Introduction: The Search for the Primitive
The Collapse of Geometrodynamics and the Rise of Information (1950–1980)
If Einstein established the stage, it was John Archibald Wheeler who attempted to dismantle it to find what lay beneath. Wheeler, a physicist of immense imagination who had worked with both Niels Bohr on nuclear fission and Albert Einstein on unification, spent the mid-20th century obsessed with a radical unification program known as Geometrodynamics. His intellectual journey from “Everything is Geometry” to “Everything is Information” represents the pivot point of modern physics.
The Failure of “Everything is Geometry”
Wheeler’s ambition in the 1950s and 60s was to eliminate “matter” entirely. He proposed that particles like electrons and protons were not foreign objects placed on the stage of spacetime, but were rather intense, localized knots of curvature in spacetime itself, structures he termed “geons” (gravitational electromagnetic entities). In this monistic view, there was no “It” separate from the geometry; there was only empty curved space. A charge was not a particle but a “wormhole” mouth trapping lines of force.
However, this dream of a pure geometric ontology collapsed under the weight of quantum reality. Wheeler realized that at the Planck scale ( cm), the smooth manifold of Einstein must break down into a “quantum foam,” where topology fluctuates violently, creating and destroying microscopic wormholes. Furthermore, the existence of spin-1/2 particles (fermions) proved mathematically impossible to construct purely from standard 4D geometry without introducing external structures. The “It” refused to be reduced to pure geometry.
This failure drove Wheeler toward a profound philosophical pivot. If geometry was not the bottom, what was? His interactions with his student Jacob Bekenstein regarding the thermodynamics of black holes provided the spark for a new ontology that would eventually be called “It from Bit.”
The Teacup and the Black Hole: Exploring the Entropy of the Void
In the early 1970s, Wheeler challenged his PhD student Jacob Bekenstein with a thought experiment that would ultimately destroy the concept of a classical continuum. Wheeler, alluding to the Second Law of Thermodynamics, joked about committing a “crime” by mixing hot tea with cold tea, thereby increasing the entropy of the universe without doing work. He noted that if he threw the teacup into a black hole, the entropy would seemingly vanish from the observable universe, violating the Second Law. The black hole, according to classical General Relativity, was a featureless pit; it had “no hair” (a phrase popularized by Wheeler, which his wife Janette purportedly noted showed his “naughty side”). If it had no internal features, it could have no entropy.
Bekenstein’s solution was radical: the black hole itself must possess entropy. Crucially, he proposed that this entropy was proportional not to the black hole’s volume (as one would expect for a container of gas), but to the area of its event horizon. This was derived from the realization that the area of a black hole event horizon can never decrease, mirroring the behavior of entropy.
This was the first crack in the geometric facade that would lead to the Holographic Principle. It implied that the “amount of reality” (entropy/information) a region of space could hold was bounded by its 2D surface, not its 3D volume. The “It” (the matter inside the hole) was encoded on the “Bit” (the surface area). Wheeler championed Bekenstein’s result, despite initial skepticism from Stephen Hawking (who later confirmed it via Hawking Radiation), and it led Wheeler to realize that thermodynamics and information were deeper than geometry.
“It from Bit”: The Participatory Universe (1989)
By 1989, Wheeler had fully transitioned from a “geometry-first” perspective to an “information-first” perspective. In his seminal essay “Information, Physics, Quantum: The Search for Links,” presented at the 3rd International Symposium on Foundations of Quantum Mechanics in Tokyo, he coined the aphorism “It from Bit.”
Wheeler’s thesis was a mandate for radical reconstruction. He argued that the physical world is not a pre-existing machine, but a construct built from binary choices. He drew on the philosophy of Niels Bohr, whom he considered the greatest thinker since Einstein, and the mechanism of quantum measurement to argue that: “Every it, every particle, every field of force, even the spacetime continuum itself, derives its function, its meaning, its very existence entirely, even if in some contexts indirectly, from the apparatus-elicited answers to yes-or-no questions, binary choices, bits.”
Wheeler illustrated this with a modified version of the “Game of 20 Questions.” In the classical version, an object exists (e.g., a cat), and the player asks questions to identify it. This corresponds to classical physics: reality exists independently, and we measure it. In Wheeler’s “quantum” version, there is no object chosen beforehand. The players (nature) only decide that the answers must be consistent with previous answers. If the first answer is “animal,” the second cannot be “mineral,” but the specific animal is not determined until the final question is asked. The “object” (reality) emerges only at the end of the questioning process.
This view, which he termed the Participatory Universe, posits that the observer is not a passive spectator but a co-creator of reality. The continuum of spacetime is not fundamental; it is a secondary illusion synthesized from the aggregation of billions of binary quantum events. This marked the transition from the Absolute Stage (Newton) and the Dynamic Stage (Einstein) to the Emergent Stage (Wheeler).
Wheeler pushed this logic to its extreme with the concept of “Law without Law.” He argued that just as species evolve in biology, physical laws themselves might evolve from a chaotic, lawless beginning. In the “Big Bang,” there was no geometry, no time, and no laws, only the potential for information processing. The laws of physics, in this view, are merely the “frozen habits” of the universe, stabilized over eons of quantum questioning. This radical anti-reductionism set the stage for the modern informational turn in quantum gravity.
Causal Set Theory: The Discretization of History
The most direct heir to the idea that the continuum is an illusion is Causal Set Theory (CST), championed by Raphael Sorkin and Fay Dowker. Dowker, a Professor of Theoretical Physics at Imperial College London, possesses a direct lineage to the architects of spacetime thermodynamics; she completed her PhD under Stephen Hawking in 1990. Her work represents a mathematization of Wheeler’s intuition that the “deepest bottom” is discrete.
The Rejection of the Continuum
Dowker and Sorkin argue that if one takes the “It from Bit” seriously, one must abandon the notion of continuous space at the Planck scale. General Relativity predicts its own demise through singularities, points where the curvature becomes infinite and the laws of physics break down. To Dowker, singularities are not errors but signals: they indicate that the continuum assumption is merely an approximation, much like fluid mechanics is an approximation of discrete atoms. Just as water appears smooth but is composed of discrete molecules, spacetime appears smooth but is composed of discrete “atoms” of causality.
The Core Thesis of CST:
- Discreteness: Spacetime is not infinitely divisible. It is made of discrete elements or “events.”
- Causality: The fundamental relation binding these atoms is “causal order” (Before → After).
In this framework, the universe is not a geometry but a partially ordered set (poset). The “It” is the causal link itself. A spacetime geometry is recovered only when one “sprinkles” these causal points into a manifold via a Poisson process, much like a Pointillist painting reveals an image only from a distance. This “sprinkling” is critical because it solves a major problem in discrete gravity: the violation of Lorentz invariance. A regular grid (like a chessboard) violates relativity because it has preferred directions. A random sprinkling, however, preserves Lorentz symmetry statistically, allowing the smooth manifold of Einstein to emerge from the discrete dust of causal sets.
The “Birthing of Time
Dowker utilizes the Hasse Diagram to visualize this, a graph where nodes are events and directed edges represent causal influence. The “Bit” here is the existence (1) or non-existence (0) of a causal link between two events. As Dowker notes, “The causal structure is the substance of the theory.”
This approach radically reinterprets the passage of time. In the Einsteinian “Block Universe,” all of spacetime (past, present, future) exists simultaneously; the “now” is a subjective illusion. In Causal Set Theory, the universe is a “growing set.” New atoms of spacetime are born sequentially, adhering to specific probabilistic rules known as Classical Sequential Growth (CSG) dynamics.
This model reintroduces a genuine “becoming” into physics. The universe is not a static block but a process. Dowker argues that this provides an “objective physical correlate of our perception of time passing.” The “now” is the active edge of the causal set where new events are being birthed. Consciousness, in Dowker’s view, is the “internal view” of this objective birth process. What we experience as the flow of time is the accretion of new causal atoms onto the existing history of the universe. Here, the “bit” is the birth of a new event, a digital tick of the cosmic clock that expands the universe one atom at a time.
Relational Quantum Mechanics & LQG: The Disappearance of Time
While Dowker seeks to discretize the spacetime container to save the “flow” of time, Carlo Rovelli, a founder of Loop Quantum Gravity (LQG), seeks to dissolve the “container” entirely and argues that time itself is the illusion. Rovelli’s work is a synthesis of Wheeler’s insistence on the observer and the non-perturbative quantization of gravity.
Relational Quantum Mechanics (RQM)
Rovelli introduced Relational Quantum Mechanics in 1994, derived from the realization that quantum mechanics acts much like special relativity. In relativity, velocity is not a property of an object; an object has velocity only relative to an observer. Rovelli extends this to all physical states: an electron does not have a “position” or a “spin” in the abstract. It has a state only relative to a specific physical system interacting with it.
“The universe is not just simply the position of all its Democritean atoms. It is also the net of information systems have about other systems.” In this view, there is no “View from Nowhere” or “God’s Eye View” of the universe. There are only localized, relative descriptions.
The Relational “Bit”:
- Bit: An interaction between two systems (a “measurement”).
- It: The resulting correlation established between them.
This framework resolves the paradoxes of quantum mechanics (like Schrödinger’s Cat) by acknowledging that for one observer (inside the box), the cat is definite, while for another (outside), it remains entangled. There is no contradiction because there is no single, absolute “state of the universe.”
Loop Quantum Gravity and Spin Networks
When applied to gravity, this relational perspective leads to Loop Quantum Gravity. In LQG, the continuous metric of Einstein is replaced by Spin Networks, graphs of adjacency where nodes represent chunks of volume and links represent surfaces of area.
Crucially, these areas and volumes are quantized. Just as an electron can only have specific energy levels, space itself can only exist in discrete “packets” of volume ( cm³). These networks do not exist in space; they are space. A “spin foam” describes the evolution of these networks.
The Thermal Time Hypothesis
Perhaps the most radical consequence of Rovelli’s work is the Thermal Time Hypothesis. In the fundamental equations of LQG (the Wheeler-DeWitt equation), the variable (time) disappears entirely. The theory describes how physical variables change with respect to one another (e.g., how the position of a pendulum changes with respect to the position of a clock hand), but there is no external “time” governing the whole.
If time is not fundamental, why do we experience it? Rovelli argues that time is a macroscopic, statistical phenomenon, akin to “heat.” Just as “temperature” is not a property of a single molecule but an average of billions, “time” emerges only when we statistically average over the microscopic informational states we cannot track. Time is the expression of our ignorance. In a universe of perfect information, there would be no time, only a frozen network of relations. This aligns perfectly with the “It from Bit” ethos: the macroscopic world of “It” (time, heat, flow) is a blurred approximation of the microscopic “Bits” (relations).
Holography and “It from Qubit”: The Unification
The third and perhaps most dominant modern path fuses Wheeler’s information theory with High Energy Physics and String Theory. This movement, often unified under the slogan “It from Qubit,” posits that spacetime is a hologram. This field is led by figures like Juan Maldacena at the Institute for Advanced Study, Leonard Susskind at Stanford, and the researchers of the Simons Collaboration on “It from Qubit.”
The AdS/CFT Correspondence
In 1997, Juan Maldacena made a discovery that shook the foundations of physics: the AdS/CFT correspondence. He showed that a theory of quantum gravity (String Theory) in a bulk, saddle-shaped 3D space (Anti-de Sitter space or AdS) is mathematically equivalent to a quantum field theory (Conformal Field Theory or CFT) living on its 2D boundary.
This was the mathematical realization of the Holographic Principle hinted at by Bekenstein’s black hole entropy. It implies that everything happening inside the universe (gravity, stars, black holes) is a “hologram” projected from the interactions of particles on the boundary of the universe. The “It” (the 3D bulk) is generated by the “Bit” (the 2D boundary data).
Entanglement Builds Geometry
While Wheeler spoke of classical “bits” (Yes/No), Maldacena and his colleagues realized that the glue holding spacetime together is Quantum Entanglement. The slogan was explicitly updated from “It from Bit” to “It from Qubit” to reflect this quantum nature.
The connection between entanglement and geometry was solidified by the Ryu-Takayanagi formula, which relates the entanglement entropy of a region on the boundary to the area of a minimal surface dipping into the bulk spacetime. This suggests that the “area” of space is literally a measure of the entanglement between quantum fields.
ER=EPR: The Wormhole Connection
The most startling insight in this domain is the ER=EPR conjecture, proposed by Maldacena and Leonard Susskind in 2013. This conjecture links two concepts proposed by Einstein in 1935 which were thought to be unrelated:
- ER: The Einstein-Rosen bridge (a wormhole connecting two regions of spacetime).
- EPR: The Einstein-Podolsky-Rosen pair (two particles connected by quantum entanglement).
Maldacena and Susskind proposed that these are the same thing. Entanglement is a wormhole. A single pair of entangled particles is connected by a Planck-scale wormhole. If you entangle two black holes, they are connected by a large, geometric wormhole.
This resolves the Black Hole Firewall Paradox. The paradox suggests that if black hole evaporation preserves information (unitary quantum mechanics) and the event horizon is smooth (General Relativity), a contradiction arises regarding the entanglement of particles. ER=EPR resolves this by identifying the “inside” of the black hole with the entanglement radiation on the “outside.” The geometry of the interior is built out of the entanglement with the exterior.
This view suggests that the smooth connectivity of spacetime is an emergent property arising from the entanglement of quantum bits. If one were to break the entanglement (the “qubits”) between two regions of space, the space between them would literally pinch off and separate. Spacetime is not the stage; it is the result of the information processing of the boundary qubits.
Analysis: The Nature of the “Bit”
To fully grasp the magnitude of this revolution, one must compare how these distinct frameworks define the fundamental informational unit, the “Bit,” that builds the “It.” The divergence in their mathematical approaches disguises a striking convergence in their ontological conclusions.
┌──────────────────────────────────────────────────────────────────────┐
│ WHAT IS THE "BIT" OF REALITY? │
└──────────────────────────────────────────────────────────────────────┘
1. THE CAUSAL BIT (Sorkin/Dowker)
The Universe is a growing order.
BIT = A directed link (A causes B).
[ A ] ───> [ B ]
2. THE RELATIONAL BIT (Rovelli)
The Universe is a correlation.
BIT = Interaction between Systems.
[System 1] <~~~ (Correlation) ~~~> [System 2]
3. THE HOLOGRAPHIC BIT (Maldacena/Susskind)
The Universe is a projection.
BIT = Entanglement on the boundary (Qubit).
Boundary: 01101 ---> Bulk Geometry: (Spacetime)
4. THE PARTICIPATORY BIT (Wheeler)
The Universe is a question.
BIT = The Answer (Yes/No).
Observer (?) ───> [Nature] ───> "Yes"
The Shift from “Law” to “Code”
A subtle but profound trend visible across these theories is the shift from physics as “Law” (binding differential equations acting on a continuum) to physics as “Code” (algorithmic rules acting on discrete data).
In the Newtonian and Einsteinian paradigms, the universe was governed by differential equations. These equations assume a continuum; you can zoom in infinitely and the laws still hold. But in the “It from Bit” and “It from Qubit” paradigms, the laws are akin to cellular automata or logical gates.
Hilbert’s Dream Revisited: In 1900, Hilbert wished to axiomatize physics. While his specific continuum-based axioms were superseded, the spirit of his program has returned with a vengeance. Causal Set Theory and “It from Qubit” essentially attempt to find the “machine code” of the universe. The Bekenstein Bound () acts as a constraint on the memory capacity of the universe, much like a hard drive limit. This implies the universe has a finite computational capacity.
╔══════════════════════════════════════════════════════════════════════╗
║ SYSTEM UPDATE: ONTOLOGICAL KERNEL CHANGE ║
╠══════════════════╦════════════════════════╦══════════════════════════╣
║ PARAMETER ║ VERSION 1.0 (Physics) ║ VERSION 2.0 (Info) ║
╠══════════════════╬════════════════════════╬══════════════════════════╣
║ PRIMITIVE UNIT ║ Point Mass / Particle ║ Qubit / Causal Link ║
║ ║ (Hard "Stuff") ║ (Pure Logic) ║
╠══════════════════╬════════════════════════╬══════════════════════════╣
║ OPERATING SYSTEM ║ Continuum (R⁴) ║ Discrete Graph (G) ║
║ ║ (Smooth Manifold) ║ (Network/Lattice) ║
╠══════════════════╬════════════════════════╬══════════════════════════╣
║ DYNAMICS ║ Differential Equations ║ Algorithms / Rules ║
║ ║ (∂x/∂t) ║ (If A then B) ║
╠══════════════════╬════════════════════════╬══════════════════════════╣
║ TIME ║ External Dimension t ║ Internal Update Step ║
║ ║ (The "Block") ║ (The "Tick") ║
╠══════════════════╬════════════════════════╬══════════════════════════╣
║ PERSPECTIVE ║ "View from Nowhere" ║ Relational / Internal ║
║ ║ (God's Eye) ║ (The User/Observer) ║
╚══════════════════╩════════════════════════╩══════════════════════════╝
The End of the “View from Nowhere”
Classical physics assumed an objective state of the world that existed independent of observation, a “God’s eye view.” Wheeler, Rovelli, and Dowker all dismantle this.
In Causal Sets, the “growth” of the universe happens, but there is no external time parameter to track it. The process is internal.
In Relational QM, there is no “state of the universe,” only states relative to specific subsystems.
In Holography, the description of the universe depends on where you place the boundary.
The “Bit” is always perspectival. Information is not a thing that exists in the void; it is a measure of correlation between two entities. The dematerialization of the “It” brings with it the realization that reality is fundamentally relational.
Wheeler’s “It from Bit”, Bekenstein–Hawking horizon entropy, causal set theory (Sorkin–Dowker), relational quantum mechanics (Rovelli), and holography (Maldacena–Susskind) converge on a single conclusion: geometry, time, and matter are emergent from a more primitive informational substrate composed of relational quanta (causal links, entanglement, qubits).
The Eternal Recurrence of the “It” and the Second Revolution
The quest for the fundamental constituent of reality has followed a cyclical pattern across millennia. Two archetypal models repeatedly contend: the discrete, which posits indivisible units moving through a void (Democritus’s atoms, Kaṇāda’s paramāṇu, Ashʿarite time-atoms, Newton’s corpuscles), and the continuous, which envisions an unbroken plenum of connection and resonance (Anaximander’s apeiron, Stoic pneuma, Chinese qi, Descartes’s vortices). Newton appeared to crown the discrete view with his hard, inert particles set against absolute emptiness. Yet history proved otherwise. Concepts once marginal, Kaṇāda’s unseen forces (adṛṣṭa), Chinese resonance (gǎnyìng), and Mohist relational time, re-emerged as electromagnetic fields, quantum entanglement, and relativistic spacetime.
By 1905 the classical “It” had already dissolved. Newton’s solid mass gave way to Leibniz’s perceiving monads, Maupertuis’s teleological Action became Hamilton’s abstract variational principle, heat and motion fused into Boltzmann’s statistical ensembles, and action-at-a-distance yielded to Faraday-Maxwell fields. The ether crisis exposed the final contradiction: a mechanical universe could no longer rest on an absolute, rigid stage. Matter was no longer a thing but a ripple, a probability, a curvature.
Einstein and Minkowski fused space and time into a dynamic continuum, making the stage itself an actor. For half a century geometry seemed ultimate. Yet Wheeler’s mid-century program revealed that even curved spacetime collapses at Planck scales into quantum foam. The true revolution, the second after relativity, was the recognition that geometry is emergent. Contemporary approaches converge on this insight:
- Causal Set Theory (Dowker) replaces the continuum with a discrete partial order of events, from which spacetime approximates.
- Loop Quantum Gravity (Rovelli) derives geometry from relational spin networks; time dissolves into thermal perspective.
- Holographic duality (Maldacena) projects bulk spacetime from entanglement on a lower-dimensional boundary.
In each case the fundamental entities are not material points or geometric manifolds but causal links, relational quanta, and qubits. The universe is not a machine governed by prior laws. It is a participatory information-processing system. As Wheeler declared, physical reality arises from the answers to yes/no questions posed by observers embedded within the system itself.
The “It” has returned to its ancient discrete roots, yet transformed. The atom is now the bit, the causal connection, the entangled correlation. The void is not empty. It is pregnant with potential observations. What began with Thales’ water and Democritus’s atoms has culminated in the realization that the world is made neither of stuff nor of seamless fabric, but of information, the ultimate, self-referential substrate from which both continuity and discreteness emerge.
Starting from the premise that information is a fundamental constituent of reality, the first and most crucial question is: What is the simplest possible “bit” of reality and the simplest process of “participancy” from which a universe could emerge? We conclude that a single point is structurally sterile, lacking the relational potential for evolution. A single qubit is pure potential, a description of what could be, not what is. Its measurement outcome in a given basis is random, incapable of predicting anything beyond its own statistics. For a measurement to be meaningful, a relationship must already exist.
The Logical Operations of Reality
The historical trajectory from substance to field to information leaves us with a universe composed of bits, qubits, or causal sets. Yet, a fundamental problem persists: data without a processor is static. A "bit" is merely a state; it does not explain its own evolution or its own persistence.
To move from a description of states to a theory of dynamics, we must look to the logical operators that govern the relationship between pieces of information. If reality is fundamentally informational, its behaviors must derive from the two primary relationships available to any logical system: distinction and equivalence.
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Inequality () is the Engine of Time. For a universe to be dynamic, the current state must be distinguishable from the next. The condition establishes a gradient, a difference in information potential. This inequality is the fundamental requirement for any transition to occur. It differentiates cause from effect and provides the "imperative" for the system to update. Without inequality, there is no sequence, only a static singularity.
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Equality () is the Architecture of Space. For a universe to contain objects, it must possess stability. The condition establishes a state of equilibrium where the drive for transition ceases or cycles. This equality is the fundamental requirement for structure to emerge. It creates a "solution" to the informational flux, allowing a pattern to persist against the flow of change. Without equality, there is no durability, only fleeting noise.
These two conditions, the logical drive to differentiate and the constraint to balance, provide the minimal framework required to construct a universe that both flows and endures. As we move to formal construction, we shall see that the drive of Inequality physically manifests as the Causal Link, while the constraint of Equality stabilizes as the Closed Cycle.
From Potential to Prediction
A prediction is a statement of correlation. It is the ability to measure a property here and, based on that outcome, infer a property over there. This requires a system of at least two parts whose states are correlated. The minimal structure that contains such relational information is not a point or a qubit, but a causal connection.
We therefore posit that the most primitive element of reality is the directed edge, or causal link, denoted . This is not a statement about objects and . Instead, it describes the pure, directed relation of causal influence itself: the indivisible, pre-geometric atom of temporal order, “before implies after.”
While vertices (points, events) and edges (connections, relations) may be the simplest conceptual pieces of information, they are pre-geometric. Therefore, we propose a novel axiom: Relational cycles (loops) are the fundamental quanta of geometric information. This line of reasoning leads us to propose a foundation for the theory of Quantum Braid Dynamics, stated in two parts:
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The Primitive of Causality: The fundamental entity of the universe is the directed causal link, denoted . This is the irreducible atom of causal order.
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The Primitive of Geometry: The simplest, stable structure that can be built from these links, and the fundamental quantum of geometric information is the closed 3-cycle, . This self-referential loop provides the first stable standard against which metric intervals can be quantified and structure can be measured.
From matter to motion, we now stand at the threshold where philosophical speculation must yield to formal construction. The task ahead is to translate these conceptual primitives into a precise deductive system capable of generating dynamics, geometry, and ultimately cosmology using only the minimal assumptions required for a self-consistent universe to build itself from relational information alone.