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.

Old-Style Rationalism and Laurence BonJour’s New Rationalism

According to the philosopher Galen Strawson, if you’re a rationalist, then “you can see that something is true just by lying on your couch”. Indeed “you don’t have to do any science” or even “go outside and examine the way things are”.

This is an essay on old-style (usually called “early modern”) rationalism. However, it will still — at least to a small degree — apply to various contemporary rationalists and their positions…

Contemporary rationalists… really?

Wikipedia names the following philosophers as “rationalists”: David Chalmers, Noam Chomsky, Alvin Plantinga, Ernest Sosa, Ayn Rand, etc. I personally believe that not one of the philosophers named by Wikipedia is actually a rationalist — at least not a rationalist in the old style. The same is (more or less) true of the philosophers named as “rationalists” in other places: George Bealer, Henri Bergson, Robert Brandom, Thomas Nagel, etc. However, perhaps all this simply means that there were new 20th-century (in the plural) styles of rationalism. Alternatively, this may also show that it’s unwise to get too bogged down in isms.

In any case, one clear example of a genuine contemporary rationalist is Laurence BonJour (1943-), and he’ll be discussed at the end of this essay.

To get back to the ism under debate.

The adjective “old-style” is used in the title because there have been various (in the plural) rationalisms . For example, what may be called moderate rationalism only has it that (in Daniel Garber’s words) “reason has precedence over other ways of acquiring knowledge”. However, (as it were) immoderate rationalism has it that reason is “the unique path to knowledge”.

In terms of immoderate rationalism.

The English philosopher Galen Strawson summed it up by stating that if one is an immoderate rationalist (a term he doesn’t himself use), then this follows:

“[Y]ou can see that it is true just lying on your couch. You don’t have to get up off your couch and go outside and examine the way things are in the physical world. You don’t have to do any science.”

Moderate rationalism seems harmless enough and it may even be accepted by non-rationalists. That may be because, at least as it stands, Robert Audi’s earlier words (i.e., “reason has precedence over other ways of acquiring knowledge”) can be interpreted in all sorts of different ways. (It also depends on how the word “reason” is defined.) The second position of immoderate rationalism, however, certainly does seem extreme and, indeed, old-style.

Finally, it’s worth stating that the distinction between rationalism and empiricism came about only after the well-known rationalists (at least the ones featured in this essay) had done all their work. So such a distinction isn’t something that would have been recognised by the philosophers now classed under this ism.

Now let’s go into a small amount of detail on René Descartes (1596–1650).

René Descartes

Let A.L. Michael sum up Descartes’ rationalism in the following passage:

“Descartes thought that only knowledge of eternal truths — including the truths of mathematics, and the epistemological and metaphysical foundations of the sciences — could be attained by reason alone; other knowledge, the knowledge of physics, required experience of the world, aided by the scientific method []. Descartes developed a method to attain truths according to which nothing that cannot be recognised by the intellect (or reason) can be classified as knowledge. These truths are gained ‘without any sensory experience’, according to Descartes.”

The passage above shows readers how a rationalist like Descartes managed to create a strong distinction between physics and the philosophical disciplines known as epistemology and metaphysics. That’s distinction is worth highlighting because, at least at first, those people who’re new to Descartes’ life and work may wonder how he squared his rationalism with his physics.

In actual fact, it was Descartes’ epistemology which he hoped (or believed) would provide a strong foundation for the sciences of his day — specifically for physics (see here).

However, this neat division between epistemology and metaphysics (which don’t require sensory experiences) and physics (which does) is problematised by the positions of both Baruch Spinoza (1632–1677) and Gottfried Leibniz (1646–1716).

Spinoza and Leibniz believed that, at least in principle, literally all knowledge — and that included knowledge as it’s found in science (well, physics) — could be acquired through reason alone.

Technically, this strong science-philosophy (or at least mathematics-philosophy) link is demonstrated by the fact that Leibniz and Spinoza (especially Spinoza) at various points attempted to start with basic principles which worked like the axioms of geometry (see Spinoza’s Ethics here). And from these axioms, these philosophers believed that they could deductively derive the rest of all possible knowledge. (In terms of the history, these approaches largely occurred as both negative and positive responses to the work of Descartes — see here.)

All that said, both Spinoza and Leibniz sometimes acknowledged (in their various ways) that such (as it were) rational universalism isn’t easy — or even possible - in practice.

Pure Thought?

One may wonder why these 17th-century Rationalists believed all this stuff about “the power of Reason” and the irrelevance of sensory experience. (This was even truer, in many ways, of Plato.)

One way of capturing rationalists’ position on reality is to say that they believed that reality has a logical structure. (Not many rationalists, however, actually used the words “logical structure”.) This essentially means that not only is logic … well, logical: so too is the world or reality! And precisely because the world/reality is deemed to be logical, then that meant that rationalists — and perhaps others too— believed that they could directly grasp the world’s “certain truths” (or “principles”) through — or via — the use of reason. (As we’ll see later, this position squares with Laurence BonJour’s own.)

As a consequence of the above, if the world/reality itself was deemed to be logical by Rationalists, then it won’t be a surprise to find out that many of them also believed that morality, religion, and even politics and history have a logical structure.

Yet the very idea of “reason” or “thought” existing independently of all experience seems odd — at least outside the context of 17th-century rationalist philosophy. It simply doesn’t sound feasible at an intuitive level.

For a start, the words used by any rationalist will have been learned from experience. Indeed that’s the case even when it came to the logical rules and inferences the rationalists will have used. So even if what the logical rules and words express (i.e., their abstract content) it not itself part of experience, then that still doesn’t stop it from being the case that the words for these concepts, propositions and rules were learnt from experience.

So one could metaphorically argue that these Rationalists can no longer preach from the top of their rationalist tower if empirical and experiential means helped them get to the top of that tower in the first place.

Of course not all rationalists have denied these pollutions of their pure rationalism (i.e., as discussed in the introduction).

So what, exactly, did the pure rationalists think about?

Did they always think about some Platonic realm of abstract objects?

Does they only think about propositions, logical laws and “eternal principles”?

When a rationalist thought about reality (or even morality), did he think of such a thing exclusively in (to quote Kant) “the light of pure reason”? (A light that’s untouched by empirical vicissitudes and contingencies.)

Of course thought is more than experience.

Experience is experience and thought is thought.

However, thought relies on experience. Or, in Kant’s philosophy, thought relies on “sensory impressions” (or “phenomena”) in order to (as it were) get going. Yet of course the actual processes which the mind carries out in response to experiences aren’t themselves experiences. A logical inference, for example, isn’t an experience or an observation. (Even this claim depends on definitions.)

In addition, making a generalisation about one’s experiences or observations depends on those experiences or observations. However, the generalisation itself isn’t an experience or an observation. Indeed mental images or other acts of the imagination aren’t themselves experiences either. Nonetheless, they too may (or do) depend on experiences.

Not many (or indeed any) historical empiricists claimed that thought and experience are literally identical. Such empiricists didn’t — and couldn’t possibly — dispense with thought. That is obvious. The empiricist position requires thought that’s not entirely dependent on experience. Indeed the very articulation of an empiricist position requires non-empirical thought.

Yet, on the other hand, the immoderate rationalist claimed that he’d dispensed entirely with experience— even if only philosophically.

Immoderate rationalists have argued that “thought is the only source of knowledge”. Admittedly, some traditional empiricists did argue that experiences (or sense impressions) alone account for all knowledge. That said, other empiricists have argued that all knowledge is only “dependent” on experiences or sense impressions.

So what has given rationalists so much confidence in their rationalism?

Necessary Truths?

Traditionally, it was the status and existence of necessary truths that were vital to rationalism.

Rationalists have argued that empiricists can’t give us — or explain — necessary truths. In fact empiricists have happily admitted that they can’t give us necessary truths because they don’t even accept that such things exist in the first place (at least not outside mathematics and what are now called tautologies).

So why have these necessary truths been so special to rationalists?

They were special because they could be known to be both necessary and true with certainty and without recourse to experience or observations. And that’s precisely what most rationalists have demanded: certainty, truth and necessity. However, even though these necessary truths aren’t reliant on experience, at least some of them are still deemed to be about the world/reality. (See Bonjour later.) That is, they’re things that must be true about the world/reality. Indeed the world/reality can’t be any other way than that which is expressed by the relevant necessary truths (i.e., as they’re expressed in a natural language in the form of statements).

Still, according to the rationalist, when we observe the world/reality, we don’t discover these necessary truths simply by doing so. That is, necessary truths don’t come from the observations alone.

In certain cases (e.g., Kant’s), necessary truths are a “necessary condition” for observing or experiencing the world in the first place (see here). So these necessary truths are applicable to the nature of the world/reality. However, they aren’t entirely derivable from the world/reality. In that sense, then, necessary truths must transcend the world/reality. They transcend the world/reality as it’s observed or experienced.

More clearly and in the rationalist picture, certainties and necessities are never experienced at all.

They’re known exclusively through (or via) thought.

(To requote Strawson: “You can see that it is true just lying on your couch. You don’t have to get up off your couch and go outside and examine the way things are in the physical world.”)

Experience can’t tell us (or help us) when it comes to discovering (if discovering is an appropriate word here) these certainties and necessities.

And all the above is precisely why empiricists have rejected the very notions of necessity and certainty.

Both the rationalists and empiricists argued (in their various ways) that we don’t get sensory impressions from things, events, conditions, etc. that (as it it were) tell us that they’re necessary or certain. And that’s because necessity and certainty aren’t things to get experiences from — not even when they belong to things, events or conditions which are themselves empirical and which aren’t themselves necessary or certain.

Furthermore, some empiricists have argued (in their various ways) that a world which (as it were) contains necessities and certainties would be indistinguishable from a world which doesn’t do so. In other words, this is a (rationalists’) difference which doesn’t make a difference. And, because of that, such a (scare-quoted) “distinction” goes against one important aspect of empiricist philosophy.

Since (as it were) Rationalist Reality has just been discussed, let’s now bring this debate up to date.

Laurence BonJour’s New Rationalism

Take the case of Laurence BonJour (1943-).

BonJour belongs to a group of philosophers who’re re-evaluating rationalist philosophy.

Perhaps BonJour goes the furthest towards the kind of rationalism we would recognise from the rationalists of the late 17th and early 18th centuries. Nonetheless, there are still obvious differences between BonJour’s work and the Old-Style Rationalists.

As it is, BonJour describes himself as a “rationalist”. And, clearly, he’s also well aware of the criticisms of rationalism.

For example, in reply to the Australian philosopher Michael Devitt, Bonjour talks of Devitt’s

“allegations that rationalism is ‘objectionably mysterious, perhaps even somehow occult’ []”.

BonJour concludes by saying that he find these allegations “very hard to take seriously”.

Rationalist Truths About the World

BonJour believes that we can gain access to the necessary truths of the world via what he calls “rational insight”. He argues that rational insight

“occurs when the mind directly or intuitively sees or grasps or apprehends [] a necessary fact about the nature or structure of reality”.

BonJour also uses the words “necessary truth”. That is, BonJour ties necessity to truth. Again, in BonJour’s own words:

“[Michael] Devitt seems to me to be simply rejecting the idea that merely finding something to be intuitively necessary can ever constitute in itself a reason for thinking it is true [].”

Indeed BonJour goes further by stating the following:

“[A priori] insights at least purport to reveal not just that the claim is or must be true but also, at some level, why this is and indeed must be so. They are thus putative insights into the essential nature of things or situations of the relevant kind, into the way that reality in the respect in question must be.”

According to BonJour, then, necessary truths (or necessities themselves) aren’t a question of language, the synonymy of terms, the “structure of the mind” and all the rest: they’re about the nature (or structure) of the world/reality itself! (BonJour actually uses the words “properties of the world” when talking about such necessities.)

Thus we must immediately ask how the mind can grasp (by rational insight) anything about the world.

In addition to all the above, some contemporary rationalist philosophers are both reassessing the a priori as well as mounting a defence of it.

The A Priori

Commentators may say that it’s an exaggeration to claim that any contemporary philosophers are actually re-evaluating rationalism itself; rather than merely defending their more selective (epistemic) apriorism.

As for BonJour himself. The principle difference, to my mind, between BonJour’s rationalist philosophy and that of the Old-Style Rationalists is his acceptance of the possible experiential (or empirical) defeasibility of a priori claims, “reasons” or beliefs.

So BonJour’s own rationalism is actually encapsulated by his position on the a priori. The following is what he says on that subject:

“[I]f we never have a priori reasons for thinking that if one claim or set of claims is true, some further claim must be true as well, then there is simply nothing that genuinely cogent reasoning could consist in. In this was, I suggest, the rejection of a priori reasons is tantamount to intellectual suicide.”

But what does BonJour’s general rationalism amount to?

Take the following passage:

“[I]n the most basic cases such reasons result from direct or immediate insight into the truth, indeed the necessary truth, of the relevant claim.”

Now perhaps BonJour’s last claim takes us as far away from empiricism as we could possibly go.

Frank Jackson wrote: “Qualia are an excrescence.”

Frank Jackson also wrote that qualia “do nothing, they explain nothing, they serve merely to soothe the intuitions of dualists and it is left a total mystery how they fit into the world view of science”.

excrescence: noun (1) an abnormal outgrowth, usually harmless, on an animal or vegetable body. (2) a normal outgrowth, as hair or horns. (3) any disfiguring addition. (4) abnormal growth or increase.

[Mary and the knowledge argument won’t be considered in this essay.]

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The following passage (from the paper ‘Epiphenomenal Qualia’) is American philosopher Frank Jackson’s very-strong position against qualia:

“All right, there is no knockdown refutation of the existence of epiphenomenal qualia. But the fact remains that they are an excrescence. They do nothing, they explain nothing, they serve merely to soothe the intuitions of dualists, and it is left a total mystery how they fit into the world view of science. In short we do not and cannot understand the how and why of them.’”

… But hang on a minute!

The passage above is actually Frank Jackson expressing what he believed a “qualia sceptic” would say. (The passage above begins with these words: “There is a very understandable response to the three replies I have just made.”)

So some readers may see it as a bad idea to quote a defender of qualia putting the case against qualia.

The words “defender of qualia” have just been used even though Jackson later came to reject his (former) case against physicalism. The following passage shows us why Jackson changed his position on physicalism (if not, strictly speaking, specifically on qualia):

“Most contemporary philosophers given a choice between going with science and going with intuitions, go with science. Although I once dissented from the majority, I have capitulated and now see the interesting issue as being where the arguments from the intuitions against physicalism — the arguments that seem so compelling — go wrong.”

So it’s now worth asking if, after his about-turn, Jackson would have put his new position against qualia in the same — or in a similar — way to the way he expressed it when he put it in the mouth of a fictional qualia sceptic.

In any case, Jackson’s words are suspect in a number of ways. That said, perhaps they are so primarily (or simply) because they’re meant to be purely rhetorical in nature. After all, Jackson was putting his (at the time) opponent’s position in (presumably) as strong terms as possible.

To sum up five (among others) problems with the words of Jackson’s fictional qualia sceptic:

(1) Even if qualia are an “excrescence”, that doesn’t automatically mean that they don’t exist. 
(2) Some philosophers argue that qualia do some things. 
(3) Some philosophers argue that qualia explain some things. 
(4) Not all the people who accept the existence (or reality) of qualia are what Jackson called “dualists”. 
(5) Not “fitting into the world view of science” isn’t the same as clashing with — or contradicting — science.

(1) Do Qualia Exist?

“All right, there is no knockdown refutation of the existence of epiphenomenal qualia. But the fact remains that they are an excrescence.”

The first thing which needs to be said is that even if qualia are an “excrescence”, then that doesn’t automatically mean that they don’t exist (or have any reality). Moreover, even if qualia “do nothing” and “explain nothing”, then they may still exist (or have some kind of reality).

The English philosopher Roger Scruton (1944–2020) hinted at all this in his book On Human Nature (2017). Scruton claimed that the critical philosophical accounts of qualia didn’t actually disprove the existence of qualia altogether — even though he did find qualia problematic.

Yet surely all this hinges on which definitions — or features — of qualia are actually being offered or tackled. That said, Scruton still summed up his own problem by quoting a well-known passage from Wittgenstein:

“Whereof one cannot speak, thereof one must be silent.”

Indeed Wittgenstein’s words above perfectly express Daniel Dennett’s position, which we’ll come to in a moment.

Of course, if qualia fail in all the respects mentioned by Jackson’s qualia sceptic above (for now, let’s say that they do), then one can immediately ask how it is that they actually exist at all. More strongly, how can qualia be known to exist if they fail in all those respects?…

But, again, it depends on which account of qualia we have in mind.

Take the American philosopher Daniel Dennett.

Dennett does indeed deny the existence of qualia.

So when Dennett states that “qualia do not exist and are incompatible with neuroscience and naturalism”, we must find out what he takes qualia to be. And then it will soon be discovered that he’s actually against a very particular philosophical account of qualia. (All accounts of qualia are — to varying degrees — philosophical. )

The following is a list of the qualities and features which Dennett (questionably) claims qualiaphiles take to be definitive of qualia:

(1) qualia are ineffable
(2) qualia are intrinsic
(3) qualia are private
(4) qualia are directly or immediately apprehensible in consciousness.

And it’s precisely because Dennett is against a particular account of qualia, that even his own position — believe it or not (i.e., as a well-known qualia sceptic) — isn’t entirely clear.

For example, American philosopher Owen Flanagan wrote the following:

“Qualia are for real. Dennett himself says what they are before he starts quining. Sanely, he writes, “‘Qualia’ is an unfamiliar terms for something that could not be more familiar to each of us: the ways thing seem to us.’ [].”

That passage again simply raises the question: What does Dennett take qualia to be? Sure, we know what Dennett doesn’t take qualia to be, but what does he take them to be?

This may be the (or an) answer.

In ‘Are we explaining consciousness yet?’ (2001), Dennett argues that qualia are neural responses which are too fine-grained to be captured in any given natural language.

More broadly, then, it’s now widely accepted (at least among philosophers who’re interested in this issue) that the debate about qualia often hinges on the definition of the term “qualia”. More accurately, it strongly depends on what the various qualities and features of qualia are taken to be (e.g., as with Dennett’s own 4-point list).

In any case, most qualiaphiles (probably all) believe that there can never be a (to use Jackson’s words again) “knockdown refutation of the existence of epiphenomenal qualia”. And that’s simply because qualiaphiles (as it were) have (or claim to have) qualia. More accurately, most (or all) qualiaphiles believe that they have immediate and direct access to their own qualia (as in Dennett’s point 4). Indeed Jackson himself put this view in the following:

“As I say in the beginning of ‘Epiphenomenal Qualia’, we dualists don’t really need an argument to say that consciousness doesn’t fit into the physicalist world view. It’s just intuitively obvious.”

(This is similar to the argument which the English philosopher Philip Goff — along with David Chalmers before him — uses about consciousness generally; which, according to him, is a “datum in its own right”.)

Yet whatever it is qualiaphiles have access to, that doesn’t mean that what they have access to are qualia as they describe them. And neither does it mean that they can’t misdescribe qualia or believe that they have features or qualities which they don’t actually have.

In more abstract terms, even if our cognitive access to any given x is indeed immediate and direct (however we take those terms), the words and concepts we use about that x (alongside the statements we make about it) aren’t themselves immediate and direct. That is, all our words, concepts and even ways of description of x will be contingent and have social and psychological histories and aetiologies.

All that said, surely qualiaphiles — and all of us — do have direct and immediate access to some things they deem to be qualia. In other words, whatever we say about qualia (or however we describe them), then qualia may still be accessed immediately and directly… or will they?

(2) Do Qualia Do Things?

“They do nothing…”

When Frank Jackson claimed that qualia “do nothing”, he was expressing an epiphenomenalist position. But need one take such a position on qualia?

So, firstly, let’s run through four basic positions:

(1) If qualia are physical, then of course they can do things. 
(2) Even if qualia aren’t physical, then they can still do things. 
(3) If qualia don’t exist, then that which doesn’t exist can’t do anything. 
(4) Qualia exist, aren’t physical and they don’t do anything (i.e., the epiphenomenalist position).

Jackson now believes that, say, the experience of blue is entirely instantiated in the brain. (The notion of an experience is surely wider than that of a single quale, such as one of the colour blue — if there even is such a thing.) This also means that such an experience will immediately cause other changes in the brain.

Paul Churchland also provides a physical and neuroscientific account of qualia. So he isn’t actually a qualia sceptic at all (see his ‘Knowing Qualia’). Yet Churchland’s account of qualia is one that most (perhaps all) qualiaphiles will be very unhappy with. So, here again, what Churchland takes qualia to be clashes violently with what qualiaphiles — and perhaps most people — take qualia to be.

(3) Do Qualia Explain Things?

“[T]hey explain nothing…”

Frank Jackson’s statement above depends on what, exactly, needs to be explained. It also depends on the strength (or lack thereof) of the explanations in which qualia feature. Conversely, it depends on why qualia sceptics believe that such explanations (or at least most of them) are effectively non-explanations.

Qualiaphiles argue that their having of qualia explains all sorts of things.

Pain is an obvious example. The having of a toothache will (if loosely) explain that a tooth is rooting away. Hearing the sound of a trumpet is a good explanation as to which instrument my neighbour has now taken up…

But are these really examples of qualia?

Basically these and other examples won’t work as explanations unless the qualiaphile tells us exactly what he takes qualia to be. And qualia sceptics don’t accept what qualia are taken to be. That is, they don’t deny the having of pains or the hearings of musical instruments. What they do deny is that these things are explained by philosophical qualia.

(4) Must All Those Who Accept Qualia Be Dualists?

“[T]hey serve merely to soothe the intuitions of dualists…”

This statement is an obvious ad hominen. Yet, of course, it’s Frank Jackson’s fictional physicalist (or qualia sceptic) who’s talking. That said, Daniel Dennett (again) said more or less the same thing (if about consciousness, not, strictly speaking, about qualia) when he wrote the following:

“To many people consciousness is ‘real magic’. If you’re not talking about something that is supercalifragilisticexpialidocious, then you’re not talking about consciousness, the Mystery Beyond All Understanding.”

As it is, there’s no strong reason to be against ad hominins when they’re placed (as the cliche has it) within context. That is, if an article, paper or even a single paragraph were made up entirely of ad homs, then that wouldn’t be worth reading — at least not from a philosophical point of view. Yet there’s no reason why every single sentence in a philosophical paper or essay need be an argument or even be particularly philosophical. What’s more, one can sometimes — and in some ways — get a grip of arguments and philosophical positions with the help of ad homs and psychologisations — as historians, biographers, novelists, dramatists, etc. are well aware.

But what of the “intuitions of dualists”?

Even if qualiaphiles’ intuitions are being “soothed” by qualia, then they may still offer good arguments to back up their qualiaphilia. Indeed who’s to say that all qualiaphiles are (psychologically) soothed by qualia in the first place? Perhaps they simply believe that they exist - full stop.

Philosophically, however, Jackson’s (as it were) accusation of dualism is surely correct. That is, if a qualiaphile takes qualia to be non-physical, then he must be a dualist. More accurately, if a qualiaphile believes that qualia do things at the very same time as their being non-physical, then he must be a dualist.

Qualia and Science

“[I]t is left a total mystery how they fit into the world view of science.”

Qualiaphiles — and others! — may ask if science has a single “world view”.

More relevantly, they may ask if science has a single — or indeed any — world view on the subject of qualia at all.

That said, Frank Jackson’s qualia sceptic might have meant that it’s the world view of science-as-a-whole that qualiaphiles need to (as it were) accommodate — i.e., regardless of whether or not Science-with-a-capital-‘S’ has (or doesn’t have) a position on qualia.

Moreover, even if science does have a world view, then that world view may change. Indeed it must have already changed through the centuries. In other words, surely the world view of science (if it exists at all) can’t be determinate and fixed. More relevantly, that world view may come to accept qualia. Alternatively, it may come to completely reject qualia. (Of course this last possibility jars with the earlier question about science having a single world view.)

In any case, all this is complicated by fact that the scientists who do concern themselves with qualia have three (main) mutually-contradictory positions on them:

(1) Qualia exist and can be given a scientific description. 
(2) Qualia exist but can’t be given a scientific description. 
(3) Qualia don’t exist in the first place.