Posts Tagged ‘quantum physics’

Materia Prima

10 December 2012

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The Beginning of the End
So this is it for me and Bernard d’Espagnat’s On Physics and Philosophy.

In the final chapter d’Espagnat allows himself to speculate on the philosophical and spiritual importance of his veiled reality (which he capitalizes) in particular, and the results of modern physics in general.

The chapter is entitled “The Ground of Things.”

It is in these concluding sections that d’Espagnat makes his final defence of a materia prima, a mind-independent reality, before the objections of both realists (who concentrate on empirical reality) and antirealists (who say mind is all).

Some of those arguments say there’s no reality-in-itself, some say it exists but is inaccessible, and others say empirical reality is “reality.”

Kant vs d’Espagnat
D’Espagnat believes “the Real” is a mystery as it is (in his opinion) not accessible through discursive knowledge.

He notes Immanuel Kant distinguished between phenomena and “reality-in-itself,” but disagrees with Kant that a mind-independent reality is just a boring “limiting concept” filled with “pure x.”

Cassirer vs d’Espagnat
Ernest Cassirer strongly objected to being content with a “mystery,” which he felt would be an unbearable block to scientific inquiry.

D’Espagnat says when possible the search for clarity is admirable, but the true spirit of science is to follow where the facts lead it.

The quantum entanglement shown in “Aspect-like experiments” (by Alain Aspect and others) are just part of our evolving scientific knowledge.

Materialists vs Mystics
Sometimes one should approach “mystery” the way mystics, poets, or composers have done so (though more often in the past).

Realists (materialists) have no reason to believe they hold all the keys to knowledge, even in principle.

As for the antirealists (and instrumentalists), if they think reality is something we ourselves build up, then mystery can hardly be called an exceptional “illusion.”

Affect vs Effect
The “affective” element of human existence is an aspect that seems to circumvent our rationality.

Kant felt the “affective mind” was not “ordered on concepts” and therefore could shine no light on Being.

D’Espagnat is more sympathetic to Descartes. Thought leads to the self-evidence of existence (“I think, therefore I am”), but d’Espagnat says just as self-evident will be our “joys and pains.”

We base our conjectures on what we know most intimately, and what could be closer to us than our “affective consciousness”?

This too should be able to inform us of Being, perhaps in some circumstances even better than science can.

Realism vs “the Real”
We can take a very realist position and imagine that if mankind disappeared the stars would continue in their courses.

This is an argument for a mind-independent reality—just not the one d’Espagnat has in mind.

D’Espagnat says just because our present existence is usually most conveniently described in realist terms (such as conventional space and time) doesn’t mean the realist position is actually true.

Even particle physicists who use the realist language of minuscule points and well-defined trajectories know that’s not what’s “really” going on.

Radical Idealism vs “the Real”
On the other hand radical idealism believes there is no reality outside the mind.

In other words, there’s no mind-independent reality.

D’Espagnat says his earlier arguments, either based on no miracles or intersubjective agreement (see chapter five) undermine idealism but not his veiled reality position.

Mathematical Realism vs “the Real”
Whether it’s “Pythagorism” or “Mathematical Platonism” there’s a belief that mathematical developments are discovered not created.

Again, this would be a mind-independent reality, but mathematically based.

Physical reality is either grounded on a pre-existing mathematical reality or there’s some strong connection between the two.

D’Espagnat reminds us that quantum formalism refers to observational predictions.

It’s possible “the Real” is mathematically based, but quantum theory isn’t going to get you there.

Brains in a Vat vs “the Real”
D’Espagnat disagrees with Hilary Putnam’s thought experiment that places brains in vats.

Connect electrodes to the brains and some supersmart being could send (in theory) images and other sensations directly to the brain.

Putnam says a vat individual could not truthfully say, “We are brains in a vat.”

That’s because his concept of a vat is based on an illusion.

So there’s no connection between this particular version of a “ground of being” and our knowledge.

D’Espagnat disagrees with the assumption that knowledge springs only from the senses.

Also, Putnam’s imaginary statement refers to specific entities. D’Espagnat’s concept of “the Real” is “conceptually prior to any such description.”

Self-Modification vs “the Real”
Francisco Varela and collaborators proposed “enaction” theory.

The brain’s main function is to modify its internal states rather than reflect the external world.

External reality is neither a projection of our mind’s contents nor the source of those contents.

There’s no need to imagine a “pre-given” reality.

D’Espagnat faults Varela’s book for vague terminology.

Does Varela mean “empirical reality” or “mind-independent reality” when he talks of “reality”?

Is the “subjective” an individual’s subjectivity or intersubjectivity?

D’Espagnat disagrees with Varela’s use of “secondary qualities” such as colour to make his arguments.

Even Varela’s arguments about attention and perception fail to convince d’Espagnat.

The mind may display selective attention but that’s a far cry from proving that mind and world somehow arise together.

Structure vs “the Real”
Some people say there’s no reality-in-itself, some say it exists but is inaccessible, and others say empirical reality is “reality.”

D’Espagnat says arguments against veiled reality will fail if they’re based on discursive (descriptive and rational) knowledge.

In other words, arguments based on what structures we see or don’t see are irrelevant to “the Real” as “the Real” doesn’t have structures in the way we’re accustomed to think of them.

Buddhism vs d’Espagnat
D’Espagnat notes Varela’s frequent references to Buddhism.

Buddhism speaks of “sunyata” or “emptiness” in rejecting objects in the world as intrinsically existing in the way we perceive them.

Furthermore our living “selves” have no absolute existence as individuals.

D’Espagnat hopes his veiled reality viewpoint will interest Buddhists, especially as there’s a pretty thick veil between consciousness and “the Real.”

Heisenberg vs “the Real”
D’Espagnat rejects Werner Heisenberg’s (posthumously published) view that empirical reality is a product of our human-made knowledge.

Heisenberg felt there were various “regions of reality” such that our knowledge of biology, for instance, weren’t entirely dependent on our knowledge of physics.

Heisenberg did think there might be something that’s “truly real,” vaguely reflected upon human consciousness.

However, he felt this level of reality would still be situated within ordinary space and time.

It’s on that count that d’Espagnat rejects Heisenberg’s arguments as irrelevant as “the Real” is not located in space and time.

Pro vs Con
In the end Heisenberg finds arguments both for and against a “ground of things” dubious.

You can argue against a “ground of things” but only in the sense of a “pregiven,” describable “world-per-se.”

D’Espagnat finds the “pro” arguments based on “commonsense” or a pre-existing mathematical reality also unconvincing.

D’Espagnat believes a “more fact-based reasoning” is called for.

Universality vs Events
D’Espagnat says over the past half-century interest in chaos and complexity led some scientists to demote scientific laws and promote the role of the “event,” previously seen as more or less accidental.

He says he argued against rejecting the “universal” in a 1990 book.

He’s more ambivalent about the emphasis on “events,” which he says takes place within empirical reality.

That reflects the way we’re “apprehending the Real” but doesn’t meant that’s what “the Real” is all about.

For instance, we don’t see objects as nonseparable, but that’s what quantum theory tells us.

D’Espagnat says Edgar Morin and others in this school of thought have somewhat retreated from their emphasis on events, complexity, and disorder.

Morin acknowledges that “Aspect-type” experimental results have shown some limitations in his approach.

Nominalism vs “the Real”
D’Espagnat is unimpressed with the revival of nominalism among “cultivated, literary, avant-garde people.”

It’s a belief system promoted in the Middle Ages by William of Ockham and others.

Nominalists nowadays reject the universal while applauding individual initiative, which they feel is a product of individual knowledge.

The problem is that nominalism is an all-encompassing philosophy, referring to all things, not just living beings.

The discrete atoms of classical physics have given way to “collective modes of existence.”

And again such arguments apply to empirical reality not “the Real.”

D’Espagnat vs the “Enlightenment”
D’Espagnat believes many sophisticated members of society are still enthralled by outmoded ideas of the “Enlightenment” (d’Espagnat’s quotes).

D’Espagnat acknowledges that research on chaos and events may eventually back nominalism.

However, he things quantum theory and inseparability will win out.

Spinoza vs “the Real”
D’Espagnat cautions against thinking Spinoza was a committed materialist when he talked of “God, in other words, nature.”

Although Spinoza’s natura naturans sounds like “the Real,” his natura naturata sounds like phenomena.

D’Espagnat does not agree there’s a willful, personal God behind all this, however.

Veiled reality is not “intelligible,” unlike Spinoza’s view of Substance.

Phenomenology vs “the Real”
Classical physics introduced mechanical, then mathematical, idealizations of objects.

How things supposedly “really are” became separated from our “direct experience.”

Quantum theory reintroduced a role for the human mind to account for our experiences.

In some ways quantum theories reinforces phenomenology.

Phenomenology sees an act of creativity in the human mind.

It takes various pieces of sensation and constructs some entity that shares these qualities.

However, on some level the source of these sensations still independently exists.

Quantum theory states that some physical quantities can only be observed through human intervention, thus undermining phenomenology’s belief in independently existing sources of phenomenon.

Modern “Sages” vs “the Real”
In “developed” societies there are “sages” who take rather contradictory views.

They say there is a reality independent of us.

But they also say it’s “obvious” we rely on our perceptions to gain access to that world.

So they conclude it is illogical to speak of an “unreachable” reality.

We should make only statements relying on sense data or tautologies (statements that are always logically true).

However, d’Espagnat continues to oppose the view that our perceptions necessarily reflect reality as it really is.

Our modern “sages” try to combine realism and positivism, converting “reality-per-se” into “observation-per-se.”

But there is no “observation-per-se” as observations involve human intention and selection.

The Describable vs “the Real”
If we reject the materialists’ rejection of “the Real,” does that force us into the camp of the radical idealists?

D’Espagnat says we shouldn’t confuse “the Real” and “the describable.”

First, existence takes precedence over knowledge.

Secondly, there is something that says “no” to any arbitrary constructions of reality.

Third, it’s hard to imagine an “a priori” that evolves.

And fourthly, there are universal laws that make predictions, and it’s hard to envision how laws could do so unless you believe in miracles.

Even Michel Bitbol and Hervé Zwirn have not entirely rejected the concept of “the Real” even as they critique it.

D’Espagnat says thinkers should avoid pushing deductive reasoning into areas where it may not strictly apply.

As a sidenote, d’Espagnat says classical instrumentalism believes a concept’s meaning and “reference,” the collection of data about the concept, are the same.

Even if you replace “data” with “prediction” it’s not a universal position as predictions require a predictor.

And that predictor is some being who’s doing the predicting.

Laws vs “the Real”
Bitbol and Zwirn may move a bit toward Platonism when they acknowledge something may constrain us that is not entirely attributable to us.

However, they believe this “something” is totally inaccessible.

D’Espagnat disagrees, and thinks Plato would disagree too.

“The Real” must have some influence on empirical reality’s structure as Maxwell’s laws (for instance) are obeyed by phenomena.

D’Espagnat’s “extended causality” links not instances of phenomena but rather phenomena and “the Real.”

These structural “extended causes” move beyond Kantian causality and recall Plato’s Ideas.

Structures vs Hints of Structures
D’Espagnat says “the Real” is prior to mind-matter splitting, so the mind may detect hints of the mind’s source, which is “the Real.”

That veiled reality is not the same as the underlying reality described by structural realism.

D’Espagnat says mind-independent reality is not the source of our physical laws. At best these laws are distortions of the “great structures” of “the Real.” At worst they’re just very obscure “traces.”

In the end “the Real” isn’t describable, indescribable, or party describable.

The first two options imply a total presence or lack of description, and the third option implies “the Real” has parts, which isn’t the case, says d’Espagnat.

Conceptualization vs Meaning
If “the Real” can’t be conceptualized can it have any “meaning”?

D’Espagnat cites Zwirn’s argument imagining a creature as far ahead of humans as humans are ahead of dogs or monkeys.

We can conceptualize things that dogs or monkeys can’t, so surely a superhuman being could conceptualize things we can’t.

D’Espagnat believes that poets can allude to things that we somehow know exists even if these concepts can’t be made explicit.

Plato’s Cave vs “the Real”
At first glance Plato’s Cave approximates d’Espagnat’s view of veiled reality.

It suggests the emergence of (shadowy) empirical reality (seen in the cave) from “the Real” (the porters who place their Platonic Ideas in front of the light).

However, the fable doesn’t deal with how consciousness (the prisoners) would have emerged from “the Real.”

Furthermore, “the Real” cannot be separated into parts (while the porters hold separate objects).

We cannot conceptualize “the Real” yet Plato conceptualized his Ideas.

Finally, even without prisoners there’d still be the shadows, while in d’Espagnat’s system phenomena would exist only in relation to consciousness.

Traditional Thought vs “the Real”
D’Espagnat warns against a syncretism of old cultural elements and new philosophical points, but he wonders if “the Real” has any bearing on traditional systems.

Religions speak of an “immorality,” which suggests some absolute time that physics no longer can support.

However, perhaps the other term “eternity” suggests escaping this illusory time.

And perhaps there is a “continuous creation” of Being in a process independent of time.

Heisenberg vs d’Espagnat
Heisenberg, says d’Espagnat, doubted thought could illuminate deep matters as (according to Heisenberg) thought returns to its source.

But d’Espagnat notes that new science has allowed us to move past old science’s viewpoints, such as materialism.

So thought has been able to illuminate some deep matters.

Platonism vs d’Espagnat
D’Espagnat sees similarities between his view of causality and Aristotle’s.

Aristotle was a realist and was concerned with causality not just in the realm of phenomena but in “reality-in-itself.”

Furthermore, Aristotle was not beholden to the idea that causes precede effects.

Instead there could be “final causes” to which things might tend under the influence of Aristotle’s God.

As d’Espagnat’s veiled reality is beyond time, “the Real” could impart such a “final cause” on empirical reality.

Also, Aristotle’s interest in causation beyond mere phenomena reminds d’Espagnat of his own interest in causation between “the Real” and empirical reality.

Aristotle distinguished between “power” and “act” while Newton supposedly saw just “act.”

Aristotle saw matter as the seat of a vague potentiality.

Materia prima is pure potentiality.

“Informed matter” exists on more and more complex levels. Simple beings can be the “matter” for more complex beings.

These complex beings in this process are more “real” as their potentiality is expressed.

Therefore the deep meaning of reality lies not in the tiny components of complex beings, but rather the meaning is the complex beings themselves.

In a similar fashion, in empirical reality the wave functions have an “epistemological reality” at a lower level than, say, macroscopic objects in the wake of decoherence.

Although Heisenberg did not cite decoherence he did ponder the possible role of wave functions as a “materia prima.” Abner Shimony went on exploring this issue.

However, they’ve both admitted it’s hard to formulate these ideas precisely.

Plato vs d’Espagnat
As for Plato, d’Espagnat reminds us of his earlier concerns about the Plato’s Cave.

However, for Plato the deeper meaning was not in the things themselves.

They didn’t reside just in “us” either. He wasn’t a radical idealist.

Platonic Ideas (and his concept of the “Good”) bear resemblance to “the Real.”

However, Platonic Ideas are conceptualizable while “the Real” is not.

Many scientists believe, still, that analyzing more and more sense data will get us closer to the deeper meaning of reality.

However, advances in science have relied on a “rapprochement” between science and a philosophical position (Platonism) that questions such a program.

D’Espagnat notes that “Platonism” is a term nowadays often interpreted as “Pythagorism” with real mathematical objects.

D’Espagnat does not agree with “Pythagorism,” but notes that there’s some relationship between it and Platonism.

Even veiled reality has a smidgeon of Pythagorism in it as empirical reality’s objects are somehow a dim reflection of “the Real.”

Einstein vs d’Espagnat
Albert Einstein appears to have believed “the Real” could in principle be apprehended in its details, even if in practice that was rarely possible.

However, the goal remained to explore this deeper world by discovering universal laws.

Einstein also believed in three levels of religious experience.

The first was based on fear, the second morals, and the third transcends ordinary human views of God.

At this third level, Einstein thought, a sublime order is reflected in nature and in thought.

Even scientific materialists no longer believe the common materialism that the mass media disseminates.

However, there have also been developments that make us question some of Einstein’s philosophical positions.

D’Espagnat sees some compatibility between his views and Einstein’s even if Pythagorism doesn’t have to be entirely correct.

“The Real” does not have to be totally intelligible.

The human mind may tend toward the structures and qualities of “the Real” in the sense that Max Planck had a strong affective experience in his theoretical work.

It’s not necessary that mathematics reveals everything about “the Real.”

Rather, as long as we have some concept of “the Real” that we can tend to, the structures and qualities of the mind may be drawn to it even as it never fully understands it due to the mind’s limitations.

The Spiritual vs the Scientific
Maybe this idea is closer to Einstein’s third-level religious experience rather than a completely knowable “Real.”

The human mind tends to quest and exploration, though never able to fully accomplish what it desires.

Einstein was still grounded in physical materialism.

Later developments in physics have shown us something more human-oriented. We can’t limit Being to just material components.

The mind may somehow “recall” aspects of Being as consciousness is not just a product of matter.

Archetypes of some of our feelings may lie with “the Real.” There’s no way to prove this, or disprove this.

But crucially we can no longer see science as an impediment to the “spiritual impetus that moves mankind,” an impetus, according to Einstein, that makes us desire to live “the whole of what is.”

And it is an impetus that possesses both unity and meaning.

Making an Appearance

8 December 2012

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Mind the Details
Bernard d’Espagnat delves into finer and finer distinctions between his veiled reality position and similar (though not identical) views.

The eighteenth chapter of his On Physics and Philosophy is entitled “Objects and Philosophy,” and there’s only one chapter to go after this.

Philosophers vs Consciousness Researchers
D’Espagnat says he takes mostly a philosophical approach in this book.

Philosophers question the basis of our reality while consciousness researchers (such as neurologists) take physical realism as a given (whether they’re conscious of this or not).

Mind vs Reality
Radical idealists, who think mind is “primeval,” may wonder about the relationship between mind and “basic reality.”

Supporters of d’Espagnat’s “veiled reality” or “open realism” approach are even more motivated to investigate.

Truth vs Reality
A physical realist can say that a true statement is “adequate to what reality really is.”

This is the “similitude theory” of truth.

Reality vs Representations
But if we don’t have access to reality as it “really is” then we might say we have access only to “human representations” of “the Real.”

Instead of worrying about whether statements are true to reality you might worry more about the verifiability of statements.

Knowable vs Unknowable Reality
Another problem with the “similitude” approach is that quantum mechanics, the best model of the world we have, fundamentally deals with observational probabilities not plain and simple facts.

Even resorting to a Broglie-Bohm approach doesn’t help as “hidden variables” will be inaccessible to the observer even in principle.

Idealism vs Veiled Reality
A radical idealist or Kantian rejects the similitude approach anyway.

A supporter of the veiled reality approach has to take a somewhat nuanced tact.

Very broad statements about physical constants or “existences prior to knowledge” may hint at “the Real” without claiming to say anything directly about “the Real” as it “really is.”

Appearances vs Veiled Reality
If we’re not supposed to trust in “appearances” then what is reality really like?

We might think that “the Real” is just an updated version of “appearances.”

Or maybe mind-independent reality is so independent that it’s entirely inaccessible.

D’Espagnat says both approaches are too extreme.

Causal Links vs Predictive Laws
We like our ordinary, everyday version of “realism” because it lets us imagine particular cause-and-effect relationships.

It’s easier to explain things when we can point to particular causes rather than just patterns of observational predictions.

D’Espagnat says some causal links are genuine and independent of us, but our interpretation of these links is very much our own.

For instance, causality is closely related in our minds to the notion of “will,” which entails a very anthropomorphic (human-centred) view of reality.

Intersubjective Agreement vs Appearances
But what if a group of humans (and maybe even non-humans!) agree on certain observations?

D’Espagnat says that this agreement combined with rules of observational prediction mean this is our “reality.”

Saying they’re just “appearances” is misleading. It’s a kind of “reality.”

However, modern physics reminds us that humans tend to “reify” (think of the world as a set of objects).

So we still have to keep in mind that empirical reality is not the same as “the Real.”

Empirical Reality vs Mind-Independent Reality
Although d’Espagnat is comfortable with the term “reality” to describe our empirical reality, he says we have to remember these are two “orders” or “levels” of reality.

Empirical reality isn’t just a mere variant on “the Real.”

Identity Theory vs Efflorescence Theory
In some of the more nuanced sections of the chapter d’Espagnat makes a distinction between identity theory and efflorescence theory.

Identity theory states that a genuine sensation or awareness (perhaps even thought in general) is traceable to neurons or their components.

The material aspect of these neurons is the ultimate cause of our sensations.

Efflorescence theory attributes sensations and awareness to “neuronal activity” rather than the material aspects of neurons or their components.

Strong vs Weak Completeness
D’Espagnat’s main line of attack against identity theory is the completeness principle.

In its strong version, quantum mechanics is assumed to be able to describe anything at all.

In its weak version, if any theory can describe something then quantum mechanics can do so as well. This leaves open the concept of hidden variables.

Since quantum mechanics is antirealist it’s hard to imagine how the strong completeness principle is compatible with identity theory.

Even if you take the weak version of the completeness principle all you can conclude is that the identity theory may be true—but we can never show it to be so.

But what if you reject the completeness principle entirely?

If you used the Broglie-Bohm model you’d still have to deal with an entangled wave function, so sensations can’t be attributed just to some limited coordinates of a particular neuron.

Or you can take the Roger Penrose approach by adding nonlinear terms to the Schrödinger equation.

D’Espagnat says that approach may work, but he finds it too ad hoc. It’s also work still at an early stage, yet to face the scrutiny a full theory would need to endure.

Brain vs Neuron States
Now, efflorescence theory relies on neuronal activity not the material aspects of neurons to explain sensation, awareness, and (perhaps) thought itself.

But neurologists believe brain states not neuronal states are what drives awareness. You can’t pinpoint a particular neuron or group of neurons that are responsible.

It’s the collective action spread across the brain that is associated with awareness.

D’Espagnat notes the parallel to quantum entanglement.

Protomentality vs Mentality
Alfred North Whitehead and other thinkers in the past have wondered if simple organisms or even inorganic entities can have awareness?

Abner Shimony’s “potentiality” might satisfy some objections to this concept of protomentality.

Various entities have the potentiality of consciousness, but this potentiality isn’t actualized unless a nervous system is present.

Consciousness vs Components of Consciousness
As a final objection to the efflorescence theory, d’Espagnat says that any component we cite will be part of our empirical reality.

Empirical reality depends on our consciousness.

Therefore how can something that depends on our consciousness be the cause of our consciousness?

D’Espagnat vs The “Received” View
The “received” view that thought is produced by matter is, according to d’Espagnat, “slightly useful” as a model but must be rejected as a plausible philosophical stance.

Relative Quantum States vs Relative Consciousness
Because the observer decides what to measure and how, quantum states are “relative” to these procedures.

However, some quantum rules may be considered “in isolation.” They’re not predictive observational rules and hence don’t involve probability.

They’re more like descriptions.

However, to understand the quantum world you have to consider all quantum rules not just pick and choose the non-probabilistic ones.

D’Espagnat says states of consciousness are somewhat similar.

Definite vs Indefinite States of Consciousness
Imagine a sealed-off laboratory. Paul makes a measurement. His state of consciousness is definite but Peter doesn’t know that until Paul, say, phones him with the measurement.

This is a version of Wigner’s friend, and can be extended over and over again, with an observer outside a sealed room, which contains an observer outside a sealed room, etc.

Peter thinks Paul’s state of consciousness is not just unknown (before the phone call) but also undefined. It’s a superposition of possible results (pointer values, for instance).

Yet once Paul makes the measurement, Paul’s state of consciousness is definite from Paul’s point of view.

Consciousness vs The Absolute
This apparent conflict doesn’t change the fact that physics is all about predicting observations, says d’Espagnat.

However, there’s a related issue.

We shouldn’t think that “predictive states of consciousness” are like some Absolute or can even be a substitute for the Absolute.

Quantum states are relative, and so are states of consciousness.

More precisely, states of consciousness that are predictive are relative.

Physical vs Mental
So we see some sort of “solidarity” between the physical and the mental, but that doesn’t mean the mental can be reduced to the physical.

Wigner’s Friends vs Ultimate Reality
The series of “Wigner’s friends” who occupy increasingly large rooms is suggestive of an ultimate reality that we cannot gain access to. Wigner’s friends don’t have access to the overall wave function.

Predictive vs Non-Predictive Consciousness
However, nothing prevents us from pondering non-predictive states of consciousness.

When Paul makes the observation, his state of consciousness becomes well-defined. It’s no longer predictive.

Veiled Reality vs Co-Emergence
Michel Bitbol, Hervé Zwirn, and other authors speak of thought and empirical reality “co-emerging” at the same time.

It’s a “self-qualifying” process by which structure emerges from an initial and total lack of structure.

D’Espagnat says his veiled reality viewpoint has an “ultimate ground” endowed with general structures even if they are “far from being knowable.”

This ultimate ground may form the basis for not just scientific laws but also creative and mystical endeavours.

Emergence vs Non-Emergence
So, according to d’Espagnat, structures emerge but don’t co-emerge. They pre-exist.

Co-emergence serves merely to connect consciousness and empirical (not ultimate) reality.

D’Espagnat acknowledges that in the past he has talked of consciousness and empirical reality existing “in virtue of one another.”

This does not mean that empirical reality emerged from consciousness.

Furthermore, these words are meant to be evocative rather than a precise philosophical statement.

He reiterates the impossibility of appearances, which depend on consciousness, somehow creating consciousness.

Indexed vs Non-Indexed States of Consciousness
Adopting Bitbol’s terminology, d’Espagnat says some beings may possess non-indexed states of consciousness.

That means these states of consciousness are not relative to any particular experimental setup.

However, these states of consciousness must therefore be non-predictive.

Microscopic vs Macroscopic
An idealized miniature version of a being would be too small to interact with the environment to become predictive.

In the intermediate state between microscopic and macroscopic, such beings could accurately predict one class of observations but would wrongly predict another class of observations.

For macroscopic beings that first class of observations would still be correctly predictable but the second class of observations would be essentially impossible.

These practical observations are conveniently describable in realist language, while the practically impossible observations are not.

So if we want to talk about co-emergence then we should imagine the co-emergence of “public and predictive” states of consciousness and empirical, physical reality.

This co-emergence is constrained by the class of observations that macroscopic beings can perform.

Co-emergence draws from a mind-independent reality that presumably, according to d’Espagnat, is beyond intersubjective description.

And returning to the idea of potentiality, d’Espagnat says that in moving from the microscopic to the macroscopic the “ontological potentiality” of consciousness becomes empirical actuality.

“The Real” is not in itself thought, but can give rise to thought.

One World vs Many Egos
There appears to be one universe but many minds.

Radical idealists have trouble reconciling this situation.

Schrödinger calls this the “arithmetical paradox” and proposed two solutions.

There’s “Leibniz’ fearful doctrine of monads,” and there’s the belief the multiplicity is only apparent.

Schrödinger preferred the second approach, akin to the Upanishads, which states there is unity behind the illusion.

Veiled Reality vs Radical Idealism
The multiple-room experimental setup showed that predictive states of consciousness are relative.

It’s hard to see how all those observers could be part of just one mind.

However, perhaps various observers are making mutually compatible observations, calculable using the general Born rule.

This is the same as one observer making simultaneous measurements.

This sounds compatible with Schrödinger’s viewpoint.

However, that doesn’t solve the problem of the observer in that sealed-off inner room.

It also doesn’t take decoherence into account.

On the other hand, this decoherence also hides any theoretical possibility of discovering contradictions between multiple minds and the quantum structure of physical laws.

D’Espagnat thinks more work needs to be done on this issue.

Traces of the Real

18 November 2012

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.

It’s Not All in Your Head

11 November 2012

Not Just in Your Head

Veiled Threads
Another chapter down, three more to go in Bernard d’Espagnat’s On Physics and Philosophy.

Chapter sixteen, “Mind and Things,” is (relatively) straightforward.

Having spent much of the book undermining physical realism and its kin, he focuses next on the excesses of empiricism and idealism.

Much less combative in this chapter, d’Espagnat seems sympathetic to many of the approaches he describes.

Sympathetic, yes. In total agreement, no.

Ultimately, he’s laying the groundwork for exploring his “Veiled Reality” in some detail as the book draws to a close in the chapters to follow.

Empiricism vs Metaphysics
Empiricism’s guiding principle: all of our knowledge comes from our senses.

It started by discarding metaphysical sources of knowledge.

It then emphasized the role of “elementary sensations.”

Experience vs Reality
Early empiricists seem to have believed primary qualities were real aspects of real objects.

Even if our knowledge can’t exceed our experiences, if properly used our experiences produce a good picture of reality.

A large number of modern-day scientists hold this view, which is a kind of “physical realism.”

Empiricism vs Knowledge
Initially the Vienna Circle epistemologists more energetically attacked Kantian views than scientific realism.

Nowadays, though, logical positivism is understood in an antirealist sense.

But this creates a problem. If the empirical connection between experience and reality is questioned, then are we back to Kant or the neo-Kantians?

D’Espagnat thinks that this quandary sank the logical positivist agenda, but contemporary physics can still learn from some of their ideas.

Knowledge vs Phenomena
“Phenomenalism” has various definitions.

One version states that “knowledge is strictly limited to the (physical and mental) phenomena,” says d’Espagnat.

Phenomena are just the objects of our (unanalyzed) perceptions or introspection.

So phenomenalism is at best consistent with “open realism.”

This is the “weak” version of realism that d’Espagnat favours.

Phenomenalists vs Physical Objects
Unfortunately phenomenalists are often vague about the reality of physical objects.

The Vienna Circle positivists were suspicious of counterfactuals: “If you put this lump of sugar in water then it would dissolve.”

It’s hard to assign properties such as “soluble” to an object without using counterfactuals.

Phenomenalists vs Paths of Knowledge
Another problem was pointed out by Bertrand Russell.

Unless a solipsist, a phenomenalist accepts the existence of other observers and their assertions.

But then why not accept the existence of sound waves, since they convey messages?

But then you’re getting into back into physical realism.

Private Sensations vs Public Science
It’s hard to get around this problem since we have no direct access to other people’s sensations.

They’re private.

But science relies on communicating knowledge.

That’s public.

Object vs Method
A third problem:

We describe objects by describing how to get sense data about them.

But then as objects get smaller and smaller the description gets longer and longer.

How do you describe an electron as a “construct”?

You could describe a cloud chamber, how it has to be prepared, and then the probability that the set-up will produce the hoped-for observation.

Stability vs Instability
But that gets at a problem when you move from phenomenalism to contemporary physics.

To a phenomenalist, an object of knowledge is a stable pattern of perception.

In quantum physics there are probabilities of state vectors not some “inherent stability” of perception.

Classical Instruments vs Quantum Systems
To address Russell’s problem we can assume a measuring instrument is classical.

That way various observers can agree on a measurement.

Furthermore, our observations agree with the rules of quantum physics, so our sensations aren’t entirely private.

It’s a kind of “mutual agreement” between our perceptions and quantum rules.

However, d’Espagnat notes this solution is a “hybrid” one.

And, he notes, in chapter eight he looked at the problems with saying an experimental apparatus is classical.

Operationalism vs Phenomenalism
D’Espagant likes operationalism, a modified version of phenomenalism.

It deals with how to make observations, and quantum rules for predicting observations are unquestionably accurate.

Conventional vs Radical Operationalism
There’s a conventional version of operationalism that’s “moderate.”

It talks as if there are real properties that are measured.

But as seen in chapter seven this leads to ambiguity.

“Radical” operationalism is more content to just describe measurements.

However, that’s hard to do without specifying the objects being measured.

Intrinsic vs Convenient Elements
“Radical” operationalism may consider some perceived forms to be “elements” of empirical reality connected by empirical laws.

But unlike traditional operationalism, it doesn’t consider these forms to have intrinsic significance.

Perceived forms aren’t the “constitutive” bricks of anything.

The radical operationalist is prepared to discard one set of predictive rules for another if they work better.

And if two sets of rules produce the same predictions then we should accept both.

Deductive vs Inductive Logic
However, radical operationalism relies heavily on induction.

If a rule worked in the past then it must work in the future.

That’s not strictly logical.

Rules vs Explanations
Another problem is that people have trouble seeing these rules as a “genuine explanation.”

So do we need the notion of “cause” beyond the realm of just phenomena?

Phenomenal vs Transcendental Causation
Kantians say that causality is inherent in our a priori understanding, not in the objects themselves.

Abner Shimony notes there are many kinds of causality.

He feels this diversity undermines the universal application of this Kantian claim.

Also, cognitive science has blurred the distinction between the phenomenal and transcendental selves.

Therefore categories of understanding can hardly be limited to just the phenomenal self.

Phenomena vs the Mind
Furthermore, in the past century or two, mathematics and physics have undermined the believe that our understanding of phenomena reflected the ordering principles of the mind.

Therefore Shimony doesn’t believe that only phenomena can be the “causes” of other phenomena.

Shimony’s Causation vs d’Espagnat’s Laws
D’Espagnat focuses on predictive laws in constructing his concept of a “Veiled Reality.”

Shimony puts causality at the root of his ontology.

True, the reliability of predictive laws must have some kind of “cause.”

But d’Espagnat still says he and Shimony have very different views.

Transcendental Uniqueness vs Structure
A basically Kantian approach says a “transcendental object” is the “purely intelligible cause” of various phenomena.

Kant believes that objects exist “per se”—but only in experience.

However, he felt there must be a “cause” of these representations.

The cause will be totally unknown to us, but he still gave it a name: the “transcendental object.”

This unknowable cause is singular.

The phenomena it produces are plural.

Therefore the “transcendental object” is unique.

D’Espagnat already acknowledged (in chapter ten) similarities between Kant’s transcendental object and his own views of extended causality and “ground Reality.”

However, d’Espagnat is willing to accept “some sorts of structures” that end up “implying” our scientific laws.

That structure and that connection to our laws will still be “undecipherable.”

Individual Mind vs Mind in General
Operationalism avoids making ontological statements.

However, someone has to set up and run the experiment, and someone has to be observe the results.

So presumably either an individual “mind” or a “mind in general” exists.

Objective Laws vs Mentalist Consciousness
Jean Petitot says we can be “objective” about the laws of phenomena even if we can’t see what’s behind the phenomena.

Galilean space and time are “mental” concepts.

But these mental forms let us construct the legal rules of phenomena, which become “desubjectivized.”

So “mentalist” or “cognitive” is what’s unique to each person’s consciousness.

Things lying in space are therefore neither ontological nor mentalist.

Objectivity vs Ontology
Petitot says that space and time are the crucial notions in classical physics.

In quantum physics the crucial notion would be probability amplitudes.

But space and time seem independent of us, while probability amplitudes are very much connected to an observer.

D’Espagnat says it’s not a crucial distinction as Petitot separates objectivity from ontology.

Petitot’s approach is what d’Espagnat calls a “weak objectivity” or “intersubjectivity.”

Different observers will get the same measurements under the same conditions.

Assumptions vs Justifications
But d’Espagnat tackles Petitot’s approach on two fronts.

The first objection is that stating a rule and justifying a rule are two different things.

Stating that “reality-per-se” is unobservable creates some interesting consequences.

But the statement is basically an axiom.

Galilean physics can still be explained by the “reality of the accidents.”

The big challenge to realism was quantum physics, not Petitot’s or anyone else’s transcendental claims.

Transcendental vs Individual Subject
The second objection is that transcendentalists create a contradiction when they limit “mentalist” and “cognitive” to individual minds.

Petitot and Kant both believe a transcendental subject is impersonal.

It supposedly conveys a priori sensibility and categories of understanding not limited to an individual.

Kant said his transcendentalism differed from Berkeley’s idealism.

However, Kant’s “empirical realism” is still only empirical.

Objects of experience exist in experience.

But experience requires one or more subjects to have that experience.

D’Espagnat says a “transcendental subject” can’t eliminate the role of knowledge in our experiences.

And knowledge depends on cognition.

That knowledge is then communicated intersubjectively, taking it out of the “private realm.”

Plato vs Galileo
Galileo stressed the mathematical structure of natural laws.

Some people take this as evidence he was a “Platonist.”

Alexandre Koyré said Galilean science started from this belief:

Reason and geometry are enough to acquire “intelligence of the real.”

But Galileo took considerable pains to investigate phenomena.

For him to be a Platonist you’d have to equate what’s “empirically real” with a kind of Platonic idealism.

However, Plato’s cave suggests our pursuit of phenomena will get us only as close as some shadow of the “Real.”

Senses vs Innate Knowledge
Also ambiguous is the notion of what is “innate.”

Both Descartes and Saint Augustine believed we could gain knowledge without use of the senses.

But empiricists believe “reality-per-se” is inaccessible.

So how could we ever experience an independent reality?

Empiricism vs Innatism
If we consider Kantian space, time, and causality then these notions must be innate.

Furthermore, Kant’s categories of understanding are a priori, so they too are “innate.”

But in our “semi-intuitive” world-view we follow sensory evidence as closely as possible, yet interpretation still guides us.

Quantum Mechanics vs Innatism
Quantum mechanics is “weakly objective” hence “antirealist.”

Its view of knowledge is somewhat Kantian, but with a strong dose of operationalism added.

This operationalism prevents quantum mechanics from getting too close to Descartes’ innatism.

Furthermore, the simplicity of quantum rules leads us to infer (unprovably yet irrefutably) a simplicity in the “Real.”

D’Espagnat says this approaches Nicolas Malebranche’s “vision in God.”

Empiricism vs Conventionalism
D’Espagnat says reading between the lines one can see evidence of Henri Poincaré’s “ontological” stance.

Kant believed the axioms of geometry were a priori.

The discovery of non-Euclidean geometries refuted such an idea.

Poincaré saw the axioms as neither a priori nor as experimental data.

They are conventions, he decided.

“One geometry cannot be truer than another one, it can only be more convenient,” he wrote.

The Convenient vs the Real
Poincaré felt the same way about physics.

Experimental data and theories about them are not descriptions of an independent reality.

They are convenient and concise “pictures” to describe observations and connect them.

So, for instance, the ether hypothesis is “convenient.”

Whether or not ether exists is the concern of the metaphysician, not him.

Supporters of “objectivist realism” complain conventionalism favours convenience over truth.

However, both Poincaré and d’Espagnat reply that if rules make the right predictions then we might as well call them “true.”

Knowable vs Underlying Reality
Poincaré says relationships between things are “objective” when they’re “the same for everybody.”

Poincaré says that the relationships between things is “the sole objective reality.”

These relationships cannot be conceived independent of a mind that conceives them.

However, “they are objective nevertheless since they are shared by all thinking beings.”

Poincaré is definitely referring to real, though hidden, objects.

And Poincaré says we can discover true relationships between these real objects.

D’Espagnat says that the only way to make sense of these statements is to believe Poincaré believed some reality that underlies phenomena.

Otherwise it’s hard to imagine how there could be real relationships between real, if hidden, objects.

Separability vs Non-separability
Although d’Espagnat’s viewpoint and Poincaré’s implicit ontology are similar, they differ over “separability.”

Poincaré’s “structural realism” involves “objects-per-se”—unknowable but plural.

D’Espagnat says modern physics does not support separability, and hence there must be “some underlying coherence, or deep unity” to this hidden reality.

Rules vs Ontology
Poincaré believed the equations of classical physics served two purposes.

First, they describe the structure of various laws.

Secondly, they describe the value of certain properties at different points.

Poincaré was happy with the first role.

He had doubts about the second role as he felt equations indicated only what would be observed at those points, not what was pre-existing there.

D’Espagnat wonders if we can give up the second role of an equation’s symbols while retaining the first.

Maybe we could then call this a “structural” realism.

Old vs New Theories
D’Espagnat does note that Poincaré explored ontological issues only with reluctance.

Therefore it would be wrong to attribute this interpretation to Poincaré.

Also, this interpretation has some problems.

As theories evolve, old equations may be seen as merely approximate.

Also, a new theory may have little in common with the old theory.

This would imply the structure of “Reality” is very different under this new theory.

However, normally one could derive the old theory’s equations from the new theory’s equations.

In that case there still might be a meaningful, permanent substratum to reality, despite the objection of radical idealists.

Structural Realism vs Veiled Reality
In the end, d’Espagnat says, structural realism can be justified only after it’s watered down so much it looks like his own “Veiled Reality.”

In the final chapters d’Espagnat says he’ll have to steer between the conceptual difficulties of classical phenomenalism and how physical realism is contradicted by its own science’s results.

Background image: NASA, ESA, J. Richard (CRAL) and J.-P. Kneib (LAM) via www.spacetelescope.org.

 

The Portable Rainbow

7 July 2012

Rainbows

Under the Veil
Chapter 15 (“Explanation and Phenomena”) of Bernard d’Espagnat’s On Physics and Philosophy continues the previous chapter’s exploration of causation and explanation.

With quantum mechanics relying on observation and denying a naive realism, is an empirical explanation good enough?

For d’Espagnat there’s a need to postulate a “Veiled Reality” of which we may only be able to sneak some peeks, if at all.

Nonetheless he believes it’s there.

Prediction vs Explanation
If you measure the state of quantum particles and find a correlation-at-a-distance how do you explain it?

Quantum mechanics is a “recipe” to predict observations from initial conditions. It’s an “explanation” on the level of empirical reality.

If you need some “deeper” explanation about what’s “really” going on you might add “hidden variables” to extend the standard theory.

But then you run into problems with Bell’s Theorem and the experimental results of Aspect and others.

If you don’t have knowledge of a deeper reality, how can an empiricist justify using induction to create laws?

Just because a law summarizes certain observations on certain days, why should we think it’s universal?

Induction vs Unknowable Explanation
For d’Espagnat, a belief in the existence of a deeper reality is enough to ground our use of induction.

We may be incapable of comprehending this deeper reality, but our belief that there is one suggests a connection between empirical reality and an underlying reality.

That belief is enough for d’Espagnat to accept induction without having to justify it every time it’s used.

Even if we don’t know anything much about this deeper reality, there’s still no “logical inconsistency,” d’Espagnat says, in using its presumed existence to justify induction.

Furthermore, this deeper reality—whether “veiled” or even entirely unknowable—will not be an arbitrary reality, d’Espagnat says.

Rainbows vs Quantum Concepts
Although rainbows can’t be directly grasped and manipulated, they’re explained in classical physics.

A description of rainbows might illuminate how we speak about quantum systems.

A rainbow (including its two “bases”) will look different from different locations.

Hence, the particular rainbow someone sees is observer-dependent.

The same reliance on location is true if you set up automatic cameras.

Hence you can’t say that just because we’ve taken a picture of a rainbow that this rainbow “really” existed before that observation.

Similarly, out tendency to “reify” (seeing something as concrete and real) means we jump from an observation to assuming what was observed somehow pre-existed.

If we can argue that a rainbow doesn’t pre-exist, we should be able to argue that a quantum object doesn’t pre-exist either.

Dinosaurs vs Humans
However, surely dinosaurs existed before humans ever walked the earth. No observation was required to bring them into existence.

D’Espagnat says that dinosaur bones are like the pointers of an experimental set-up. We see something and conclude it’s real.

Though d’Espagnat says it’s real, he specifies it’s real in the realm of “empirical reality.”

However, this empirical reality is hardly an arbitrary production. Its qualities are severely constrained, and in the end observers tend to see mostly the same thing.

Explanations vs The Final Key
Classical physics can still provide us with “explanations” as long as we don’t presume they derive from a deeper reality.

D’Espagnat adds that we should not conclude that these explanations are the “final, ultimate key” to understanding the world.

D’Espagnat vs Other Views
I’ve concentrated above on d’Espagnat’s ultimate positions, but here are some examples of how he explains his disagreement with other people’s positions (real or conjectured).

D’Espagnat vs Cassirer
If you see correlations in a quantum experiment then d’Espagnat has trouble imagining Cassirer’s “logical necessity” could explain each particular observation in a sequence.

True, Cassirer could choose (or could have chosen, as he’s now dead) hidden variables, but d’Espagnat says that’s too “metaphysical” for Cassirer, and the Aspect-type experiments have refuted them anyway.

Maybe Cassirer equates “logical necessity” with a pre-existing logos, a primary notion of absolute existence.

D’Espagnat says that whole idea is something the neo-Kantians were trying to get away from, so again it doesn’t sound like Cassirer.

Nonetheless, d’Espagnat says his own position is consistent with considering the “Real” (with a capital R) to consist of such a logos.

D’Espagnat vs Carnap
Carnap says scientists should be more modest. They shouldn’t try to explain the “why” but just the “how” of phenomena.

Carnap’s position is that simply producing entities, such as Driesch’s “entelechy” as an explanation for tissue regeneration, is irrelevant as there are no “laws” connecting conditions and observations.

So what about d’Espagnat’s “Real”? Is it just a meaningless entity?

It doesn’t help us predict anything, so maybe it’s not an explanation at all.

D’Espagnat responds by saying scientists long ago were implicitly believing in the realism of a world ruled by classical physics even if explicitly they concerned themselves with just the laws of observation.

Even some realists nowadays, says d’Espagnat, acknowledge that there could be an underlying reality, not attainable through “discursive knowledge,” that nonetheless grounds our empirical reality.

Furthermore, if laws relate just to our known observations, then what happened before we made those observations?

Carnap, according to d’Espagnat, said laws could exist before such observations but the truth of the laws could not be judged.

D’Espagnat says this amounts to Carnap’s acknowledging a “human-independent reality” that has a structure we might never know.

Since quantum mechanics only predicts observations and does not “explain” underlying reasons, this implies to d’Espagnat that a “Veiled Reality” has a meaning even if we can’t explore it empirically.

But what if we imagine Carnap meant some kind of “linguistic framework” involving “nature” and “existence” that replaced the usual meaning of those terms?

In a world ruled by classical physics it makes sense to speak of “things” and their qualities makes sense.

In a world ruled by quantum physics it makes sense to speak of “sense-data” rather than “things.”

D’Espagnat says this approach works fine for making sure scientific statements are clear.

But it’s not satisfactory from the philosophical point of view.

Carnap, d’Espagnat says, is just “masking” not “eliminating” the connection we make between an explanation of observations and an explanation of what’s going on in some underlying reality.

Since a linguistic framework is “chosen by us” according to Carnap it sounds a bit arbitrary and not like a genuine explanation.

An Influential Relationship

1 July 2012

Influential Arrows

Just Causes and Side Effects
Chapter 14 (“Causality and Observational Predictability”) of Bernard d’Espagnat’s On Physics and Philosophy examines how, and if, we can use the concepts of causation and influence to explain the world.

Reality vs Observations
Taking a break from examining the “notion of reality” d’Espagnat uses this chapter to argue it’s better to predict observations than predict “things as they are.”

Animism vs Empiricism
Aristotle saw causation as related to human will, and even inanimate objects seemed to have some animistic will—as seen when a falling stone somehow desires to return to its natural resting place.

Empiricists went to the other extreme. Physical laws should just be descriptions of events and their regularities. However, what initial conditions are the “cause”? You end up with too many empirical laws.

Mathematical vs Physical Determinism
If two very close points rapidly diverge then they’re not likely to be “physically deterministic.” It’s too hard to calculate their exact paths.

“Strong objectivists” argue that science accumulates knowledge about an underlying reality, not just our experimental observations.

Some strong objectivists argue that “chaotic” behaviour is an example of indeterminism, and others argue initial conditions have to be repeated exactly for us to say deterministic laws apply.

The first approach implies imperfect observations or calculations show reality is indeterministic, but that’s strange since strong objectivists believe in an underlying reality separate from our fuzzy data.

The second approach is a problem since a strong objectivist can’t be absolutely sure the initial conditions won’t be repeated.

Laws vs Predictions
D’Espagnat also criticizes the claim we’ve seen the “end of certainties” just because some calculations make predictions impossible.

He says that’s too harsh as we can still believe in our laws even if sometimes in practice we can make reliable predictions only for the near future.

Classical vs Quantum Indeterminacy
D’Espagnat cautions against regarding chaos theory as some overriding conceptual triumph as it’s grounded on classical concepts of space and time.

Classical physics falters where quantum physics and its apparent indeterminacy excel, particularly on the microscopic level.

Yet d’Espagnat says the defining feature of quantum mechanics is not its indeterminacy but its “weak objectivity.” The theory confines itself to observations of reality, not claims about reality itself.

Individual vs Statistical Determinacy
D’Espagnat agrees with Kant that “regularity in time”—in which one kind of event is followed consistently by another—is a good way to distinguish the empirically real from, say, the events of a dream.

Kant’s “sin of omission” (understandable because of his time and place) was not to consider statistical regularities in which ensemble probabilities are deterministic.

D’Espagnat emphasizes that quantum mechanics makes reliable predictions for observing ensembles of quantum systems, but these are not probabilities of ignorance about individual systems.

At first glance quantum mechanics may seem indeterministic, but if you keep in mind quantum predictions are about observations of multiple systems then it too is deterministic—if only “statistically.”

Laws vs Facts
D’Espagnat warns against “a variant of nihilism” if you don’t pay enough attention to the difference between laws and facts.

He says even Dirac’s musings that universal constants (such as the speed of light) might change over time don’t threaten that distinction.

The nihilistic danger, d’Espagnat says, comes from sociologists, epistemologists, or “pure philosophers” who see in the history of a changing universe a fundamental lack of stability.

They fail to distinguish between laws and facts, or they fail to appreciate the significance of the distinction.

Causes vs Influences
D’Espagnat imagines a Laplace daemon that can possess total knowledge of events in part of the universe.

The fixed speed of light means, in an Einsteinian world, the daemon need only check events in a point’s past light-cone to predict that point’s future.

However, Bell’s Theorem combined with the experiments of Alain Aspect (and others) proved that the locality hypothesis is false.

Add to that the order (in time) of events can vary by reference frame, and we see that (earlier) cause and (later) effect can be ambiguous.

D’Espagnat thus suggests that faster-than-light influences—or “influential relationships”—do exist.

Gestures in Empty Space

23 October 2011

Gestures in Empty Space

Physics vs Philosophy
In the second half of his book On Physics and Philosophy Bernard d’Espagnat explores more of the philosophy and less of the physics of quantum theory, and I’m taking notes to keep track of where he’s headed.

In chapter 13 (“Suggestions from Kantism”) d’Espagnat says that physicists nowadays aren’t entirely sure how their scientific theories and results are to be interpreted.

Science of Reality vs Science of Phenomena
Immanuel Kant steered science away from “reality-per-se” and toward the study of phenomena, so d’Espagnat thinks Kant’s views might be promising.

Kant did not reject the idea of an underlying reality, otherwise he would have discarded the “thing-in-itself” concept.

Kant did, however, say that Pure Reason would not be able to make any pronouncements on it. Beliefs and speculations are fine as long as we don’t call them scientific or rational views, he said.

The Table vs the Representations of the Table
Here is a basic problem: if you look at a table you not only have a representation of that table somehow inside of you, but you also believe there’s a table somewhere out there.

Can we check that this representation is accurate? Well, we can’t check what’s “really” out there since our senses give us just a representation of the table.

Space vs Experience
Kant argued that the very concept of space and spatiality was “a priori.” We’re more or less born with it as we need to peg various bits of sense data somehow in relation to each other.

D’Espagnat disagrees, saying the same argument could be made about riding a bicycle or learning to swim. He says Kant, living in a time ignorant of the evolution of species, would also not have considered “learning by apprenticeship.”

That’s where systems of neurons gradually favour useful gestures and discard the unhelpful ones.

D’Espagnat finds himself not just rejecting the realists who argue for the “absoluteness” of space and time, but also the idealists who claim Kant pinned down the foundations of the argument.

Not just evolution but also quantum physics was lacking in Kant’s approach, yet even today philosophers consider a “demonstrated truth” the view that spatiality is just the mind’s way of framing phenomena.

Modern physics shows that concepts of Euclidean space, universal time, and precise localization are misleading, even if we need those concepts to operate as humans in our ordinary macroscopic lives.

Kant’s vs Quantum Theory’s Objective Language
In any event, Kant sees science as addressing phenomena, so his version of science is “weakly objective.” So is quantum physics, which speaks of experimental setups and predictions of experimental observations.

But Kant uses the language of objective reality with little modification, while quantum physics uses terms such as electrons and virtual particles for reasons of reluctant convenience.

Kant vs his Followers
Kant’s followers became much more hostile to the idea of an objective reality. Kant talked about the “thing-in-itself,” even if inaccessible to science directly. But neo-Kantians rejected the notion except as a “limiting concept.”

D’Espagnat looks at Ernst Cassirer, a neo-Kantian writing around a century ago. D’Espagnat says he may be the “clearest” of all the neo-Kantians.

Cassirer’s Concept of Concepts vs Traditional Concepts
Cassirer was very interested in the process of coming up with concepts.

He noted that traditionally a big concept contains little information because so many distinctions get blurred.

For instance, we can move from an oak to a tree to a plant to a living being, a concept so broad we hardly have words to describe it.

But with mathematics the bigger categories combine all the qualities of the smaller categories that feed into it.

For instance, the concept of second-degree curves doesn’t mean we can’t tell a circle from an ellipse any more. We just have to plug the right values into the right parameters and we can get a circle.

Logical Necessity vs Quantum Results
Cassirer tries to describe science as a mathematical approach incorporating more and more concepts through some sort of logical necessity.

Reason and the universal scope of logical necessity form the basis for some sort of Being.

But d’Espagnat says that’s just an analogy. If we look directly at quantum physics we see it doesn’t link disparate impressions into some sort of logically and causally required arrangement of entities.

Cassirer’s views on the rules of knowledge and logical necessity put great emphasis on our mental powers to create order rather than some reality “out there.”

Yet d’Espagnat reminds us that experiments often refute one theory or other, so there is something “out there” that can derail some view and just say “no.”

Complete vs Ongoing Pursuit of Knowledge
Furthermore, d’Espagnat’s concept of a “veiled reality” won’t leave us exasperated and depressed, he says, because we will always be able to come up with better and better ways to deal to generalize about phenomena.

Mind-independent Reality vs Internal Consistency
D’Espagnat says some modern philosophers with “Kantian or empiricist inclinations” are less resistant to the idea of an independent reality than Cassirer was.

D’Espagnat says that Hilary Putnam’s “internal realism” sees descriptions evaluated by some kind of “ideal coherence” that keeps our beliefs consistent with each other and with experiences represented in those belief systems.

But d’Espagnat says Abner Shimony thinks Putnam gives up too easily in rejecting any kind of correspondence between our senses and a “mind-independent or discourse-independent ‘state of affairs.'”

Shimony and d’Espagnat think the concept of a “protomentality” has some similarity with quantum mechanical concepts.

Bas van Fraasen came up with a “constructive empiricism” that rejected scientific realism. He said it might be useful to consider structures and processes not directly accessible to an observer, but they’ll have no intrinsic reality.

On the other hand, Fraasen said the issue of what is observable and what isn’t should be left to science not philosophy: the “Grand Reversal.”

Empiricism vs a Knowing Subject
But can Fraasen stay an empiricist when he’s making use of a “knowing subject”?

Shimony thinks empiricism needs to be dropped for some kind of realism — with a strong mental component.

In the end d’Espagnat agrees with Shimony that there must be some way to “close the circle” even if there is a “dark cloud” making the project difficult.

That dark cloud is the impossibility of considering quantum states to have an ontological status.

D’Espagnat says that as long as contemporary philosophers stick to philosophy they have trouble radically casting doubt on veiled reality, or even realism in general.

Only when modern physics is considered do we see how impossible it is to be a conventional realist.

Background image: NASA/JPL-Caltech/P. N. Appleton (SSC-Caltech) via galex.caltech.edu.

Terms of Ontological Endearment

25 August 2011

Mosaic of Reality

Material Witness
In chapter twelve of his On Physics and Philosophy Bernard d’Espagnat tackles three kinds of materialism: dialectical materialism (briefly), “scientific” materialism, and what he calls “neomaterialism.”

Ultimately… ultimate reality isn’t the same as “empirical” or “epistemological” reality, something materialists just don’t get.

At least that’s what he says, and I largely agree.

Here’s my summary of the chapter.

Dialectical Materialism vs Bohr
D’Espagnat says he’s not going to do a detailed analysis of dialectical materialism. He says it’s been sufficiently dismantled elsewhere. However, he warns against seeing too many parallels between Neils Bohr’s approach and this form of materialism.

Bohr’s thought and dialectics may share some general features, but that’s different from dialectical materialism. Bohr had a “human-centred” approach, which could be called materialism only if you radically changed the meaning of the word.

Scientific Materialism vs Atomism
D’Espagnat says “materialism” or “mechanism” doesn’t automatically refer to atomism. Descartes didn’t believe in atoms, and even in the 19th century ether and fields lay outside the realm of the atom.

Macroman on the Street vs the Microworld
The man on the street and even many scientists (particularly in the softer sciences such as biology) think of nature as composed of smaller and smaller grains or specks, eventually leading to atoms. This microworld has (roughly) the same nature as the macroscopic world we experience.

The problem with that idea is that standard quantum theory and the experimental results used to test it show conclusively that atoms, particles, and the forces emanating from them just aren’t like the world at large (as we experience it). This material reductionism doesn’t work.

Standard vs Non-standard Interpretations
Penrose (calling himself a physicalist) adds gravitational effects to the Schrödinger equation. Sokal and Bricmont rely on Broglie–Bohm. However, the first choice is more a research program than a fully fledged theory, and the second choice runs into some trouble with relativity.

The Sokal and Bricmont approach combines corpuscles with nonlocal entities or forces that have the same strength whatever the distance. This isn’t your grandmother’s materialism.

Empirical Reality vs Materialist Reality
Standard quantum mechanics rejects both approaches. At best these materialist approaches describe some “empirical” or “epistemological” reality, a product of how our “mind structure” divides and categorizes reality.

Positivism vs Materialism
Some materialist apologists say quantum mechanics is a product of its times: the 1920s, when positivism (and its emphasis on observation rather than underlying reality) reigned.

D’Espagnat rejects that objection. He says that whatever the origins of quantum theory, rival interpretations still need to be bolstered by evidence.

Research vs Traditions of Research
Michel Bibol and Larry Laudan offer subtler challenges by examining the higher-level assumptions that scientists use. Laudan calls them “traditions of research,” which Bitbol calls “values.” They’re what imparts meaning to a scientific quest.

Observations vs “Ampliative” Arguments
D’Espagnat acknowledges that when mainstream physicists reject Broglie–Bohm because its concepts are unnecessarily complicated or because “action at a distance” messes with relativity they are using “ampliative” arguments.

These are arguments that go beyond what the observations are telling us. After all, physicists could reject the relativity principle as long as they come up with some theory that uses other principles, but acts as if the relativity principle still works.

Bohm vs Materialism
However, even David Bohm rejected materialism. He first spoke of a wave function then later a quantum potential. Neither is localized, hardly what a conventional materialist would call real.

Although Bohm found a way to explain physics without specifying consciousness, he also noted that quantum physics suggests a “mental pole” exists.

Sophistication vs Atomic Materialism
Adding sophistication to atomic materialism doesn’t rescue it. Rather, its “atomism” disappears and its materialism looks increasingly doubtful.

Neomaterialism vs Matter
A third approach to materialism comes from André Comte-Sponville.

He acknowledges nonseparability, a concept that other materialists ignore. D’Espagnat calls this approach “neomaterialism.”

Comte-Sponville gets himself into definitional circles trying to define “matter.” It’s supposed to be everything (but a vacuum), yet also produces the mind. However, if thoughts are real then they’d already be part of “matter.”

Neutral vs Suggestive Terms
D’Espagnat also criticizes Comte-Sponville for using “image-carrying words” such as “matter.” D’Espagnat notes that he himself doesn’t use “matter,” “God,” or “spirit.” Rather he tries to use neutral terms such as “mind-independent reality.”

Nonseparability vs Neomaterialism
Comte-Sponville says the primary question is whether matter is idealist or spiritualist on the one side, or of a physical nature similar to what we experience on the macroscopic level. He’s not an idealist or spiritualist, so he clearly believes in a physical reality.

But as with scientific materialism the idea that reality bears any resemblance to our macroscopic experiences is blown out of the water by quantum physics.

Nonseparability—which Comte-Sponville says is a “mystery”—is an issue whatever theory you choose. It ensures that “ultimate reality” is nothing like our everyday experiences.

Utility vs Evidence
Comte-Sponville eventually acknowledges that if matter includes thought then matter can’t be defined as everything except thought.

However, he says that ultimately what the “natural sciences” say is less important than neomaterialism’s purpose: to explain mind from concepts other than mind, and to do all this to “defeat religion, superstition and illusion.”

D’Espagnat says this argument about the usefulness of neomaterialism just ends up being a circular argument. Deeply held convictions are not themselves an argument.

Empirical vs Ultimate Reality
Ontologically interpretable theories are not consistent with experiment. D’Espagnat says particles and their attributes have a well-defined existence only in relation to knowledge, hence the mind.

Our knowledge of particles and other micro-objects are just that: a kind of knowledge, hence pointing to elements of an empirical, not ultimate, reality.

D’Espagnat says that he and Comte-Sponville both agree that “existence” comes before “knowledge.” But d’Espagnat says mind comes from an “independent reality” not “empirical reality.”

This a materialism does not make.

Convenient Ontologies vs Creeds
Back to materialism in general, d’Espagnat agrees it’s a “tradition of research” as Laudan might put it.

These traditions use values that neither explain nor predict. They are not testable.

These research traditions may include contradictory theories under their umbrella. But some scientists attach a lot of meaning to this identity, and aren’t likely to give up on the term “materialism.”

On a day-to-day basis physicists are using and abusing terms from classical physics such as “particles.” Since physicists would find it hard to move ahead just pondering observations and equations, these concepts are convenient components of a “fabricated ontology.”

D’Espagnat warns these scientists that relying on this ontology to support their rationality may be useful from a practical point of view. Just don’t convert that choice into “an illegitimate doctrinal creed.”

Knowledge of Good and Banal

10 August 2011

Knowledge of Good and Banal

Philosopher’s Walk
A little past the halfway point in Bernard d’Espagnat’s On Physics and Philosophy he switches from a look at the relevance of physics to philosophy to the relevance of philosophy to physics.

If the first chapter of part two, chapter eleven, is any indication, the last half of the book should be a much easier read than the first, though perhaps less satisfying.

It was a huge challenge to wade through d’Espagnat’s descriptions of quantum theory and interpretation, hence I felt the need to write (and post) lots of notes to help me out. At least I felt a sense of reward whenever I finally grasped something of the physics.

But as far as I can tell I agree with d’Espgant’s philosophy anyway. Part two may make easier reading, but I already felt a lot of the modern philosophy, soft sciences, and cultural studies he critiques was just plain hokum. I don’t need more convincing.

In any event, I will trudge on, and I expect I’ll be posting updates to my dualistic summary much more often now.

Science vs Philosophy
Descartes, Pascal, and Leibniz were brilliant scientists and philosophers, but by the eighteenth century a huge breach developed.

Nature of Things vs Behaviour
Fourier refused to speculate on the nature of heat. Instead his heat propagation equation quantitatively predicted heat’s behaviour.

Intuitive vs Unintuitive Notions
Specialization works when concepts such as (in Fourier’s time) “hotter” and “colder” seem obvious, so don’t need to be defined by a theory.

But what’s a quantum field or space-time metrics? Then we do need to consider the nature of such concepts.

Ontology vs Operationalism
The physicist can give up his exclusive interest in behaviours, or can decide that “behaviour” is just a series of recorded observations.

The first option sounds like philosophy, while the second gets close to operationalism.

Physics-Aware Philosophy vs Philosophy-Aware Physics
In first part of his book d’Espagnat called on philosophers to pay attention to the physics. In this second part he calls on physicists to pay attention to the philosophy.

Epistemology vs Scientific Knowledge
D’Espagnat says epistemology, the philosophy of knowledge, is particularly important when considering scientific knowledge.

Logical Positivists vs Modern Sceptics
Epistemology forty years ago was dominated by logical positivists. Nowadays there’s more diversity.

Present-day epistemologists often combine extreme scepticism toward science with an “everything goes” attitude to knowledge in general.

They also talk of “paradigms” in a way that suggests an underlying belief in objectivist realism.

Stubborn Epistemologists vs Blasé Physicists
Physics has moved far, far away from realist attitudes to experimental data. Epistemologists generally ignore two points physicists find obvious.

The first is that equations, such as Maxwell’s, show remarkable power and longevity, even if interpretations of those equations have changed.

The second is that with the help of these equations physical science gets better and better at predicting phenomena.

Paradigm Change vs Continuous Change
D’Espagnat finds fault with much of contemporary epistemology, but he says Thomas Kuhn and others usefully pointed out that science doesn’t always change slowly but surely.

Kuhn sees a strong sociological basis in “paradigm changes”: it’s easier to cast doubt on the present “received” theory than to prove its replacement.

Therefore advocates of change must use more tools of persuasion than just the data.

Experimental Choice vs Outcome
D’Espagnat appreciates that funding and fashion might influence choice of experiment, but he strongly doubts that they affect the results of those experiments.

Short-Term Chaos vs Long-Term Progress
D’Espagnat says epistemologists probably act like historians, seeing short-term upheaval during science’s most productive periods.

But in the long term d’Espagnat strongly believes the “winner” theory will explain not just new facts, but the old ones the previous theory took care of.

Huygens’ Waves vs Newton’s Corpuscles
D’Espagnat acknowledges how Newton’s corpuscular theory of light replaced Huygens’ wave theory even though Huygens’ explained double refraction a lot better.

Does that mean explanatory power is sometimes lost as science “progresses”?

D’Espagnat emphasizes that today’s theory of light is quantum electrodynamics, which improves upon both Newton’s and Huygens’ theories.

Universal Physics vs The Rest of Science
D’Espagnat says epistemologists might dispute the universality of this argument. Instead of physics maybe their claims apply to some other sciences.

He believes in the universality of science in principle, but he admits maybe sciences less dependent on technology may suffer a loss of craft as one theory replaces another.

However, d’Espagnat still believes such a loss would be temporary. Epistemologists again confuse loss of predictive power and a (temporary) lack of interest in some field.

Paradigms vs Reality
Kuhn-like epistemologists are so fixed on objectivist or constructivist realism that they see a change in concepts as a radical change in physics’ view of reality.

As a result some epistemologists speak of the “noncumulative” nature of physics.

Allegory vs Equations
D’Espagnat points to the remarkable stability of equations despite changes in “wordings and outward interpretations.”

A change in concepts doesn’t destroy the old theory, it just generalizes it and provides a new allegorical picture.

Kuhnian vs Other Viewpoints
D’Espagnat notes that in the past fifty years other approaches to scientific knowledge have developed that don’t rely on Kuhn.

Professional Language vs Sloppy Thinking
D’Espagnat says most professional languages help prevent misleading shifts in meaning, but philosophical language actually encourages it.

If you apply critical thinking to philosophical texts you’ll often discover ambiguous meaning and mannered style replacing sound arguments.

Context vs Scientific Purpose
D’Espagnat says some epistemologists delve deeply into the psychology or sociology of scientific discovery, yet remain near silent about what science is really concerned with.

Ideas vs Evidence
Jean-Jacques Rousseau decided humans are good by nature, but forgot this was an idea of his not a piece of evidence.

D’Espagnat says many philosophers of science act the same way, clinging to an idea that is ultimately just part of their dogma.

Empiricists decided a priori that evidence comes from the senses, while positivists have their verification principle.

Relativity vs Quantum Theory
Epistemologists have started taking into account relativity theory but don’t realize how damaging quantum theory is to some of their views.

Positivists vs Realists
Some realist epistemologists speak of entities as having an unconditional individual existence, or naturally assume that particles travel on continuous trajectories.

Realists point to positivism’s failings on philosophical grounds, but the physics points to the failings of realism.

Science vs Cultural Fashion
Some epistemologists think the positivism of the 1920s led to the “weak” objectivity of standard quantum theory, while today’s attitudes are friendlier towards realism.

D’Espagnat calls this argument “valueless.”

If it were just an issue of social psychology and today’s fashion then physicists should now have solved the quantum interpretation problem.

However, as he’s already explained in detail, other quantum interpretations that make the right predictions cannot be interpreted ontologically, and vice versa.

Language vs Thought
Throughout the twentieth century many philosophers paid attention to language, thinking it had to mirror—even mould—the logic of thought.

The problem is various languages have very different structures. Do we think if a group speaks a different language it thinks differently?

D’Espagnat believes “language creates thought” is a Rousseau-like assumption. Aristotle came up with the concept of potentia not so he could think in a new way, but to accommodate new data.

New language is convenient and helpful, but springs from a need to explain new evidence.

Quantum vs Classic Logic
Quantum theory muddies the distinction between concepts of objects and predicates.

Some people have put forward a quantum logic to remedy that situation, but this new logic isn’t a necessary part of quantum theory.

Metalogic vs Specific Rules
D’Espagnat believes that the metalogic used to speak about logic is a universal logic, while specific thinking rules might apply to specific situations.

He notes with approval Bohr’s “basic truth” that everyday language is the only clear means of communication that we have.

Sociologism vs Science
D’Espagnat condemns the idea that “anthropological situations” determine scientific results.

He asks, for instance, if the Heisenberg uncertainty principle would have failed had German and Danish culture been different.

He says this is sheer absurdity and calls the attitude “sociologism.”

Sokal the Anti-Sociologist vs Sokal the Realist
D’Espagnat applauds physicist Alan Sokal’s exposé of sociologists’ fuzzy thinking (by submitting an incoherent, jargon-filled paper to a humanities journal).

However, d’Espagnat regrets how Sokal “drifted to the other extreme” by clinging to physical realism.

Certainties vs The End of Certainties
D’Espagnat disagrees with the phrase “the end of certainties,” which is often used to describe the loss of certain knowledge in modern times.

He rejects this idea, whether it refers to challenges to determinism or physical realism.

Predictive rules, whether of events or probabilities of events, do work. Once experimentally verified they keep on working.

D’Espagnat thinks this is “certain” knowledge, though he agrees that “illusively simple” certainties may prove deceptive and short-lived.

So Say We All

28 June 2011

Quantum States of Confusion
The weeks or months between entries do not reflect a lack of desire to post, or to read, or to learn. I’ve just found Bernard d’Espagnat’s On Physics and Philosophy a tough slog.

His rather involved prose and the often bewildering translation combine to produce some very indecipherable moments, and my merely rudimentary understanding of quantum theory doesn’t help much either.

Here’s the latest of my chapter summaries, presented in the black-and-white dichotomous style that seems to match my thinking. Things are looking up, though, as he’s now getting into more philosophical territory.

Up to now he’s spent a lot of time justifying his interpretations by reviewing the experimental evidence and pointing out flaws in other approaches to the physics. It’s all perfectly legitimate, but as a lay reader I don’t always feel competent to judge who’s right.

So here’s a look at chapter ten of Bernard d’Espagnat’s On Physics and Philosophy.

Laws of Classical Physics vs Quantum Physics
D’Espagnat says that the laws of classical physics were “objectively interpretable” while in quantum physics the laws merely predict observations and the mutual agreement of observers.

Prediction vs Justification
D’Espagnat says modern physics prefers to come up with laws to explain patterns of observation rather than explain what’s “objectively” going on. Even so, can we justify why we choose these rules and why they work?

Quantum Laws vs Macroscopic Predictions
Quantum laws lead to paradoxes such as the Schrödinger cat, not observed in real life. Can we justify the laws behind these paradoxes?

Quantum Laws vs The Alternatives
But more generally, how do we justify (as in “explain”) that these laws work better than any others we might invent?

Ensembles vs Individual Observations
In chapter eight d’Espagnat tackled the “and-or” problem: quantum laws seem to suggest the mixing of two quantum states (aA + bB) whereas our world looks classical (either we detect aA or we detect bB).

Decoherence theory shows how observing a whole ensemble of cats will show each one is either dead or alive in the proportions quantum mechanics predicts. Quantum laws are thus reconciled with observation—except that we generally observe individual cats not ensembles of them.

Mere Predictions vs Hidden Variables
If quantum mechanics merely predicts observations rather than says anything about the “reality” behind what we see then simultaneous states are just a way of calculating probabilities.

On the other hand, Broglie-Bohm’s pilot wave (see chapter two) has a particular probability of being in one of two regions—really being in one of two regions (equivalent to aA or bB).

Standard quantum mechanics says whatever the “Real” happens to be is what produces results that match quantum predictions. The pilot wave approach gets more ontological and suggests what the “Real” must look like to produce those observations.

The two approaches are compatible, though that doesn’t solve various problems with the hidden variable approach (as d’Espagnat has already pointed out).

Outside vs Inside Observations
D’Espagnat then moves beyond our vaguely disembodied, collective observations of instrument pointers, which is what decoherence theory can explain.

He ponders conscious beings that can make predictions about themselves—making observations from within.

Consciousness vs Matter
D’Espagnat says both scientists and “the enlightened general public” look upon states of consciousness as states of matter.

Matter vs Sense Data
D’Espagnat says equating consciousness and matter is hasty, as the argument depends not on the concept of matter but rather on the concept of awareness, as in “registering sense data.”

Sense Data vs Reality
D’Espagnat says Berkeley, Kant, and the neo-Kantians followed the “great principle” that things take place “as if” our senses and classical physics give a true picture of reality.

In other words, the belief was that our sense data give us “an access to ontology.” However, quantum mechanics makes it clear that this principle is a faulty assumption.

Schrödinger’s Cat vs Wigner’s Friend
D’Espagnat says Schrödinger’s cat presumably has a viewpoint on whether it’s alive or not.

Furthermore, Wigner suggested substituting a human. Can we still justify quantum predictions?

Can quantum mechanics agree that an outside observer and “Wigner’s friend” have states of consciousness at the same time?

Improper vs Proper Mixtures
A “proper” mixture of quantum states would be just like a classical sum of states, typically seen in the ordinary macroscopic world.

An “improper” mixture (or “pure case”) is typically seen in entangled quantum systems more or less undisturbed by the outside environment.

The kind of mixture can be determined by measuring a large number (“ensemble”) of identical systems and seeing which states are observed.

Pointers vs Bacteria
Let’s imagine an electron is in the state c = a+b. Some bacteria come along, creating a large number of electron-bacteria quantum systems.

This microscopic electron-bacteria ensemble should be an improper mixture of states aA and bB.

But a problem arises if definite states of consciousness imply definite states of matter.

If the bacteria have states of consciousness then they would be aware if they’re in state A or state B.

The bacteria’s (supposed) self-awareness implies a proper mixture of quantum states, but orthodox quantum theory says there should be an improper mixture.

If orthodox quantum theory holds true then our “conscious” bacterium will lack any power to make predictions.

Pilot Waves vs Schrödinger Wave Function
In the Broglie-Bohm model the “total wave function” doesn’t “collapse” or get “reduced.”

The Schrödinger wave function just gives the probability that the (unorthodox) pilot wave is in some region of the system. No contradiction.

But in orthodox quantum theory the quantum state of the bacterium is an improper mixture of various states, so we get an apparent contradiction.

Microscopic vs Macroscopic Subjects
Bacteria are microscopic but humans are macroscopic. Decoherence theory kicks in, so in practice we can consider electron-human systems to be a proper mixture of two reduced wave functions. Therefore in practice their state of consciousness has predictive power.

Predictive Consciousness vs Predictive Science
D’Espagnat says he’ll explore notions of consciousness in chapter 18, but says the “scientific” definition of consciousness is limited to one of predictive power, and that’s because science itself limits itself to predictive power.

Predictive vs Non-predictive Consciousness
The bacterium or Schrödinger’s cat who thinks it’s alive cannot influence the outside observer if this state of consciousness is non-predictive, says d’Espagnat.

If you could somehow ask the bacteria what their state had been you’d find the results were the same as for a proper mixture.

But we’d assumed the quantum ensemble was initially a pure case (in other words, in an improper mixture).

Asking a question is like taking a measurement. It disturbs the system. Hence no contradiction.

Group vs Individual Observations
D’Espagnat says the generalized Born rule is “impersonal.” It makes predictions about the correlations among observers not what a particular individual observer will see.

So “Aspect-type” experiments measure correlations among observers, whose states of consciousness are correlated (because they’re observing correlated readings).

But if the Born rule is applied to individual observers this correlation would be cut.

D’Espagnat is not comfortable with the “quite inordinate strangeness” that private states of consciousness would differ in this situation, and hence be deprived of some of their predictive power.

He does not, however, rule out this possibility.

Individual vs Group Observations
Although in theory the overall wave function must be the basis for predictions, in practice decoherence lets macroscopic observers rely on their own states of consciousness to make predictions.

Can this reliability of individual predictions be extended to group predictions?

Two friends are looking at the same pointer. By the conventional Born rule they will get the same “impression” of the pointer and hence build up the same kind of wave function to make future predictions.

The different waves that correspond to different impressions of the pointer mostly don’t overlap. That fact and decoherence assure us that the two friends’ predictions will coincide too.

Physics vs Philosophy
D’Espagnat notes a “turning point” in the book. He feels he’s shown the amazing predictive powers of quantum mechanics and its universality. Now he wants to explain why these rules work and where they came from. This takes him further into philosophical territory.

Instrumentalists vs the Kantians
D’Espagnat says the “diehard instrumentalists” think such questions are meaningless, while those sympathetic to a Kantian viewpoint think some explanations are in order but would be found “within the human realm.”

Naive Realism vs Open Realism
D’Espagnat looks for an explanation he calls “open realism.” He believes an explanation can acknowledge “what truly exists” without descending into a simplistic “naive realism.”

Paying attention to the physics dissuades one’s outlook from becoming too naive, he says.

Scientists vs Philosophers
D’Espagnat says most scientists point to the obvious, common-sense appeal of some kind of objective reality.

Philosophers who lean to Kantianism or radical idealism feel there are no “objects-per-se.” We build up a representation of the world using our senses and intellect.

Most scientists say our body of knowledge has increased immensely since Kant’s time, which they say makes obsolete his reasons for doubting human knowledge as a reliable account of what’s out there.

Most philosophers would say Kant wasn’t daring enough. They say he should have rejected the very idea of a “reality-per-se.”

Kant vs d’Espagnat
D’Espagnat agrees that Kant’s arguments were faulty, though justified at the time considering he knew nothing of evolution or mathematical physics.

However, updated arguments lead to a conclusion roughly similar: science doesn’t seek knowledge of “the Real” but rather just of phenomena.

This is not a rejection of some human-independent reality. In this d’Espagnat agrees with Plato and Kant.

Empirical vs Objective Reality
D’Espagnat does not believe physics describes an objective reality. Rather, it describes at most some kind of “empirical reality.”

He is, though, impressed by the consistent nature of Maxwell’s equations and other major laws, leading him to think physics provides “some not altogether misleading glimpses” of the underlying structure of reality.

“The Real” vs Phenomena
D’Espagnat puts out there the idea of an “extended causality” in which “the Real” imparts some kind of non-quantitative influence on phenomena. He adds that this is just a supposition of his.

Unreachable vs Veiled Reality
D’Espagnat does not believe “the Real” is “radically unreachable.” Rather, it is “merely veiled.”

He emphasizes that this doesn’t mean there’s even a “vague similarity” between our perceptions of reality and what’s behind the veil.

“The Real” vs Space-time
Bell’s theorem and Aspect’s experiments (among others) connect space-time with nonlocality. D’Espagnat hence doesn’t think “the Real” lies in space-time.

Mirroring Kant, d’Espagnat believes space-time is not “noumenal.” It’s just a “reality-for-us,” hence “phenomenal.”

D’Espagnat vs Mohrhoff
Another approach comes from Ulrich Mohrhoff. He thinks some aspects of phenomenal space may be considered strongly objective as long as other aspects are discarded. He suggests that physical space does not intrinsically exist independent of the objects that are in them.

In a footnote d’Espagnat says the suggestion “is certainly worth studying.”

D’Espagnat vs Modern Philosophers
Compared to his disagreement with science’s “physical realists,” d’Espagnat says there’s a “high degree of convergence” between his views and many philosophers.

There’s still some difference of opinion. D’Espagnat believes in a veiled reality while many philosophers think reality is “radically unreachable.”

He also notes that many philosophers feel his “open realism” postulate is arbitrary. D’Espagnat admits it’s unprovable (he does call it a postulate, after all) but feels there are serious arguments to support it.

Existence vs Knowledge
D’Espagnat’s first argument for his postulate is that “existence” comes before “knowledge.”

He admits that the existence of a particular something may logically depend on the possibility of our knowing it.

However, he agrees with Plato and Kant that the very notion of existence can’t depend on our possible knowledge of this existence.

Beautiful Theories vs Falsifiability
D’Espagnat’s second argument for his postulate is that beautiful, consistent theories can be struck down by experiment. Theories predict consequences that can be contradicted by observations.

We can’t be totally in control of what we perceive or not.  In d’Espagnat’s words: Something says “no.”

Realism of the Accidents vs External Influence
D’Espagnat’s third argument for his postulate refers back to chapter five’s “no-miracle” and “intersubjective agreement” arguments.

He says they do not support realism of the accidents or anything close to it. However, they do show, in his opinion, that physical laws depend at least partly on something that is not “us.”

Present vs Past Building Blocks of Knowledge
D’Espagnat’s fourth argument for his postulate is that a priori concepts of human knowledge change over time. Kant could rely on Euclidean space, universal time, and determinism to reject reality-per-se as the source of such concepts.

Nowadays science’s building blocks include curved space, space-time, and indeterminism. It’s hard to believe that we can rely on these basic concepts of human knowledge when they keep changing.

Also, Kant’s building blocks were very intuitive. Physics today uses unintuitive concepts that are so unintuitive it’s hard to believe they sprung from some innate concepts we hold.

So we’re left with either physical realism or contenting ourselves with science as prediction.

Physical realism has (in d’Espagnat’s view) been thoroughly demolished, leaving just the empirical/predictive option—with the caveat that there’s something out there that prevents us from being entirely arbitrary in our perception of reality.

Partial Knowledge vs Veiled Reality
D’Espagnat also mentions some misunderstandings he feels others have of his work.

He says Roland Omnès takes his concept of veiled reality and calls it some kind of “weak realism” in which only partial knowledge of reality is possible.

D’Espagnat says he never uses the term “weak realism,” and thinks Omnès doesn’t appreciate the huge jump from “independent reality” to “empirical reality.”

Veiled reality is no more partially knowable than Kant’s phenomena “are knowable bits of noumena.”

D’Espagnat repeats, though, that the mathematics of some physical laws may “vaguely resemble” some of the “great structures of ‘the Real.’”

D’Espagnat vs Esotericism
Although d’Espagnat says he’s mostly disappointed with the “esoteric visions” that have pointed to his writings, although there are some “intermediate cases.”

D’Espagnat appreciates Thierry Magnin’s approach to “levels of reality” but feels he got it wrong when he sees veiled reality related to “unpredictability and chaos,” the “constructive role” of time, and science as a social construct.

D’Espagnat does note that he’ll explore the objectivity of science in the next chapter, but his concept of veiled reality does not spring from that issue.

Veiled Reality vs Anomalous Phenomena
D’Espagnat says it’s understandable that the views of anyone not agreeing with a “mechanistic conception of nature” would be used to explain various “phenomena seemingly defying the laws of science.”

However, d’Espagnat believes nonlocality in no way explains supposed influences at a distance.

Neither does d’Espagnat doubt the “robustness of the physical laws,” but rather believes them likely to be “correct and universal.”

Finally, the concept of veiled reality addresses a philosophical understanding of reality, not the particulars of observed phenomena.