Traces of the Real

Traces of Reality

The Process of Elimination
Bernard d’Espagnat gets ever deeper into familiar, and largely friendly, territory.

It’s a chapter about large agreements and small disagreements as these particular critics seem to agree as much as disagree with him.

His major challengers and comrades will be Michel Bitbol and (less prominently) Hervé Zwirn.

Form vs Content
D’Espagnat first examines Bitbol’s “verbal issues” and questions about d’Espagnat’s logical arguments.

Then he moves on to more substantive issues.

Veiled Reality vs Dualism
Bitbol suspects “Veiled Reality” is dualistic.

Classically dualism means there’s mind and there’s matter, though even in Descartes’ time philosophers puzzled how the two could interact.

Materialists later on would say mind is just a manifestation of matter, but d’Espagnot says Bitbol isn’t a materialist.

D’Espagnat says if Bitbol’s objection is about interactions then he’s got it wrong.

D’Espagnot says he doesn’t believe mind and matter are the building blocks of “reality as it really is.”

Instead mind and matter emerge from the ground reality, an “Independent Reality.”

Coming from the same source mind and matter aren’t fundamentally split from each other.

“Veiled Reality” vs Veiled Reality
Next is the issue of whether the term “Veiled Reality” is misleading.

Although d’Espagnat admits the term might suggest a world of objects behind some veil, he said it’s just simply hard to compress the concept into two words.

He admits he used to prefer a “non-watered-down structural realism,” but since then he’s undergone an “evolution” rather than a “revolution.”

Objectivist Language vs Objectivist Philosophy
D’Espagnat says it’s convenient to talk about an instrument dial pointing to a particular spot.

But objectivist language is a matter of convenience, it’s not to taken literally.

D’Espagnat uses that kind of language to talk about “impressions,” not events independent of “the existence of thought.”

In any event, it seems Bitbol acknowledged the misinterpretation and moved on.

D’Espagnat’s approach is an “essentially negative approach” of showing what capital-R “Reality” can’t be: plural, atomistic, embedded in space-time, for instance.

He says Bitbol eventually realized this about d’Espagnat’s position.

Broglie-Bohm vs Dualism
D’Espagnat says the Broglie-Bohm models are logically consistent and follow a mostly “classically dualistic conception.”

But the subject still isn’t “face to face” with the world as there are hidden variables and a “Universal nonseparable wave function.”

Hence Broglie-Bohm isn’t a fully classical dualism.

“A Priori” Dualism vs Observed Dualism
Kant used “a priori” arguments to support his “thing-in-itself.”

But can we use the data of modern physics instead as d’Espagnat has done?

Bitbol said d’Espagnat based his arguments not on quantum mechanics in general.

Rather he based it on a particular interpretation, one that rejects hidden variables.

D’Espagnat says he’s made no secret of that.

Science chooses among various explanations and tends to be wary of “an all-powerful Zeus, for example.”

Bitbol calls these factors “ampliative” criteria.

And even Bitbol acknowledges that Bohm’s theories lead to a “crisis in atomism” with their “nonlocality and contextuality.”

D’Espagnat says nonlocality doesn’t force the “thing-in-itself” to be inaccessible.

But it undermines the hope that “the Real” can be progressively unveiled.

Knowledge Of vs Knowledge About
Bitbol complained that d’Espagnat’s book Veiled Reality talked about “Independent Reality” as “something.”

But wouldn’t that make this supposedly independent reality an empirical reality?

D’Espagnat says he was careful to say the data would have “something to do” with this reality.

It would be knowledge about this reality, but not knowledge of this reality.

To Sketch vs Not to Sketch
Bitbol says Kantian and neo-Kantian philosophers would object to the idea that an “Independent Reality” is “prestructed.”

D’Espagnat says Bitbol needs to do more than just cite possible objectors.

He needs to present an actual argument.

Bitbol says d’Espagnat is implying observed phenomena lets one “sketch” various features of “Independent Reality.”

D’Espagnat says that to talk about sketching is misleading.

By giving up on the “locality principle” he’s also giving up on “sketching” Independent Reality.

Nonetheless d’Espagnat acknowledges that it’s not just a process of elimination.

He does conjecture that observational data may “in a distorted and incomprehensible way” somehow reflect some structures of “the Real.”

Reflected Reality vs Reflected Thought
Bitbol wonders if maybe predictive laws should be considered “distorted reflections” of our own mental contributions rather than of some “Independent Reality.”

D’Espagnat says it’s important to distinguish between what’s sufficient and what’s necessary.

Of course “our perceptive” context is important, but probably not enough to produce those perceptions.

Furthermore, anyone can come up with an interesting principle and follow its consequences.

One can choose to believe all connections between perception and reality are illusory.

But that doesn’t mean you’ve proved your case.

In the end d’Espagnat remains confident of his “prestructure” hypothesis, though it’s “but a plausible and admittedly unverifiable conjecture.”

Evidence vs Other Factors
Bitbol and Zwirn also wondered if one theory could be replaced by another for reasons other than evidence.

D’Espagnat replies that you can’t tweak a “realist local theory” and make it work.

Nonlocality isn’t nudging one theory out of the way—it’s demanding a different theory.

If Zwirn and Bitbol believe perceptions come solely from us, then we could believe in an experimentally refuted theory.

This may be somehow “rational” but a scientist won’t follow such a path that undermines “science and empirical knowledge in general.”

Bitbol proposes some kind of transformation groups that would explain our sensory data’s “structural invariants.”

D’Espagnat thinks the analogy from group theory is inexact.

In any event, it’s not particularly interesting that nonlocality could appear in some “acceptable realist theory.”

What’s important is that it tells us we can never use a local realist theory to explain all of our observed data.

Nonseparability vs Unity
D’Espagnat admits he went too far in saying the nonseparability of Independent Reality implies some kind of unity in that Independent Reality.

He agrees with Bitbol that this statement demands a principle of the excluded middle such that rational categories cover all that is possible.

The transcendent may not be so intelligible.

Instead of Plotinus’s “One” we should think of a unity that is “the absolutely inexpressible” (pantè aporeton).

This view is still consistent with the (unprovable) view that “poetry, music, painting etc.” may provide us with glimpses of “the Real.”

Similarly, physical laws and their mathematical structure may be some sort of “traces” of an underlying structure.

Nonetheless the connection between those traces and that structure “may well be undecipherable.”

This is definitely less than what “structural realism” would expect.

Critic vs Critiqued
D’Espagnat turns from being critiqued to critiquing Bitbol and Zwirn.

He doesn’t see how replacing a static “a priori” with a functional one improves matters.

Either way, how do you explain how Newton’s law of gravity ended up with its precise form?

D’Espagnat says it “partakes very much of utopia” to expect formalism to overcome observation, which is what he thinks Bitbol believes.

An all-encompassing theory of symmetries and so on is unlikely to render it immune to experimental contradiction.

Furthermore, quantum theory’s axioms (a framework theory) may someday be justifiable just on their formal basis.

But those axioms form the basis of quantum theories, and these are theories “in the ordinary sense.”

And it’s those ordinary theories that provide the evidence against locality, for instance.

Because “all men, all civilizations” share the intuition of a reality outside of us, d’Espagnat is willing to give up on Independent Reality only if it’s proved false.

And it’s a conjecture that can’t be proved false.

Maybe some day a conjecture of greater plausibility will supplant the concept of an Independent Reality.

For now, Bitbol’s conjecture doesn’t do that.

Bitbol is reverting to a medieval approach of arguing from the general to the specific, says d’Espagnat.

As for Zwirn, d’Espagnat heartily approves of his analysis of modern science’s conceptual challenges.

D’Espagnat believes Zwirn commits some minor errors in summarizing d’Espagnat’s approach.

It’s not based on “structural realism,” which Zwirn seems to imply.

However, these aren’t a big deal, and the two thinkers agree on much, says d’Espagnat.

In fact, he says Zwirn may have come up with an even more detailed version of “Veiled Reality” than he has.

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