Sunday, 7 August 2022

Scientific Theories Don’t Need To Be True

The philosopher Ernan McMullin didn’t believe that the “acceptance of a scientific theory [also] involves the belief that it is true”. Moreover, “to suppose that a theory is literally true would imply that no further anomaly could arise”. And surely such a stance on truth is counterproductive in science.

The Irish philosopher Ernan McMullin (1924 — 2011) was the O’Hara Professor of Philosophy Emeritus at the University of Notre Dame. He was a philosopher of science who wrote on theology, cosmology, values in science, Darwinism, etc. McMullin was also a Catholic priest and an expert on Galileo.

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Karl Popper (1902–1994) once argued that the notion of truth is counter-productive in science because the attainment of complete truth (even if possible in principle) would bring the (or a) scientific story to an end. Instead, Popper argued for what he called verisimilitude.

[As one source defines verisimilitude: “In philosophy, verisimilitude (or truthlikeness) is the notion that some propositions are closer to being true than other propositions.”)

The main problem here is that it can be argued that the notion of complete truth is actually contained (or embedded) within the notion of verisimilitude. Ernan McMullin (in his ‘A Case for Scientific Realism’) made this point when he wrote that the

term ‘approximate truth’ [] is risky because it immediately invites questions such as: how approximate, and how is the degree of approximation to be measured?”.

In order to know that a theory is approximately true, wouldn’t we also need to know what would make it completely true and/or what makes it partly false? And in order to know both those things, wouldn’t we also need to know what the complete truth of that theory is? Moreover, what is a theory’s approximate truth measured against?

On this critical reading, then, there is no approximate truth or verisimilitude at all.

The Canadian philosopher Ian Hacking (in his book The Social Construction of What?) hints at a similar point when he mentions the positions of Thomas Kuhn and the physicist Steven Weinberg. He writes:

“In Structure Kuhn rejected the idea of scientific progress towards some one final vision of the world. What we see in the history of science is progress away from previous beliefs. Weinberg (1996b, 56) quotes some of Kuhn’s later writing, where Kuhn had said ‘it’s hard to imagine… what the phrase ‘closer to the truth’ can mean.’ [].”

One doesn’t need to be be a Kuhnian to agree that the phrase “closer to the truth” is both problematic and odd. So perhaps it should never be taken literally (i.e., it should be taken poetically or even rhetorically). But, of course, in the cases mentioned in this essay at least, the phrase is taken literally.

Ernan McMullin added to all this when he wrote the following:

I do not think that acceptance of a scientific theory involves the belief that it is true. Science aims at fruitful metaphor and at ever more detailed structure. To suppose that a theory is literally true would imply, among other things, that no further anomaly could, in principle, arise from any quarter in regard to it.”

It can be doubted that McMullin actually knew that no scientist believes that his own and other scientific scientific theories are true. That’s because there are many scientists who have used the word “truth” — if perhaps sometimes loosely — about their own and other scientists’ theories.

So perhaps McMullin’s position was both philosophical and normative. Indeed the normative and logical elements of his position are encapsulated in his final words:

“To suppose that a theory is literally true would imply, among other things, that no further anomaly could, in principle, arise from any quarter in regard to it.”

On another tact. Strictly speaking, only statements can be true or false. Nonetheless, if a theory is simply seen as a collection of true statements, then its entirety can also be seen as being true due to the fact that all the statements it contains are also true…

Yet scientific theories don’t really work like that.

Even though theories do contain statements, not all its statements are either true or false. (Strictly speaking, then, perhaps they aren’t statements at all.) Some statements involve predictions, probabilities, conjectures (or speculations), reference to “unobservables” and whatnot. Only few of the statements (or expressions) which make up most theories will have a purely (as analytic philosophers put it) truth-conditional content.

In addition, it’s also clear that what McMullin referred to as “fruitful metaphor[s]” can’t be true or false either.

What McMullin also seems to have argued is that a “worldly structure” shows itself only slowly — over time. Each successive theory about the (same?) structure comes… well, closer to the truth. (This is the position of scientific structuralism.) However, since this is ongoing process concerning theories about structure x, then no single theory of x can ever be said to be conclusively true.

McMullin then gave an example of a worldly structure.

He stated that “[s]cientists in general accept the quantum theory of radiation”. He then asked: “Do they believe it to be true?” McMullin concludes:

“Scientists are very uncomfortable at this use of the word ‘true’ because it suggests that the theory is definitive in its formulation.”

In other words, scientists don’t need to classify (or even see) their theories as being true. Indeed it can even be said — and it has been said — that scientists don’t need truth at all. Instead, a scientist can “accept an explanation as the best available”. Moreover, “one accepts a theory as a good basis for further research”.

All that said, some readers may detect truth — even complete truth — lurking underneath all these words, arguments and positions.

Thursday, 4 August 2022

Why Richard Feynman (the Superstar Physicist) Hated Philosophy and Philosophers

Richard Feynman called philosophy “low-level baloney” and philosophers “pompous fools” who make “stupid remarks”. He also said that “cocktail-party philosophers never really understand the subtleties and depths” of the problems they tackle.

The well-known American theoretical physicist Richard Feynman (1918–1988) didn’t like philosophy. He particularly didn’t like philosophers. Indeed Feynman is so renowned for his dislike of philosophy and philosophers that the UK’s very own physicist and media personality Brian Cox couldn’t stop himself from mentioning Feynman’s very-often-quoted remark that

“the philosophy of science is as useful to scientists as ornithology is to birds”.

Ironically enough, Brian Cox also once tweeted a comment (see here) about a Feynman quote which had previously been taken to mean (at least on Twitter) that scientists should “stick to science” — i.e., rather than discuss ethics, Donald Trump/Joe Biden, Brexit, the Ukraine, Jeremy Corbyn, films, fate, peace, social justice, the Internet, people’s sex lives, “the future of humanity” (or “the world in 2030”), UFOs, déjà vu… and also, perhaps, philosophy itself. (See my ‘Michio Kaku and Other Superstar Physicists on the Price of Bread’.) Clearly Feynman didn’t follow his own rule because he often ventured outside of science with his (published and broadcast ) opinions… not least when commenting on philosophy and philosophers. (Hence the many social-media memes of Feynman’s words.)

Of course, as a loyal member of the Tribe of Physicists, Brian Cox claims that “[t]his Feynman quote is regularly taken out of context”. In other words, Cox believes that scientists should comment on politics and on (all?) other subjects too.

[I’m assuming — because it’s unclear from the Twitter thread — that the words “stick to science” had been aimed at Brian Cox because he often comments on issues which have nothing at all to do with science… Unless, that is, literally everything has something to do with science.]

To return to Feynman on philosophy and philosophers.

Feynman called philosophy “low-level baloney”. (What, exactly, is high-level baloney?) What’s more, he claimed that philosophers make “stupid remarks”.

Like many other physicists, Feynman’s big problem was that philosophy isn’t physics. His other big problem was that philosophers aren’t physicists. Those two statements together may seem like a crude and simplistic account of Feynman’s actual position. However, if you read his words, you’ll quickly note the lack of names of actual philosophers or any details about what they actually wrote or said.

[This state of affairs was replicated by the German theoretical physicist and YouTube presenter Sabine Hossenfelder. For example, she wrote an article (called ‘Electrons Don’t Think’) on the philosophical position of panpsychism. In that article she doesn’t quote a single panpsychist, tackle a single argument in support of panpsychism or even paraphrase a single panpsychist’s words. See my ‘Sabine Hossenfelder Doesn’t Think… About Panpsychism’.]

So now take Feynman’s claim that philosophers “never really understand the subtleties and depths of the problem”. Ironically, it’s worth noting here that Feynman himself once uttered the following (also) often-quoted soundbite:

“I think I can safely say that no one understands quantum mechanics.”

To be honest, I find Feynman’s remark purely rhetorical. After all, it’s fairly clear that Feynman didn’t have too much time for the interpretations of quantum mechanics — let alone for the philosophy of quantum mechanics. (Perhaps more accurately, Feynman didn’t publish anything on the interpretations of quantum mechanics. There are, however, papers such as ‘Feynman’s interpretation of quantum theory’.) In other words, Feynman knew all of the relevant mathematics. “The trouble was”, as science writer Philip Ball (1962-) puts it (in his book Beyond Weird), “that’s all he could do”. What’s more, to Feynman, “[quantum] theory works”; though “without our knowing what it’s about”.

One can guess (i.e., from the overall context) that Feynman’s claims basically mean that (most? all?) philosophers don’t understand the mathematics and all the technical details involved in physics. Or to put it more simply: Feynman was basically saying that philosophers don’t know as much about physics as… physicists (or at least not as much as physicists like him).

In that sense, then, theoretical physicist and cosmologist Stephen Hawking (some 40 or more years later) replicated Feynman’s views when he stated that “philosophers haven’t kept up with physics”. Indeed (in his book The Grand Design) Hawking went into more detail as to what he thought about philosophy in the following passage:

“Traditionally these are questions for philosophy, but philosophy is dead. Philosophy has not kept up with modern developments in science, particularly physics. Scientists have become the bearers of the torch of discovery in our quest for knowledge.”

Yet, of course, if philosophers knew as much about physics as physicists, then they’d probably actually be physicists.

Did Feynman Only Dislike the Philosophy of Science?

Some commentators and readers may say that it was only the philosophy of science (as in “The philosophy of science is as useful to scientists as ornithology is to birds”) that Feynman had a problem with. Indeed Feynman did once say that “what science is, is not what the philosophers have said it is”. (Feynman also went on to say that science is “certainly not what the teacher editions say it is”.)

In that sense, then, Feynman’s position was later replicated by the American theoretical physicist Lawrence Krauss (1954-) when, in an interview with Ross Anderson, he said:

[T]he worst part of philosophy is the philosophy of science; the only people, as far as I can tell, that read work by philosophers of science are other philosophers of science.”

Despite that, Marcus Munafo (a professor of biological psychology) and George Davey Smith (the director of the MRC Integrative Epidemiology Unit at the University of Bristol) have written the following words:

“Richard Feynman once claimed that the ‘philosophy of science is as useful to scientists as ornithology is to birds.’ We disagree.”

Who knows, perhaps Feynman would have picked up on the fact that these two scientists aren’t physicists. That is, biological psychology isn’t physics and epidemiology isn’t physics either. So was Feynman a Sheldon Cooper-type character in that he too had very little respect for any discipline — other than mathematics — that wasn’t theoretical physics? (Shelden Cooper is — or was — a young and “eccentric” theoretical physicist in the American sitcom The Big Bang Theory.)

In any case and as the philosopher-with-a-doctorate-in-physics David Z. Albert (1954-) put it (in a videoed debate):

“What the hell have physicists done for music lately?”

To repeat: when you read Feynman’s words, it’s clear that he had a problem with just about all philosophy.

Various reasons have been cited for Feynman’s antipathy toward philosophy… That is, other than the reason that he couldn’t stomach the fact that philosophy isn’t physics.

For example, according to Stephen Doty, Feynman (as a young student) had a bad experience with none other than René Descartes:

“Descartes basically infers that his idea of a perfect God could only have been caused by a perfect God, who therefore must exist. Descartes overlooked that he could have just as well acquired an idea of God from being taught the word as a child from his religious instruction. He might as well have argued that his idea of a Ideal Woman must have an equal cause, so she must exist too.”

According to the same commentator:

“Second, while in graduate school at Princeton, Feynman sat in on a philosophy lecture. The professor, knowing Feynman was a physics student, asked him if an electron was an ‘essential object’. Feynman asked back whether a brick is an essential object. Some students said yes, but others said that only the concept of a brick or its ‘brickiness’ was. They could not agree, so Feynman never answered the question and left saying philosophers used words in a ‘funny way’.”

And finally:

“Feynman’s most annoying brush with philosophy occurred at an ethics conference. His group was asked to discuss ‘The ethics of inequality in the fragmentation of knowledge.’ Feynman wanted to frame a clear question first, but the others saw no need. They wrote their report in a pretentious academic style which frustrated Feynman, so he decided to translate it into plain English. The first opaque sentence reduced to ‘People read.’ … ‘pompous fools’ in the humanities, as he called them, were intolerable.”

Feynman’s Apt Criticisms of (Some) Philosophy

Not to be entirely one-sided and biased, it’s worth stating that some of Feynman’s criticisms of philosophy are both worthwhile, apt and indeed… philosophical. That said, Feynman’s criticisms of philosophy aren’t original. That is, some of his criticisms of philosophy had already been stated by… philosophers.

Take Feynman’s references to what seems to have been ordinary language philosophy (or, more broadly, linguistic philosophy), which he called “dopey”. In his Lectures on Physics Vol.1 (1963), Feynman wrote:

“We can’t define anything precisely. If we attempt to, we get into that paralysis of thought that comes to philosophers [] one saying to the other: you don’t know what you are talking about! The second one says: what do you mean by ‘talking’? What do you mean by ‘you’? What do you mean by ‘know’?”

One philosopher who’d made these points before Feynman was Karl Popper. (He partly did so in his paper ‘The Nature of Philosophical Problems and Their Roots in Science’, which was published in 1952 — some 11 years before Feynman’s words.) Indeed the reign of linguistic philosophy (if that was Feynman’s true target at all) only lasted around 25 years (roughly, from the 1940s to when Feynman wrote these words in the mid-1960s).

What’s more, it was other philosophers who destroyed this “school” or movement! (Incidentally, other philosophers - such as W.V.O. Quine, Hilary Putnam, Karl Popper, Thomas Kuhn — destroyed logical positivism too. See here.)

One notable critique of ordinary language philosophy can be found in Ernest Gellner’s book Words and Things, which was published in 1959. (Who knows, perhaps this last fact would have proved Feynman’s point too.)

Let’s now go into some detail and tackle the ‘Relativity and the Philosophers’ section of the chapter ‘Relativistic Energy and Momentum’ (which is from The Feynman Lectures on Physics).

Feynman’s ‘Relativity and the Philosophers’

Perhaps it may seem a little unfair to focus on what Feynman said about philosophers. However, in the section ‘Relativity and the Philosophers’ (of a larger chapter) at least, the exclusive theme here is what philosophers believed about Albert Einstein’s Relativity (specifically when it came to motion). In that section Feynman never once mentions the views of laypersons, artists, other scientists, or political activists on this subject. Feynman’s focus was entirely on what philosophers thought about the issue he tackles — namely, what he called “physical relativity”.

As a taster, Dennis Richard Danielson classes this section (of a larger chapter) from Feynman as a “satire” which is

“aimed at those who would reduce physics to either woolly, trivializing ‘philosophy’ or lazy paradox’”.

Cocktail-Party Philosophers

Feynman uses the term “cocktail-party philosophers” throughout the section ‘Relativity and the Philosophers’. I have absolutely no idea who he’s referring to. That’s primarily because Feynman doesn’t mention a single philosopher’s name or actually quote anyone.

In any case, Feynman then stated that he would henceforth call all philosophers who believed “all is relative” (i.e., the ones he didn’t want to “embarrass” in writing) “cocktail-party philosophers”.

Personally, I’ve never come across the phrase “cocktail-party philosophers” and Feynman doesn’t go into much detail about it. (Of course one can easily guess what he meant!) So I Googled the phrase. That didn’t help. All I found were references to Feynman’s own use of these words. So it can only be assumed that the phrase “cocktail-party philosophers” was flying around the place in the early 1960s. Alternatively, perhaps Feynman actually invented the phrase. (That said, he does put the words in scare quotes.)

At first, the way Feynman puts the positions of these cocktail-party philosophers — and what he says about them as people — makes them seem like pretentious (as well as pretty dumb) postmodernists or poststructuralists… The problem with that possibility is that Feynman wrote these words in 1963.

Alternatively, perhaps Feynman didn’t mean real philosophers (whatever they are) — just those people at (cocktail) parties who think they’re philosophers. The problem here, however, is that Feynman did repeatedly attack philosophers and philosophers without ever mentioning cocktail parties. That is, Feynman attacked professional philosophers. Indeed, when you read all this section, it can be seen that Feynman couldn’t possibly have had in mind laypersons philosophising their arses off at parties.

For example, Feynman wrote:

“These philosophers are always with us, struggling in the periphery to try and tell us something, but they never really understand the subtleties and depths of the problem.”

This can’t be a reference to philosophical loudmouths at parties. For a start, have cocktail-party philosophers — specifically — “always [been] with us”?

To be fair to Feynman, he did at times reign in his generalisations about philosophy and philosophers.

For example, Feynman wrote that “there is even a philosophy that one cannot detect any motion except by looking outside”. So at least Feynman writes “there is even a [my italic] philosophy”, rather than, say, “[all] philosophers believe that…”. This implied that there may be a philosophy — lo and behold — that didn’t have this position on motion.

So Feynman, at least here, appears to have accepted the possibility that there was more than one “school” of philosophers.

What’s more, after generalising about philosophers believing that “all is relative”, Feynman does mention what he called “another school of philosophers”. The philosophers in that school (whichever school Feynman actually had in mind) “felt very uncomfortable about he theory of relativity”.

All this means that one school of philosophy (i.e., the Cocktail Party School) embraced the idea that “all is relative” and another school of philosophers… didn’t. This also means that Feynman had a go at one group of philosophers for “feel[ing] very uncomfortable about the theory of relativity”; and then went straight ahead and had a go at another group of philosophers for embracing it.

All is Relative?

Feynman claimed that “a surprisingly large number of philosophers, not only those found at cocktail parties” believed that “Einstein’s theory says all is relative!”.

Had Feynman access to the views of a “large number of philosophers”? He might well have done so. However, he didn’t mention a single one of them. That said, Feynman did also claim that he didn’t want to “embarrass” the philosophers who held this view. In that case, then, why didn’t he simply mention some philosophical movements (or schools), positions, arguments, or philosophical isms instead?

It’s certainly true that at least some philosophers — and more people outside philosophy — did once argue that “all is relative”. The problem for Feynman’s position is that not all philosophers did so. Indeed, if a vote had ever been taken on this subject in 1963 (roughly when Feynman wrote these words), then my bet is that only an extreme minority of philosophers would have argued that all is relative. (This universal claim is vague anyway.)

So perhaps Feynman had such an extreme minority in mind. That said, why didn’t he make that clear and name some names?

Interestingly, the American journalist and author Walter Isaacson (1952-) makes various points which might well have undergirded Feynman’s own position on philosophy and philosophers. Isaacson wrote:

“In both his science and his moral philosophy, Einstein was driven by a quest for certainty and deterministic laws. If his theory of relativity produced ripples that unsettled the realms of morality and culture, this was not caused by what Einstein believed but by how he was popularly interpreted.”

More relevantly, the British historian Paul Johnson (1928-) stresses that it wasn’t (just?) philosophers who’d overstretched Einsteinian Relativity. Johnson wrote:

“At the beginning of the 1920s the belief began to circulate, for the first time at a popular level, that there were no longer any absolutes: of time and space, of good and evil, of knowledge, above all of value. Mistakenly but perhaps inevitably, relativity became confused with relativism.”

Feynman’s own overall position was (of course) that “it is not true that ‘all is relative’”. So if Feynman believed that philosophers held the position that all is relative, then, sure, he’d have had a very good reason to be against philosophers… Except we still have the inconvenient fact that not all philosophers did believe that all is relative.

One other problem Feynman had with the All is Relative School of Philosophers (or Cocktail Party Philosophers) was that they suffered from the malady of stating the bleeding obvious. In one particular example, Feynman basically states that such all-is-relative philosophers needn’t have stolen Einstein’s ideas in order to make their (rather obvious) point. Feynman himself wrote:

“That what one sees depends on his frame of reference is certainly known to anybody who walks around, because he sees an approaching pedestrian first from the front and then from the back; there is nothing deeper in most of the philosophy which is said to have come from the theory of relativity [].”

And many people would agree with all that.

What’s more, agreement will also have come from many of the philosophers who were around when Feynman wrote those words; just as it will come from many — or even most — philosophers who’re around today.



Sunday, 31 July 2022

The Interpretations of Quantum Mechanics are Myths and Analogies

Astrophysicist, astronomer and science writer John Gribbin argues that “all the interpretations of quantum mechanics are myths”. He also states that it’s “hard to see quantum physics as anything but analogy”.

(i) Introduction
(ii) The True Interpretation!
(iii) Scientific Models
(iv) Analogies
(v) All Interpretations are Equal?
(vi) Gribbin’s Faves: The Many-Worlds and Transactional Interpretations

John R. Gribbin (who was born in 1946) is an astrophysicist, astronomer and a science writer. He earned his PhD in astrophysics from the University of Cambridge in 1971.

In 1968, Gribbin worked as one of Fred Hoyle’s research students at the Institute of Theoretical Astronomy. In 1984, Gribbin’s In Search of Schrödinger’s Cat: Quantum Physics and Reality was published: it became a bestseller. (Most of the passages from Gribbin in this essay are actually from his book, Schrödinger's Kittens and the Search For Reality.) The Spectator Book Club described Schrödinger’s Cat one of the best popularisations of physics to precede Stephen Hawking’s A Brief History of Time. The Spectator also described Gribbin as “one of the finest and most prolific writers of popular science around”. In 2009, at the World Conference of Science Journalists, the Association of British Science Writers awarded Gribbin its Lifetime Achievement award.

A list of Gribbin’s papers and articles can be found here — complete with links to the original sources.

Introduction

It can be assumed that even a few laypersons (or beginners) have quickly noted the obvious and strong distinctions which can be made between quantum mechanics (or quantum theory) and its many and various interpretations. (Wikipedia cites 15 “influential interpretations”!) That said, there have been far more laypersons (or beginners) who’ve strongly conflated the interpretations of quantum mechanics with quantum mechanics itself.

So now it can be argued that all the interpretations of quantum mechanics are in the same ballpark for the obvious reason that each one is an … interpretation. This means that the fact that the interpretations are interpretations of the physical data and the mathematics doesn’t really make any difference in this respect. And that’s because all the interpretations — almost by definition — still go beyond the data, mathematics, predictions, experiments, observations and tests.

And it’s — at least partly — because of all the above that John Gribbin takes his radical position on such interpretations.

Gribbin writes:

“You are free to choose whichever of the quantum interpretations most appeals to you, or to reject all of them, or to purchase the entire package and use a different interpretation according to convenience, or the day of the week or whim.”

And, elsewhere, Gribbin adds:

“I stress, again, that all such interpretations are myths, crutches to help us imagine what is going on at the quantum level and to make testable predictions. They are not, any of them, uniquely ‘the truth’; rather, they are all ‘real’, even where they disagree with one another.”

Prima facie, Gribbin’s position seems to be one of scientific relativism. Or, at the very least, one of scientific pluralism. Indeed when Gribbin states that “[r]eality is in very large measure what you want it to be”, he actually seems to be venturing into (a subjective or even solipsistic) idealism.

[Many scientists are pluralists when it comes to scientific theories, concepts and models.]

Alternatively, is all this a scientist’s very own version of some kind of (postmodern?) constructivism or constructionism? (Sure — that’s a hell of a lot of isms!)

Now, despite that last (as it were) charge of constructivism, it’s worth nothing that there’s a chapter called ‘Constructing Quarks’ in Gribbin’s book Schrödinger's Kittens and the Search For Reality (1995). This chapter — and perhaps many of Gribbin’s other words on quantum mechanics — is strongly inspired by the ideas of the sociologist and historian of science Andrew Pickering (1948-) and his book of (almost) the same name, Constructing Quarks: A Sociological History of Particle Physics (1984).

Gribbin even gets all psychological and aesthetic when he concludes (at the end of one of his books) that we “are free to choose whichever one gives you most comfort, and ignore the rest”.

Still, Gribbin immediately concludes the passage above with the following (as it were) acknowledgement:

“Still, though, almost everybody wants to know ‘the answer’. The quest for a really real model is what drives theoretical physicists.”

Gribbin even confesses that he “still had this hankering” for the really real himself — “even though the logical part of [his] mind tells [him] that the search is fruitless”.

But what of scientific pluralism?

Is it automatically a good thing?

Take the physicist David Finkelstein’s words on the problem we (especially laypersons or beginners) have with so many different interpretations of quantum mechanics.

Finkelstein firstly tells us that “[q]uantum theory was split up into dialects” and that this was the case because “[d]ifferent people describe[d] the same experiences in remarkably different languages”. (Finkelstein’s last point is a good expression of the underdetermination of theory by the data thesis.)

Yet that widespread pluralism may still seem to be commendable and even productive… except for the fact that all this is (Finkelstein continues) “confusing even to physicists”.

So there are three (among other) alternatives we (or at least physicists) can take:

(1) Pick a particular interpretation. 
(2)
“Buy the lot” (i.e., “purchase the entire package”) — as John Gribbin suggests.

Or:

(3) Reject the whole lot.

So now take the words of physicist N. David Mermin (1935-), which can be interpreted as a suggestion to “buy” option (3).

Mermin tells us that quantum theory

“is so beautiful and so powerful that it can, in itself, acquire the persuasive character of a complete explanation”.

[It can, of course, be asked what Mermin means by “complete explanation”.]

More broadly, a person who’s against all the interpretations of quantum mechanics can argue that we have no need, right or philosophical justification to interpret the mathematical formalism/s, observations, data, experimental results and tests at all.

It can now be asked if it’s ever possible — even in principle — to completely bypass all interpretation in quantum mechanics. Indeed can we even say what quantum mechanics is (i.e., beyond the mathematics) without relying on at least a degree of interpretation?

So, in that case, we’d need to be specific as to what the interpretation is and what precisely it is that’s being interpreted.

In any case, Gribbin believes that

“none of [the interpretations of quantum mechanics] is anything other than a conceptual model designed to help our understanding of quantum phenomena”.

Gribbin’s primary reason for stating the above is that all the interpretations he considers “make the same predictions”. What’s more, Gribbin refers to John G. Cramer’s position on his own interpretation (i.e., Gribbin’s favoured transactional interpretation — see later) when he writes that

“Cramer is at pains to stress that his interpretation makes no predictions that are different from those of conventional quantum mechanics”.

Now that really does clarify the situation here.

Indeed, if one is very uncharitable, the words above may possibly show us the utter redundancy of all the interpretations of quantum mechanics. (Hence the oft-quoted words “Shut up and calculate!”.)

Of course stating that the many different interpretations of quantum mechanics “make no [unique] predictions” is hardly an original point. Commentators have been stating this since at least the 1950s.

Yet despite all of Gribbin’s words above, he states that many (or even all?) of the interpreters of quantum mechanics believe that their own interpretations are true…

The True Interpretation!

… That’s right — true.

Gribbin writes:

[T]he interpreters and their followers will each tell you that their own favoured interpretation is the one true faith, and all those who follow other faiths are heretics.”

The passage above comes straight after Gribbin had already told us that “[a]t the level of equations, none of these interpretations is better than any other”. And, conversely, that “none of the interpretations is worse than any of the others, mathematically speaking”. (Much of this may hinge on precisely how we’re to take the phrases “at the level of equations” and “mathematically speaking”.)

Gribbin also referred to the book The Ghost in the Atom: A Discussion of the Mysteries of Quantum Physics, which was edited by the physicist and writer Paul Davies. Gribbin claims that in that book “the experts can each be seen solemnly claiming that one particular interpretation is correct while the others are impossible”. Gribbin continues:

“Utterly sure of themselves, and with few exceptions, they all plump for different versions of reality and dismiss the others.”

Theoretical physicist Steven Weinberg (1933–2021) seemed to concur with Gribbin when he wrote the following:

[M]any physicists are satisfied with their own interpretation of quantum mechanics. But different physicists are satisfied with different interpretations.”

Scientific Models

John Gribbin’s position on the interpretations of quantum mechanics is very similar to his position on scientific models. Indeed his position on what models are is fairly standard within science itself.

Gribbin writes:

All models are deliberately simplified, by our choice of which degrees of freedom to use as handles on reality; and all models of the world beyond the reach of our immediate senses are fictions, free inventions of the human mind.”

What Gribbin says is almost — or even literally — true by definition. (The clue is in the word “model” itself.) More relevantly, what Gribbin stated above can be rewritten in this way:

All interpretations of quantum mechanics are deliberately simplified, by our choice of which degrees of freedom to use as handles on reality; and all interpretations of quantum mechanics beyond the reach of our immediate senses are fictions, free inventions of the human mind.

Gribbin also writes:

“All models of the atom are lies in the sense that they do not represent the single, unique truth about atoms; but all models are true, and useful, in so far as they give us a handle on some aspects of the atomic world.”

Here again the above can be rewritten in order to make it apply to the interpretations of quantum mechanics:

All interpretations of quantum mechanics are lies in the sense that they do not represent the single, unique truth about reality; but all interpretations are true, and useful, in so far as they give us a handle on some aspects of the quantum world.

One would hope that Gribbin was being rhetorical and/or poetic when he used the word “lies” about scientific models. (That applies to the words “truth” and “true” too.) Pedantically speaking, a single model can’t be true, a lie or false. That’s because a model isn’t a statement or even a set of statements. So a model can’t literally be a lie; or, strictly speaking, either true or false. It can, however, be accurate, useful, helpful, etc.

As for Gribbin’s words “unique truth”.

In order for a model to be the unique truth about any given x, then it would actually need to be x. (“The best model of the world is the world itself.”)

Gribbin also seems to put a pragmatist position on truth. That is, he associates a model’s truth with its being (what he calls) “useful”. Thus a model is true only if it is useful. (Incidentally, Gribbin says almost exactly the same thing about the interpretations of quantum mechanics.)

Yet this pragmatist and/or pluralist position on models inevitably leads to this question:

What is the model a model of?

Let’s say that it’s a model of a given x, which isn’t itself a model.

Yet what is this x when (as it were) stripped of its (or any) model?

The English theoretical physicist and cosmologist Stephen Hawking (1942–2018) got to grips with that problematic question in the following passage:

“There is no picture- or theory-independent concept of reality. Instead we will adopt a view that we will call model-dependent realism: the idea that a physical theory or world picture is a model (generally of a mathematical nature) and a set of rules that connect the elements of the model to observations. This provides a framework with which to interpret modern science.”

If you can’t picture, describe or even access “reality” without a model (as Hawking suggests in his philosophical position of model-dependent realism), then Gribbin’s pluralism may well have a lot going for it.

So it’s fairly clear that Gribbin pretty much puts the interpretations of quantum mechanics in the same — or at least a similar — box as models in science generally.

So what about analogies?

Analogies

In the following passage Gribbin uses the words “analogies” and “model[s]” interchangeably. He writes:

“With [] great analogies to draw on — the nuclear model of the atom [] the QED theory of light [] the quark model of protons and neutrons and the QCD theory of the strong interaction [].”

As already stated, the above is more or less a standard take on models in physics: it’s what Gribbin argues next which is more radical:

“‘Analogy was not one option amongst many,’ says [Andrew] Pickering [the constructivist mentioned earlier]; ‘it was the basis of all that transpired. Without analogy, there would have been no new physics.’
“The same is true of quantum mechanics itself. Indeed, it is hard to see quantum physics as anything but analogy [].”

And, as with the question about models earlier, some readers may now ask the following question:

Analogies… of what?

In other words, don’t we have models and analogies of things which aren’t themselves models and analogies?

It may even seem that Gribbin is talking about analogies of analogies — full stop. After all, he does use the words “anything but analogy”. But if analogies (as well as models) are literally all we have, then how can they be analogies at all? That said, it may only be through analogies — or models — that we can arrive at things which aren’t themselves analogies (or models). And this is certainly what Hawking believed (as shown earlier) about scientific models.

All Interpretations are Equal?

When it comes to the interpretations of quantum mechanics, John Gribbin suggests that one helpful possibility (or suggestion) is to “buy the lot”. He suggests this because

“each of the interpretations is a viable model, and each of them provides us with useful insights into the way the world works”.

Gribbin seems to have been influenced by the American physicist Heinz Pagels (1939–1988) when it comes to buying this bulk-buy pluralism. Gribbin refers to Pagels’ own position, in which Pagels argued that

“we should learn a little about the quantum world from each of the interpretations, considering all of them together in a kind of superposition of possibilities”.

And then (referring to a situation mentioned earlier) Gribbin continues:

“Few of the experts, however, are broadminded enough to take this view. Instead, you tend to find that individual physicists (those who bother to think about these things at all, that is) cling stubbornly to the notion that their own favoured interpretation is correct, and that all of the other interpretations are ‘obviously’ wrong.”

There may well be an argument that all interpretations are superfluous when it comes to predictions, (quantum-based) technology, etc. However, that certainly doesn’t mean that all interpretations are “equally good”. They may be equally good in the sense that they don’t make the slightest bit of difference when it comes to the mathematical theory, predictions and technology. However, are they all equally good in literally every respect?

Of course being a pluralist doesn’t mean one needs take all the interpretations to be equal. More strongly, it doesn’t mean that they actually are equal. So one must assume that an outrightly silly interpretation would be rejected by Gribbin.

Another way of putting this is to argue that even if we accept the essential limitations of all the interpretations (and that no single one gives us a complete picture), then that doesn’t also mean that all interpretations must be treated equally.

In detail. What if Interpretation A (or its “useful insights”) outrightly contradicts Interpretation B? That said, it can be supposed that if one chooses A on one (as Gribbin puts it) “day of the week”, and B on another day of the week, then any contradictions between them simply may not matter. Alternatively, A and B may be being bought for different reasons, rather than on different days.

More mundanely, take a murder that hasn’t be solved and which has engendered numerous interpretations (or, at least, explanations). Does that mean that all these explanations/interpretations of the murder should be treated equally?

All the above seems to lead to this question:

So how truly pluralist is John Gribbin’s pluralism?

Gribbin’s Faves: The Many-Worlds and Transactional Interpretations

At some points in his books Gribbin seems to argue that all interpretations of quantum mechanics are equal. At other points… he doesn’t. One can therefore conclude by saying that Gribbin believes that some interpretations are more equal than others. (Actually, he believes that about two interpretations — the many-worlds interpretation and the transactional interpretation.)

Gribbin admits this when he states that “[t]he time has come for me to nail my colors the mast”. He also writes:

[The many-worlds interpretation] is still my favourite among the traditional interpretations, and if I were forced to offer a ‘best buy’ from all the ideas outlined so far this would be it.”

Moreover, Gribbin’s pluralism seems to be contradicted by his strong criticisms of the Copenhagen interpretation (which he’s expressed many times in many books) —and that’s alongside his strong commitment to the many-worlds interpretation and the transactional interpretation.

For example, Gribbin is partly factual and partly judgmental when he tells us that it is

“an historical accident is that [the Copenhagen interpretation] was the first interpretation that could be made to work, in the sense of providing recipes that quantum cooks who did not want to bother with the deeper mysteries and the philosophy could use to bake quantum cakes”.

He then says that the Copenhagen interpretation doesn’t care “[h]ow you choose to interpret [because] what is going on is largely up to you”. Indeed Gribbin continues by stating that “[t]here is no official ‘interpretation’ at this level”. All we have is (in basic terms) loads of experiments and probabilities.

As already stated, Gribbin favors John G. Cramer ’s transactional interpretation.

Cramer’s Transactional Interpretation

Interestingly enough, it turns out that Cramer is somewhat of a pluralist himself.

According to Gribbin, Cramer believes that his own interpretation is (simply)

“a tool which is likely to be particularly useful in teaching, and which has considerable value in developing intuitions and insights into otherwise mysterious quantum phenomena”.

And then Gribbin tells us exactly why he favours Cramer’s interpretation. He writes:

“The only valid criterion for choosing one interpretation rather than another is how effective it is as an aid to our way of thinking about these mysteries — and on that score Cramer’s interpretation wins hands down.”

Technically, in the transactional interpretation

[t]here is no need to assign a special status to the observer (intelligent or otherwise), or to the measuring apparatus”.

Moreover, because the transactional interpretations is

“going beyond the debate about the role of the observer [it] really does resolve those classic quantum mysteries”.

Yet even after these eulogies to Cramer’s interpretation, Gribbin can still be seen to be deflating it when he states the following:

“There is no problem at all with the mathematics of Cramer’s interpretation of quantum mechanics, because the mathematics, right down to Schrodinger’s equation, is exactly the same as in the standard Copenhagen Interpretation."

And finally:

“The difference is, literally, only in the interpretation.”

So even though many people may know that all interpretations (including Cramer’s) basically use the same maths and makes the same predictions, I personally — at least at first — still strongly suspected (or simply assumed) that the different interpretations did offer at least some additions (or slight tweaks) when it comes to the maths, predictions, etc. Yet this simply isn’t so — at least (according to Gribbin) when it comes to Cramer’s own interpretation of quantum mechanics.