion, structure formation and gravitational waves, not just reproducing Newtonian gravity in idealized setups. It also means wrestling with the same kind of intricate structures that make Carrollian holograms so hard to interpret, where the mathematical richness that promises insight also makes extracting concrete numbers about our universe challenging.
On the experimental side, the most decisive clues may come from regimes where quantum and gravitational effects are both strong: near black holes, in the early universe, or in precision quantum experiments that probe gravity at microscopic distances. As new observatories map the cosmos and laboratory tests of quantum gravity mature, any systematic deviation from General Relativity will be scrutinized through multiple lenses, including entropic ones. Until then, I see emergent gravity as a provocative working hypothesis, a reminder that what we call a “force” might sometimes be a mirage of deeper statistical laws. Whether that mirage will ultimately help unify physics, or simply sharpen our appreciation of Einstein’s legacy, remains unverified based on available sources.
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