Quantum Theory: A Second Way to Relativize Realism beyond Structuralism

On the Possible Coexistence of Realism, Structuralism, and Quantum Theory

Quantum Theory: A Second Way to Relativize Realism beyond Structuralism

On the Possible Coexistence of Realism, Structuralism, and Quantum Theory

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1. Non-realist views are possible even without structuralism

One of the basic frameworks of contemporary philosophy can be sketched, roughly, as a tension between

• Realism, and
• Structuralism.

Realism is the default setting that has soaked into almost everyone’s mind:

There are solid “things” and “essences” in the world, existing independently of our minds.
Observation and language simply pick them up and label them.

Structuralism responds to this by saying, in effect:

No, what comes first is “structure,” “difference,” and “institution.”
“Objects” and “subjects” arise on the side of what is structured.

In that sense, structuralism has functioned as a way to relativize the absolute claims of realism.

What I want to say first is this:

• Realism is extremely useful. It develops more or less naturally in ontogeny as a “cognitive OS” that works in daily life.
• Structuralism is an “OS upgrade” that lets us meta-recognize and partially rewrite that realist OS.

However, structuralism is not the only position that both criticizes realism and offers a coherent alternative picture of the world.

There is another very powerful candidate: quantum theory (quantum mechanics, quantum field theory, and the quantum world-view more broadly).

Whether or not we want to call quantum theory a “philosophy,”
its world-picture is philosophically explosive enough that we might as well treat it as one.

For many of us living now, who feel that

• realism alone is not enough, but
• living solely inside structuralism is a bit too cumbersome, verbose, and tiring,

quantum theory can serve as a third stance that sits nicely alongside realism and structuralism.

My personal stance could be summarized like this:

• At the level of basic epistemology and ontology, structuralism can include realism,
  whereas realism cannot fully include structuralism. In that sense, structuralism is more encompassing.
• At the same time, realism still works surprisingly well; it remains convenient in everyday life and in engineering.
• If we then introduce quantum theory as a third pole from the side of physics,
  we can put realism and structuralism under pressure from both the “humanities” and the “natural sciences.”

This three-cornered configuration is, I think, the richest and most productive.

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2. “Boundary” and “volume” as the core of realism

At the core of realism lies something like Descartes’ notion of extension.

In the material world, things have volume, boundaries, and occupy space.
They do not simply pop into or out of existence, and we expect a certain degree of persistence.

This image underwrites our naïve sense of “substance” or “reality.”

Mind and ideas may look different from this, yet we often treat them metaphorically as if they were little physical objects:

• Thoughts feel like they are “in the head,”
• Feelings often feel like they are “sitting in the chest.”

In many cases, we are borrowing the metaphors of extension and volume from the physical world to grasp mental phenomena.

However, when we try to treat “extension” seriously in mathematics, we run into trouble quite early on.
Already in Euclidean geometry, we are told:

A point is that which has no size.

If you’re satisfied with this, that’s fine; but if you think about it carefully, it is a very strange definition.

• How can “points” with no boundary and no volume serve as the basis of lines, planes, and solids?
• If we straightforwardly extend our realist intuition of “things,” the concept starts to slip.

This kind of unease and limit is part of what led, through set theory and topological spaces,
to structuralist modern mathematics (category theory and beyond).

Even so, in practice we still treat “points” and “mass points” in a realist fashion, because that is simply more convenient.

Even in quantum theory,

• if you push too hard on questions about the exact size and boundary of a particle, your head explodes;
• so we partially give up, and treat it as if it were “a tiny object here,” a sort of pragmatic fiction.

In that sense, we cannot completely abandon the borrowed tools of realism even in quantum theory.

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3. Classical physics is thoroughly realist

In this sense, classical physics is almost purely a realist world.

• Mass points
• Rigid bodies
• Continua such as fluids and elastic media

All of these can be learned with realist intuitions alone.

“At such-and-such a place there is an object with such-and-such mass,
and its position and velocity are always well defined.”

Observation is simply the act of reading off properties that are already there,
and time evolution is given by Newton’s equations and the like.

This is, philosophically, a combination of naïve realism + determinism.

The flip side is that

• if your world consists only of realism + classical physics,
• and you then try to tackle quantum theory, you will almost certainly run into a wall.

Trying to understand quantum theory solely as an extension of high-school physics leaves you fatally under-equipped.

If, by contrast, you have already internalized

• structuralism (as a relativization of meaning, language, and institution), and
• quantum theory (as a relativization from the side of physics),

then looking back on classical physics becomes a luxury.

• Assumptions that once felt “obvious” suddenly show their seams.
• You begin to enjoy re-examining your former fixed ideas.

But of course, acquiring those newer perspectives in the first place comes with a high learning cost.
Both structuralism and quantum theory are “expensive” to learn.

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4. Contemporary philosophy’s three basic positions:

Realism, structuralism, and quantum theory

With the arrival of structuralism and post-structuralism, contemporary philosophy

• relativized realism,
• meta-recognized that very process of relativization, and
• learned to play with multiple perspectives.

Buddhism makes this structure quite explicit:

• Early Buddhism’s dependent origination and middle way,
• Mahāyāna’s doctrine of emptiness and the Madhyamaka,
• Tiantai’s threefold truth (the provisional, emptiness, and the middle).

If we make a rough correspondence with our current topic, we might say:

• Provisional truth (仮諦)
  • The everyday world of “taking things as they appear.”
  • Naïve realism, socially constructed fictions.
• Emptiness (空諦)
  • Denial of substance, and seeing at the level of relations and conditions.
  • Structuralist and post-structuralist relativization.
• Middle truth (中諦)
  • A meta-stance that passes through both while preserving each.
  • A way of switching between multiple OSs as needed.

Against this background, the question arises:

Besides structuralism, are there other theories that can stand as counter-positions to realism?

If we look only within contemporary philosophy,
it is somewhat difficult to produce concrete examples.

Here, quantum theory becomes a very attractive candidate.

Quantum theory has the curious property that

• if we want, we can translate it into the language of structuralism;
• with some effort, we can also give it realist reinterpretations;

yet at the same time,

• it is grounded in empirical science,
• and constantly updated through tension between experiment and theory.

In that sense, quantum theory is a third pole, different in character from purely philosophical theories.

Thus I think it is very promising to treat

Realism, structuralism, and quantum theory
as three positions that coexist in a kind of equilibrium.

This three-point configuration can open contemporary philosophy to a broader public,
connecting it naturally to physics and even to Buddhist thought.

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5. Why quantum theory can serve as a “non-structuralist” critique of realism

5.1 Why quantum theory shakes classical realism

The classical world-view assumes, in effect:

“Even if nobody is looking, the moon is there,
and its position and momentum are well defined.”

Quantum theory, especially in its Copenhagen-style understanding and in light of Bell’s theorem,
undermines this at a very basic level.

• Before measurement, properties such as position and spin are not simply well defined.
• Measurement is not “reading off a pre-existing value,”
  but something closer to an event of fixing a relational state.
• With quantum entanglement, we are forced to treat “here” and “there” as two parts of a single, indivisible whole.

This world-picture does not sit well with classical realism’s narrative:

“There is a hidden essence somewhere, and science’s task is to uncover it.”

However, we must be careful.
Within quantum theory there coexist both

• more instrumentalist / anti-realist interpretations (Copenhagen, information-theoretic views), and
• more realist interpretations (Many-Worlds, de Broglie–Bohm, GRW, and others).

So if we say, “Quantum theory = anti-realism,” we are over-simplifying.

It is more accurate to say:

Quantum theory has pushed classical realism’s basic assumptions
(locality, determinism, and properties independent of measurement)
to the point where they cannot be maintained in their naïve form.

5.2 A “conspiracy” between structuralism and quantum theory

If we compare realism, structuralism, and quantum theory, we get a rough contrast like this:

• Realism
  • Basic unit: “individuals” and “subjects.”
  • Properties are internal to the thing itself.
  • Message: “Truth is hidden in there.”
• Structuralism
  • Basic unit: “relations” and “structures.”
  • Properties are determined by position and difference within a system.
  • Message: “Truth is an effect of the system.”
• Quantum theory
  • Basic unit: “states” and “interactions.”
  • Properties are fixed within relationships of measurement.
  • Message: “Reality is the overall pattern of measurement outcomes.”

Both structuralism and quantum theory shift the center of gravity from substance to relation.
In that sense, they stand in a kind of “conspiracy” against classical realism.

5.3 Structural realism and “quantum structuralism”

In philosophy of science, there is a position called structural realism:

It may be dubious whether “particles” like electrons and quarks truly exist as little beads,
but the mathematical structure of their relations does exist.
That structure is what science gets right.

If we read quantum theory through this lens, it becomes:

Quantum theory moves the locus of reality away from “objects themselves”
and toward “the structure of state spaces, operators, and probabilistic correlations.”

At this point, we are very close to a kind of

• physical structuralism, or
• “quantum structuralism.”

It comes so close to philosophical structuralism that the border between the two begins to blur.

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6. Rewriting spacetime from the viewpoint of quantum theory

Realism, structuralism, and a new spacetime concept

Let us briefly return to the realist premise:

The clearest example of something “real” is a physical object.
It occupies space, persists through changes and deformations, and we can track it.

In that case, reality seems to presuppose spacetime.

So what happens if we start to shake that spacetime concept itself?

Quantum theory, especially in its quantum-information and quantum-gravity frontiers,
is now pressing in exactly this direction.

6.1 Entanglement and the breakdown of “distance”

Quantum entanglement shows us that

• no matter how far apart we separate two systems,
• there can be strong, stable correlations between measurement outcomes.

Importantly,

• those correlations look “instantaneous,”
• but they cannot be used to send controllable information faster than light.

So:

• causal structure (the prohibition of faster-than-light signals) is preserved,
• yet “physical distance” and “relational closeness” come apart.

We therefore need two different notions of distance:

• geometric distance in spacetime, and
• relational distance in terms of correlation and entanglement.

It may be that, in some sense,

Even if things are far apart in space,
they can be “very close” in terms of their relational structure.

6.2 Superposition and the wobble of time

If we take experiments such as delayed-choice seriously, we are led to pictures like:

• Present measurements seem to determine what past “paths” must have been,
• Before measurement, it is unclear whether the system had a definite past at all.

Time then begins to look less like a rigid, one-way river flowing from past to future, and more like:

Until certain relational events occur,
both “past” and “future” exist as overlapping bundles of possibilities.

From the perspective of natural language, we might say:

• Instead of subjects being fixed in advance, waiting for predicates to fill in,
• Predicative events and relations are what bring subjects into being.

That is, a more predicate-centered, “event-first” world-view fits the quantum picture surprisingly well.

6.3 ER=EPR and emergent spacetime

In quantum gravity and holography,
one influential conjecture goes under the slogan “ER = EPR.”

Very roughly:

• EPR refers to quantum entanglement (Einstein–Podolsky–Rosen).
• ER refers to Einstein–Rosen bridges, i.e. wormholes in spacetime.

The idea is that entangled systems might be connected, at a deeper level,
by something like microscopic wormholes.

If this is right, we can think:

What is fundamental is the network of quantum relations and entanglements.
The 3+1 dimensional spacetime we experience is a kind of holographic shadow of that network.

6.4 A categorical world-picture

In the language of category theory, we might put it this way.

• Old spacetime picture (set-theoretic)
  • First there is a container called “space.”
  • Points and objects are placed in it.
  • Nearness and farness are given by metric distances.
• New spacetime picture (categorical)
  • First there is a network of “relations” and “morphisms.”
  • The thickness and patterning of that network appears as “distance” and “geometry.”
  • Things are “close” because they are strongly and directly connected.

In this view,

Spacetime is not the OS, but more like the UI or application layer.
The true OS lies in Hilbert spaces, operators, and the network of entanglement.

This image resonates strongly with the idea that

• classical spacetime is a useful effective theory,
• beneath which there is a quantum relational structure.

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7. Conclusion: The “three-corner equilibrium” of realism, structuralism, and quantum theory

Let me now gather the pieces.

1. Realism
   • A world-view that takes individuals, objects, and subjects as basic.
   • Extremely practical in everyday life and engineering.
   • Classical physics fits comfortably here.
2. Structuralism
   • A world-view that foregrounds relations, differences, and structures.
   • Relativizes meaning, language, institution, and power.
3. Quantum theory
   • A scientific world-view centered on states, interactions, and correlations.
   • Undermines classical assumptions of locality, determinism, and measurement-independent properties.
   • Can be linked to structural realism and “quantum structuralism.”

These three are not a trinity doomed to doctrinal warfare,
but rather the three vertices of a triangulation that lets us locate ourselves more precisely.

• For daily life and technology, we can lean on realist intuitions.
• For society, culture, ideology, and the unconscious, we can adopt structuralist lenses.
• For the physical and spatiotemporal foundations of the world, we can consult quantum theory as a third pole.

On top of that,

• we can translate realism into structuralist language,
• reinterpret structuralism in realist metaphors,
• and express quantum theory in either vocabulary when needed.

All of this is possible, but none of these translations is complete or cost-free.
That is precisely why the coexistence of the three is fruitful.

The coexistence of realism, structuralism, and quantum theory is not about deciding which is “right,”
but about having three OSs available, each suited to different tasks and scales.

Framed this way, we gain a single conceptual map where

• contemporary philosophy,
• modern physics, and
• Buddhist thought

can be discussed together without forcing them all into one dogmatic mold.