There is a distinction that appears everywhere in physics.
Something can happen.
And something does happen.
A particle can be detected in one place rather than another.
A photon can be absorbed rather than transmitted.
A radioactive atom can decay rather than remain in its previous state.
A physical system has possibilities.
Then, somehow, one possibility becomes actual.
Quantum theory gives us extraordinarily precise ways of calculating these possibilities.
What it does not make conceptually easy is the transition between them.
What is it for a potential to become actual?
This question is usually approached through the language of measurement, observation, collapse, decoherence, branching or probability.
But our relational ontology suggests that we should step back from those particular interpretations.
Before asking what causes a wavefunction to collapse, we should ask a more basic question:
What is an actualisation?
Potential is not actuality
We began this investigation by distinguishing the wavefunction from the particle.
The distinction is simple but profound.
The wavefunction represents potential structure.
A particle is an actual instance.
The wavefunction is therefore not a cloud of particles waiting to be discovered.
It is a structured description of what can be instantiated.
The distinction is analogous to the relationship between climate and weather.
Climate does not contain little weather events.
It describes a structured space of possible weather patterns.
A particular storm is an actual event.
Likewise, the wavefunction does not contain little particles distributed among possible locations.
It describes structured possibilities for actual physical events.
This gives us two distinct ontological categories:
potential
and
actuality.
The difficulty begins when we ask how one becomes the other.
The temptation to make potential into a thing
There is a familiar temptation in thinking about quantum theory.
We imagine the wavefunction as some kind of physical object.
The particle is then imagined as something contained within it, waiting to become visible.
But this picture creates unnecessary problems.
If the wavefunction is a physical thing, what kind of thing is it?
Where is it?
Does it exist in ordinary space?
If not, what kind of space does it occupy?
And when a particle is detected, what exactly has happened to the wavefunction?
These questions become difficult because the ontology has already gone wrong.
The wavefunction need not be a thing.
It can instead be understood as potential structure.
The question then changes.
We no longer need to ask how a strange physical substance turns into a particle.
We need to ask how a possibility becomes instantiated.
That is a different problem.
Instantiation
The word instantiation is useful because it avoids some of the baggage surrounding “collapse”.
Consider language.
A language contains a structured field of potential expressions.
An actual utterance instantiates one of those possibilities.
The utterance is not identical to the language.
Nor is the language a physical object from which the utterance is extracted.
The utterance is an actual realisation of a potential structure.
This is close to what we mean when we say that a particle is an instance of the potential represented by the wavefunction.
The analogy should not be pushed too far.
But it gives us a useful conceptual distinction.
The potential does not become actual by transforming into a second substance.
It becomes actual through instantiation.
That suggests that actualisation is not an additional physical object.
It is a relation between potential structure and an actual event.
But what instantiates what?
The next question is unavoidable.
A linguistic expression is instantiated by an actual speaker in an actual context.
What instantiates a quantum possibility?
We cannot simply say:
“The wavefunction instantiates itself.”
That would turn potential into an agent.
Nor can we say:
“An observer instantiates it.”
That would make consciousness fundamental to physical actualisation, which is not required by the ontology.
Something physical happens.
A system interacts with another system.
An event occurs.
A detector registers something.
A particle is absorbed.
A field changes.
The world acquires a determinate state of affairs.
Actualisation therefore occurs within physical relations.
This is the first important step.
Potential does not become actual in isolation.
It becomes actual through interaction.
Actuality is relational
Suppose an electron is detected.
What has actually happened?
It is tempting to say:
“The electron was really there all along, and the detector discovered it.”
But that is not what quantum theory straightforwardly tells us.
The physical event is an interaction.
The detector acquires a particular state.
The electron participates in that interaction.
The result is a determinate correlation between physical systems.
There is now something that was not there before:
an actual relation.
The detector is in one state rather than another.
The electron has participated in one interaction rather than another.
The surrounding physical system has correspondingly changed.
Actuality is therefore not merely a property of an isolated object.
It is established through a physical event.
The event matters
This gives us a different conception of an event.
An event is not simply something that happens at a point in spacetime.
If spacetime is emergent, that definition would already assume what we are trying to explain.
Instead, an event can be understood more fundamentally as:
an actualised physical differentiation within a relational process.
Before the event, several possibilities may be available.
After the event, one particular outcome has been instantiated.
The world has acquired a distinction.
Something is now the case that was not previously the case.
This is what makes actuality ontologically significant.
Actuality is not merely probability equal to one.
It is the emergence of a determinate physical relation.
Probability is not actuality
This distinction is especially important.
Suppose quantum theory assigns probabilities to possible outcomes.
We might say:
outcome A has probability 0.6;
outcome B has probability 0.4.
Neither outcome is yet actual.
The probabilities describe potential.
Then an interaction occurs.
Suppose A is instantiated.
The physical world now contains an actual relation corresponding to A.
Probability has not “turned into” actuality in the sense that a substance has changed form.
Rather, a possibility has been selected through physical actualisation.
The distinction resembles the difference between a set of possible moves in a chess position and the move that is actually made.
The possible moves are real possibilities.
But only one becomes part of the actual history.
The move does not exist somewhere inside the game beforehand.
It becomes actual when the move is made.
The analogy is imperfect, but the ontological distinction is useful.
What determines the actualisation?
Now we encounter one of the deepest questions in quantum theory.
If several possibilities are available, why does one actualise rather than another?
The standard answer is expressed probabilistically.
The theory tells us the probability distribution.
But the probability distribution does not itself explain why this particular event occurred.
This is not necessarily a defect.
A theory can predict statistical structure without predicting individual events.
But philosophically, the question remains.
What is the relation between:
the space of possible outcomes
and
the actual outcome that occurs?
Our relational ontology suggests that we should not expect the answer to be a hidden variable belonging to the particle.
The actualisation may depend upon the entire relational context in which the event occurs.
The outcome is not necessarily determined by an intrinsic property carried by an isolated object.
It may be an event produced within a network of constraints and affordances.
Context matters
This is one of the deepest lessons available from quantum theory.
The possible outcomes of a measurement depend upon the physical arrangement of the measurement.
Change the experimental context and the possible distinctions that can be actualised change.
This does not mean that reality is subjective.
The context is physical.
A measurement apparatus is a physical system.
Its orientation, state, coupling and interaction with the system are all physical conditions.
Thus the actualisation is not:
a private choice made by the particle.
Nor is it:
a decision made by the observer.
It is an event within a physical relational configuration.
The possibilities are structured by the system.
The actualisation occurs through the interaction.
Potential is constrained
This gives us a useful way to think about the wavefunction.
The wavefunction is not simply a list of possibilities.
It is a structured field of possibilities constrained by the physical situation.
The system cannot actualise arbitrarily.
Some outcomes are possible.
Some are impossible.
Some are more probable.
Some are related by symmetries.
Some are excluded by conservation laws.
Potential is therefore not unlimited freedom.
It is structured possibility.
This distinction will become crucial later.
Because if actualisation changes the relational situation, then it also changes the field of subsequent possibilities.
The universe is not merely selecting from a fixed menu.
Each actualisation changes the conditions under which future possibilities exist.
Actualisation changes the world
Suppose a particle is detected.
The detector has changed.
The particle has changed state.
The environment has changed.
Information has been established.
The set of possible future interactions has changed.
The actual event therefore does not merely record what happened.
It modifies the relational structure of what can happen next.
This is perhaps the most important feature of actualisation.
An actual event is generative.
It closes some possibilities and opens others.
The event becomes part of the conditions for subsequent events.
We therefore have a dynamic sequence:
potential
↓
actualisation
↓
new relational situation
↓
new potential
↓
further actualisation
The ontology is beginning to look less like a collection of things and more like a process.
The universe as becoming
This suggests a different way of thinking about physical reality.
The universe is not merely a set of things that exist.
It is a succession of actualisations through which new relational structures become established.
At every moment—not necessarily in the ordinary temporal sense—there are possibilities.
Some become actual.
Their actualisation changes the situation.
The changed situation generates new possibilities.
And so the process continues.
This gives us a very simple grammar:
possibility → actualisation → consequence → new possibility.
Perhaps this is closer to the underlying logic of physical reality than:
thing → property → interaction.
The latter treats becoming as something that happens to already existing things.
The former treats becoming as constitutive of the things themselves.
Where are the things?
If this is right, we can now ask a slightly mischievous question.
Where are the objects?
If a particle is a stable pattern of actualised relations, then the particle is not something that exists independently of its history.
Its identity is expressed through the regularity of its possible interactions.
Likewise, a macroscopic object is an extraordinarily stable pattern of physical processes.
We ordinarily treat it as a thing because its pattern persists.
But ontologically, its persistence may be the result of continual actualisation.
The table remains the table because an enormous number of physical relations continue to reproduce a stable pattern.
The stability is real.
The underlying processes are dynamic.
This is not a contradiction.
It is what emergence means.
Actuality is selective
There is another important feature of actualisation.
Actuality is selective.
From among possible states, one determinate state becomes actual.
This does not necessarily require a mysterious act of selection by an external agent.
It means simply that reality has determinate events.
The physical world is not exhausted by a catalogue of possibilities.
There is a difference between:
what could happen
and
what happened.
Quantum theory describes the structure of the former extraordinarily well.
The ontology must also account for the latter.
This is why the distinction between potential and actual cannot be treated as merely linguistic.
It is built into the physical character of the world.
The classical world as accumulated actuality
Perhaps this also helps explain why the everyday world appears so definite.
At the microscopic level, physical systems possess rich fields of potential.
But actualisations accumulate.
Each event leaves physical traces.
Those traces participate in subsequent interactions.
Macroscopic systems therefore contain enormous histories of actualised relations.
The result is a world in which possibilities are strongly constrained by what has already happened.
The chair is here.
The Earth is here.
The detector has recorded this result.
The star has emitted these photons.
The universe has this history rather than another.
The apparent solidity of classical reality may therefore arise not because quantum potential disappears, but because actuality has accumulated into stable relational structures.
The classical world is the world of persistent actualised patterns.
Decoherence, without reification
This gives us a possible way to reinterpret decoherence.
Decoherence is often described as the process through which quantum superpositions become effectively classical through interaction with the environment.
We need not dispute the mathematics.
But ontologically, we can describe the process differently.
Interaction creates correlations.
Those correlations become distributed through the environment.
Certain distinctions become robust.
Alternative possibilities cease to interfere in ways that are accessible to the macroscopic system.
The result is an effectively stable classical pattern.
Nothing mysterious needs to happen to a physical substance called “the wavefunction”.
The relational structure of the physical system has changed.
The environment has become correlated with particular alternatives.
Actuality becomes increasingly robust.
This is exactly what we would expect if classical reality is a stable organisation of actualised relations.
The arrow of becoming
There is an interesting consequence.
If actualisation changes the space of future possibilities, then there is an asymmetry between what has happened and what can happen.
The past contains actualised events.
The future contains possibilities.
The present is where potential becomes actual.
This does not mean that fundamental physics must contain an absolute flowing time.
It means something more modest and perhaps more fundamental:
actuality and potential are not interchangeable categories.
A past event is actual.
A future event is potential.
The distinction does not require a metaphysical river of time.
It requires only that physical history accumulates through actualisation.
This may eventually help us understand why a temporal order appears so naturally in a universe whose deepest description may not contain time as a fundamental substance.
But that is a question for another stage of the investigation.
Actualisation and information
Our earlier investigation of information now returns.
An actualisation creates a distinction.
Before the event, several outcomes may have been possible.
After the event, one has occurred.
The physical situation therefore contains a new distinction.
That distinction can become correlated with other physical systems.
A detector records it.
A memory stores it.
The environment carries traces of it.
Information, in this sense, is generated through actual relational differences.
This is why information is not a substance that must be carried around somewhere.
It is a structure in the relations among physical states.
Actualisation produces such structure.
The universe continually accumulates distinctions.
That is one way of understanding physical history.
The black hole looks different again
This perspective also casts our black-hole investigation in a new light.
The information problem seemed to ask:
Where does information go when matter falls into a black hole?
But if information is relational structure produced through actualisation, then the question becomes:
How are the distinctions established by actual events transformed as the relational structure of the system changes?
That is a much more subtle question.
Information does not need to be a substance travelling through spacetime.
It is embodied in correlations.
As the physical relations change, those correlations can be redistributed.
The problem is therefore not simply whether information “remains inside” or “comes back out”.
We need to understand how actualised distinctions persist, transform and become correlated across changing physical structures.
That is precisely the kind of question a relational ontology is equipped to ask.
Actuality is not a second layer of reality
At this point we should guard against another mistake.
It might sound as though we have two worlds:
the world of potential
and
the world of actuality.
But there are not two worlds.
There is one physical process.
Potential describes what can be actualised.
Actuality is the instantiation of some of those possibilities.
The two are related aspects of one evolving relational structure.
The wavefunction does not exist in one universe while particles exist in another.
The wavefunction describes the potential structure of the physical process.
Particles and events are actualisations within that process.
The distinction is ontological, not spatial.
The mystery of selection
Nevertheless, a genuine mystery remains.
If several actualisations are possible, what determines which one occurs?
We must resist the temptation to answer too quickly.
Perhaps the answer is irreducibly probabilistic.
Perhaps deeper structure determines the probabilities but not individual outcomes.
Perhaps what we call an individual outcome is itself emergent from a deeper relational process.
Perhaps the question of “which possibility?” is not meaningful until the physical context has completed the relevant interaction.
We do not yet know.
And we do not need to pretend that relational ontology solves the measurement problem merely by renaming it.
What it does is relocate the problem.
Instead of asking how a physical wave-like substance collapses into a particle-like substance, we ask:
How does a structured field of physical potential become instantiated as a determinate relational event?
That is a cleaner question.
It may also be a more tractable one.
From event to relation
Now something important happens to our larger investigation.
An actualisation is not the end of the story.
Once an event occurs, it stands in relations to other events.
The actual event can influence subsequent possibilities.
It can become correlated with other systems.
It can leave traces.
Repeated actualisations can produce stable patterns.
And stable relational patterns may eventually become describable geometrically.
We therefore have the beginning of the sequence anticipated at the end of the previous essay:
potential
↓
instantiation
↓
actual event
↓
relation
↓
stable pattern
↓
geometry
The first transition is what we have examined here.
The later transitions remain to be understood.
And now we can finally see why geometry should not have been our starting point.
Before asking how geometry emerges, we needed to understand what it could emerge from.
The fundamental process
If our interpretation is correct, the fundamental physical process may therefore be neither:
objects moving through spacetime
nor:
spacetime fluctuating quantum mechanically.
It may instead be something like:
structured potential becoming actual through relational interaction, with actualisations generating new relational possibilities.
That is a process ontology.
It does not deny objects.
It explains them as persistent patterns.
It does not deny spacetime.
It explains it as an emergent relational structure.
It does not deny quantum theory.
It takes its distinction between potential and actual seriously.
And it does not deny general relativity.
It asks how its geometry might arise from the accumulated organisation of actual events.
We have therefore not replaced physics with metaphysics.
We have changed the ontological question that physics is being asked to answer.
The next question
We began with the question:
How does a potential become an actual?
Our answer has been tentative but significant.
An actualisation is not the transformation of one physical thing into another.
It is the instantiation of potential within a physical relational context.
The actual event establishes a determinate distinction.
That distinction changes the relational situation.
The changed situation generates new possibilities.
Thus:
potential becomes actual, and actuality becomes the condition of further potential.
This gives physical becoming a direction without requiring a fundamental flowing substance called time.
But now the next question is unavoidable.
If actual events establish relations, and if relations can persist and organise into stable patterns, then perhaps something remarkable happens at sufficiently large scales.
Those patterns may become measurable.
They may acquire regularity.
They may exhibit dimensional structure.
They may support invariant intervals.
They may form causal order.
In other words, they may begin to look like geometry.
So now, and only now, we are ready to ask the question that we postponed earlier:
Where does geometry come from?
Perhaps geometry is not the arena in which physical becoming takes place.
Perhaps geometry is what physical becoming leaves behind when its relations become stable enough to be described as a world.
🍷🙂
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