Do People Really Write (or Read) and Listen to Music at the Same Time?

 

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“Another benefit of listening to music while reading is that music can help you retain information. This is because listening to music can activate the left part of your brain and the right part of your brain simultaneously. This allows for increased levels of retention and understanding, which can help you read.”

— See source here.

“Yes! I can’t read without music! Honestly, I can’t do anything without music.”

— See source here.

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Some readers may wonder how reading (or writing) and simultaneously listening to music fits into Bernard J Baars’s* post above.

Sure, you can’t concentrate as much on the music as you could do if you listened to it exclusively. However, surely these two things do occur together. Indeed, listening to music and reading (or writing) at the same time is a common phenomenon.

Of course, it may be the case that we switch from one to the other. (Baars talks in terms of “once flow of information will always interrupt another”.)

So readers should try a phenomenological experiment here.

Personally, it’s hard to tell if switching is actually going on.

For example, while writing these very words, I’m aware of the music in the background. I must be! I can note the tunes, the harmonies, and even the moods and emotions the music brings about. What’s more, if something very surprising occurred in the music (or a particularly “catchy” bit came up), then I’d immediately notice that. This strongly suggests that I’m (nearly?) always aware of the music while writing…

Actually, surely I am listening to the music while writing!

So, on the surface at least, there’s no total (or complete) switching between writing and listening to the music. (Again, Baars writes: “Conscious involvement with one flow of information will always interrupt another.”) However, there may well be a lesser degree of switching occurring. In other words, the music is less focussed upon than it would be if I were not writing. However, and as already stated, the music is still being listened to.

Ned Block on Phenomenal Consciousness and Access Consciousness

All this reminds me of an example from the American philosopher Ned Block. This is of someone writing (or reading), and all along there’s the sound of church bells coming from outside his home. The reader (or writer) hears the church bells at all times. However, only at a certain time does he actually note (a loose word, admittedly) that it’s church bells that he can hear.

As Block puts it: this person is phenomenally conscious of the church bells all along. However, he becomes access conscious of the bells only at a certain point.

The terms of the trade have it that the hearing of the church bells (though not as church bells) is an example of (according to Block again) “phenomenal consciousness without access-consciousness”. (“Access-consciousness” includes the application of concepts — among other things - to “phenomenal consciousness”.)

To clarify. A person can hear church bells, and not hear them as church bells. In other words, concepts may not be applied to all the sounds a person hears. (This way of putting it doesn’t seem to be as easily applicable to my own writing-while-listening-to-music example.)

Are these examples of experiences in the strict sense?

It could be the case that while these sounds are entering consciousness, the mind is applying concepts to other things instead. So the sensory input from the the church bells (or from the “background music”) are in (as it were) outer consciousness. The sounds aren’t experiences in that the mind doesn’t infer anything from them. They’re not, as Block himself puts it, “poised for reasoning”. And they’re certainly not an epistemological “given” because there’s no cognitive awareness of — or relation to — the sounds.

Thus, these sounds can’t be the ground for inferences, knowledge or anything else.

To sum up. Nothing is derived from the sound of the church bells when they’re not heard as church bells.

The philosopher John Searle clarified things a little here.

Searle argued that we can call the sound of church bells (or the music listened to while writing) an example of what happens in “peripheral consciousness”.

The American philosopher Jennifer Church also cited an example of supposed phenomenal consciousness when she wrote the following words:

“Consider the example of a noise that I suddenly realise I have been hearing for the last hour. [Ned] Block uses it to show that, prior to my realization, there is phenomenal-consciousness without access-consciousness.”

This would be an example of Searle’s peripheral consciousness. However, Jennifer Church even denied (or doubted) the possibility of true phenomenal consciousness without access consciousness. She continued:

“[I]t seems that I would have accessed it [the noise] sooner had it been a matter of greater importance — and thus it was accessible all along. Finally, it is not even clear that it was not actually accessed all along insofar as it rationally guided my behaviour in causing me to speak louder.”

This is roughly equivalent to my own example of suddenly paying more attention to the music when, say, some catchy tune pops up. (Or perhaps when the internet connection cuts off the music entirely.)

Ned Block himself comes up with an alternative way of describing this putative before-noon pure example of phenomenal consciousness: “P-consciousness without attention.” I would say, perhaps only as a paraphrase, PC with inattentive AC (access consciousness). To use John Searle’s term again, the noise of church bells before noon (or the music in the background) was mainly peripherally conscious, although never an example of pure phenomenal consciousness.

Strangely enough, while writing some of the words above there was a noise outside my own flat. I didn’t pay attention to it. I was inattentive. (The noise was in peripheral consciousness.) However, I knew all along that it was at least a noise. Indeed, perhaps all along I knew that it was a car alarm. After all, if the car alarm had seamlessly turned into a scream (if you can imagine such a thing), then I would have become more attentive to the noise.

Concluding Note: What About the Brain?

Some readers may wonder how the (as it were) facts of the matter would be established in the cases discussed above. After all, the whole thing is dependent upon my own “verbal reports” (or subjective reports) on what’s going on inside my head. My own personal reports could, of course, be correlated with other people’s verbal and subjective reports on the same issue. And much could be concluded from that. However, we’d still only have various verbal reports about subjective experiences.

So some readers may also wonder (i.e., as non-specialists) what’s going on in the brain to make all this possible. Perhaps neuroscience could provide an answer to the limited scope of all the verbal reports about what subjectively occurs when reading (or writing) and listening to music at the same time.

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(*) Bernard J. Baars (born 1946) is a neuroscientist who’s best known as the originator of the global workspace theory. He has worked as a professor of psychology at the State University of New York, Stony Brook.

When It Comes to Science, Non-Scientists Rely on Testimony

 

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(i) Introduction

(ii) Scientific Testimony

(iii) Wikipedia on the Philosophy of Testimony

(iv) Wittgenstein on Doubting All Testimony

(v) David Lewis on What We Can Properly Ignore

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First things first. Readers should note that the argument being advanced in the following essay isn’t that all scientists utter the absolute truth every time they open their mouths. (Thus, that we should believe literally everything scientists say.) And neither is it being put forward that all non-scientists know nothing much about any scientific subject. (In certain cases, non-scientists may actually know more than professional scientists when it comes to specific issues or subjects.)

Still, scientific testimony is a real thing.

And this is certainly more the case when it comes to some scientific subjects (such as mathematical physics generally, or string theory particularly), than when it comes to other scientific subjects.

What’s more, scientists themselves often rely on testimony. Indeed, that’s even the case when it comes to their very own specialisms!

Introduction

In my essay ‘Physicist Peter Woit on the Sociology of String Theory’ I said that, to a non-physicist such as myself, Peter Woit’s criticisms of string theory certainly seem convincing. And then, after quoting Woit’s technical take on this issue, I continued with the following passage:

“I used the words ‘to a non-physicist’ just before I quoted the long passages above. I’m not saying that all readers need to be professional physicists in order to make sense of the scientific parts. However, I certainly don’t feel qualified enough to come down either way on many of Peter Woit’s scientific pronouncements.”

I then promised to go into detail on this.

Scientific Testimony

Now take a look at this meme:

There’s an element of truth in the meme above. Personally, I feel like I’m encroaching on sacred territory whenever I comment on physics — especially on string theory. Put simply, I don’t know the maths. Thus, to varying degrees, I must rely on what philosophers call testimony…

Not that any single testimony — even a large scale set — could ever be decisive when its comes to a non-scientist (or a layperson) accepting a scientific idea or theory. After all, the community of physicists itself contains members who often (sometimes strongly) disagree with each other.

And it can’t all be about body counts (i.e., or the “scientific consensus”) either.

The other thing about the meme above is that particle physicists themselves say that other “particle physicists are wrong”. Some physicists say that string theorists are wrong. Indeed, some string theorists say that other string theorists are wrong — at least on details.

So how does a layperson deal with the claims of scientists?

More specifically, how does a layperson deal with statements about string theory, M-theory, the multiverse, the Big Bang, cosmic inflation, dark matter, black holes, etc?

I’ll come clean here…

Again, when it comes comes to mathematical physics generally, I mainly rely on testimony.

Indeed, when it comes to string theory specifically, what else can I rely on other than testimony?…

I’m not a physicist.

I’m not very good at maths.

Sure, I know a bit about physics, and some basic maths. I also know (or I may know) the non-mathematical parts of the physics I comment upon.

But is all that enough?…

Enough for what?

Well, it depends.

So if we take Peter Woit’s own words on string theory again, then I certainly don’t know all the maths or physics. I probably don’t even know 1% of the maths. (This is, of course, an entirely arbitrary percentage.)

So where does that leave me?

Indeed, where does it leave other non-scientists (or laypersons)?

It leaves me (if not all other laypersons) with philosophy of science books and papers, as well as popular-science books and articles.

Again, is that enough?…

All that said, many non-physicists certainly do believe that they have enough knowledge and wisdom to come down strongly in favour (or against) string theory, M-theory, the multiverse, the Big Bang, cosmic inflation, dark matter, black holes, the standard model, etc. (Many non-scientists also have an aesthetic taste for particular interpretations of quantum mechanics.)

Yet surely science mustn’t be the sole preserve of professional scientists.

That said, even after reading many introductions to scientific issues, it’s still very difficult for a non-scientist to come down on any side. Or, rather, it isn’t difficult for some laypersons, but it is for others.

In terms of string theory again.

I personally don’t have a firm scientific position on string theory. I certainly don’t adopt any strict scientific position on it. That’s primarily because any position (at least of a scientific nature) on string theory must — almost of necessity — involve complex mathematics, as well as a deep knowledge of mathematical physics generally…

Yet (as already stated) I’m neither a mathematician nor a physicist.

So where does that leave me?

Where does that leave all non-scientists (or laypersons)?

All that said, it’s also the case that nothing advanced in this essay depends on my knowing the complex mathematics required for any scientific theory. Indeed, everything said should stand (or fall!) without such detailed technical knowledge…

But what, exactly, is testimony?

Wikipedia on the Philosophy of Testimony

Take these introductory remarks on testimony:

“[I]t seems that many of the beliefs that we hold have been gained through accepting testimony. For example, one may only know that Kent is a county of England or that David Beckham earns $30 million per year because one has learned these things from other people.”

Couldn’t it be argued that most (i.e., not many) “of the beliefs that we hold have been gained through accepting testimony”? That said, individuals hold so many beliefs that it would be almost impossible to quantify, and then answer, this question. In any case, the two examples given in the passage above could be added to indefinitely when it comes to the set of beliefs the average person holds.

When it comes to string theory (or any other complex theory from physics), then isn’t (almost?) everything the layperson holds based on testimony?

The quoted passage above continues in the following manner:

“One of the problems with acquiring knowledge through testimony is that it does not seem to live up to the standards of knowledge. As Owens notes, it does not seem to live up to the Enlightenment ideal of rationality captured in the motto of the Royal Society — ‘Nullius in verba (Into the word of no one)’. The Royal Society interprets this as ‘take nobody’s word for it.’"

All this depends on which “standards of knowledge” we have in mind. Perhaps there is no definite article when it comes to the “standards of knowledge”. Or, rather, there may be, but only if we single out (as this writer has done) something like “the Enlightenment ideal of rationality”.

Indeed, we can even question this standard of knowledge (i.e., “take nobody’s word for it”) because it may be impossible to abide by. On a daily practical level, this would certainly be the case. However, even philosophically, it may be too much to ask.

What’s more, if this version of the Enlightenment ideal of rationality is truly an impossible ideal, then in what sense can we call it a definition of (or take on) rationality at all?

In addition and self-referentially speaking, don’t some of us take it on testimony that this Enlightenment ideal of rationality is itself, in fact, a true or worthy ideal? Moreover, is the aim of knowledge (or rationality) really to “take nobody’s word for”… anything? [This was Descartes’ starting point in his Cogito.]

Try it.

Try taking no one's word for anything.

Then see how things turn out.

Thus, this (as it were) radical Enlightenment stance on rationality (or knowledge) may itself need to be accepted on testimony — at least at first.

In any case, the quoted passage from Wikipedia ends with this final question:

“Crudely put, the question is: ‘How can testimony give us knowledge when we have no reasons of our own?’”

Is this correct?

We may have “reasons of our own” for accepting other people’s reasons of their own. After all, accepting only one’s own “word for it” could literally incapacitate us. Thus, knowledge-wise, we’d then possibly be in a worse position than the gullible person who accepts everything everybody says.

Now take Wittgenstein’s case against global scepticism (or against global doubt), and how it can be connected to taking any strong position on testimony.

Wittgenstein on Doubting All Testimony

This is how Ludwig Wittgenstein put matters in his posthumous book On Certainty:

“The questions that we raise and our doubts depend on the fact that some propositions are exempt from doubt, are as it were like hinges on which those [doubts] turn.

“That is to say, it belongs to the logic of our scientific investigations that certain things are in deed not doubted…

“My life consists in my being content to accept many things.”

We can’t doubt anything without exempting certain others things from doubt. Thus, the basic position here is that even philosophical doubt requires belief. In other words, in order to get the game of doubt under way, certain things must be placed beyond doubt.

In terms of testimony itself, that paragraph directly above can now be rewritten in this way:

We can reject (or doubt) a single case of testimony while also exempting many others cases of testimony from doubt.

The basic position here is that even philosophical doubt about certain cases of testimony requires belief about other cases. In other words, in order to get the game of rejecting (or doubting) testimony under way, certain other examples of testimony must be placed beyond doubt.

To give a mundane example.

Say that you’re doubting a friend’s testimony when it comes to (as it were) the facts of geography. You wouldn’t also thereby doubt the very meanings of your friend’s (non-technical) words.

That would be semantic doubt, not geographical doubt.

Similarly, you wouldn’t contemplate the possibility that your friend’s statements about geography are actually coming from a person, rather than from a robot or an evil demon. That would be a doubt about “other minds”, not a doubt about geographical statements.

So what’s at the heart of these “exemptions from doubt” is the “context” in which each case of testimony takes place. As Wittgenstein (again) put it:

“Without that context, the doubt itself makes no sense: The game of doubting itself presupposes certainty.”

“A doubt without an end is not even a doubt.”

If one rejects (or doubts) every case of testimony, then there’s no sense in rejecting (or doubting) any case of testimony. Thus, doubts about particular cases of testimony must occur within the context of belief.

So it’s worth bringing in the American philosopher David Lewis here.

David Lewis on What We Can Properly Ignore

At least within the limited (or strict) domain of epistemology, David Lewis (1941–2001) introduced the notion of what can be “properly ignored”. This is the idea that certain “sceptical possibilities” can be properly ignored if they’re deemed to be irrelevant.

Similarly, one needn’t be sceptical about (or one needn’t question) all cases of testimony.

Strictly speaking, Lewis’s account of the notion of properly ignoring (sceptical) possibilities applies (as with Wittgenstein) only to specific contexts. The following passage is Lewis himself on this matter:

“I may properly ignore some uneliminated possibilities; I may not properly ignore others. Our definition of knowledge requires a sotto voce proviso. S knows that P iff S’s evidence eliminates every possibility in which not-/’ — Psst! — except for those possibilities that we are properly ignoring.”

However, both Lewis himself and other philosophers broadened this notion out to include other cases.

Lewis himself specifically mentioned testimony. He asked his readers the following question:

“What (non-circular) argument supports our reliance on [] testimony?”

Lewis’s point was that Smith’s reliance on testimony (as well as on perception and memory) in the past is believed (by Smith himself) to justify his reliance on testimony in the present…

Yet surely this is a circular position.

In other words, Smith is using his prior reliance on testimony to justify his present reliance on testimony.

What’s more, what if Smith hadn’t even justified his prior reliance on testimony? Would this mean that his present reliance wouldn’t be justified either?

Of course, it might well have been the case that Smith’s prior reliance on testimony was indeed justified. However, do his previous justifications automatically mean that he doesn’t need to (re)justify his present reliance on testimony?…

Psst!

And this is where David Lewis argued that we know certain things even though “we don’t even know how we know”. Or, as Lewis also put it, “justification is not always necessary”.

Sexy Popular Science: The Multiverse, Many Worlds, and Quantum Stuff

 

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“Unsurprisingly, pop culture gets the multiverse wrong.”

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(i) Introduction

(ii) The Sexy Multiverse

(iii) Sexy and Weird Quantum Mechanics

(iv) Schrödinger’s Sexy Cat

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Pop culture often gets these things wrong partly — or even largely — because of what physicists themselves write and say. More accurately, it gets things wrong because of what physicists write in their “popular science” books.

So perhaps this is what Carlyn Zwarenstein means by “pop culture” — stuff that includes books and articles written by professional scientists. (She mentions the science writer and physics professor Paul Halpern later.)

In the case of the tweet above, why is there an assumption here that pop culture is getting things wrong when it comes to (what she calls) “multiverse theory”? After all, lots of theoretical physicists, physicists generally, philosophers, etc. have a serious problem with this theory too. They also disagree a lot on this subject.

The other thing about this tweet is that it also assumes that there’s a single pop-culture view of the multiverse.

So perhaps all this boils down to the vagueness (or inaccuracy) of that very term — “pop culture”.

All this has also got a lot to do with scientists (i.e., not pop culture!) attempting to make their scientific specialisms and interests sexy.

There are two main reasons why such scientists tart up (their?) science:

(1) In order to get more people interested in science.

(2) To help sell more of their own books.

Of course, there’s nothing wrong with simplifying science for a general audience. (I myself rely on such simplifications.) However, there is something wrong with attempting to make things sexier than they actually are. More importantly, there is a problem if the sexed-up science is actually misleading — or even downright false!

Take the case of the multiverse, as referred to in Carlyn Zwarenstein’s tweet.

The Sexy Multiverse

Firstly, I’m aware that many-worlds theory and ideas about a multiverse are very different. (There are even many different accounts of the multiverse, what it is, and how it came about. See note 1.) However, the existence of many worlds and the multiverse are both deemed to be equally sexy.

I’m also more than willing to accept that it’s possible that there are many worlds, or that there’s a multiverse. I’m even willing to accept that many worlds actually exist. However, I’m not willing to accept the titillating, sexy and self-obsessive crap that’s said about them by… scientists.

The science writer Philip Ball tells us why many people find many-worlds theory (or, more accurately, the many-worlds interpretation) appealing. He writes:

“Alternative realities hold an irresistible allure. Whether it’s Dickens’ A Christmas Carol, Frank Capra’s It’s a Wonderful Life, or the quantum-computed parallel universes of Alex Garland’s recent TV series Devs, the possible lives that we can imagine having led but did not lead offer a stage for acting out our fears and fantasies.”

Ball then ties all that to the science… or, more precisely, to the interpretations of the science. He continues:

“It is no surprise, then, that the Many Worlds interpretation (MWI) of quantum mechanics seems to hold such attraction. Even though most physicists dismiss or even deride it, it is often eagerly embraced by physics popularizers and their audiences. Yet it can be hard to figure out how seriously some of its advocates really take it. I believe some physicists genuinely see it as an elegant solution to deep conundrums of the notoriously mind-bending quantum theory, and I sympathize with some of their reasoning. But when they start talking about ‘quantum brothers’ (and presumably sisters, though Many Worlds has curiously few female advocates) [] I have to wonder whether, indifferent to the philosophical complications, they are just enjoying the fantasy.”

Note the words “[j]ust enjoying the fantasy”.

And what’s wrong with that?

Nothing... at least outside of any context.

As long as we all realise that’s precisely what it is: people just enjoying the fantasy.

What’s more, it’s not as if Philip Ball has just made all this stuff up either. For example, according to the science writer John Gribbin, “[t]here really is [] a Wuthering Heights world (but not a Harry Potter world)”.

Interestingly enough, Carlyn Zwarenstein (i.e., the author of the opening tweet above) also touches on this issue in the following passage:

“‘Forward time travel is possible if you can approach the speed of light,’ says Paul Halpern [], a physics professor and prolific science writer whose book about the concept of the multiverse, The Allure of the Multiverse: Extra Dimensions, Other Worlds, and Parallel Universes, was just published.

“Yesssss! That’s more like it.

“But as usual, science is out to burst this writer’s bubble. As it turns out, you can’t approach the speed of light. (Well, not with that attitude).”

Readers will have noted the words “The Allure of the Multiverse”!

If we return to Philip Ball. He’s not alone on this “postmodern science” bonanza. Take the following critical views of the multiverse theory… and string theory.

Firstly, here’s the science journalist John Horgan:

“[S]cience that is not experimentally testable or resolvable even in principle and therefore is not science in the strict sense at all. Its primary function is to keep us awestruck before the mystery of the cosmos.”

And now for Jim Holt:

“For the first time in its history, theory has caught up with experiment. In the absence of new data, physicists must steer by something other than hard empirical evidence in their quest for a final theory.”

Perhaps Horgan and Holt are themselves part of the “pop culture” referred to in the opening tweet. That said, I’ve already made the point that there are plenty of professional physicists who’re critical of the multiverse, many worlds, etc.

Now Take the word “weird”, which is relentlessly used when it comes to quantum mechanics.

Sexy and Weird Quantum Mechanics

As a starter, click the words “Quantum mechanics is weird” as they’re fed into Google search. You’ll get hundreds — possibly thousands — of entries and links which take you to films, books, articles, papers and documentaries.

Here again, it’s often physicists themselves who stress the “weirdness” of quantum mechanics, not pop culture. And I suspect that many physicists do so in order to entice laypersons into (their?) physics.

In any case, I have backup here.

In 2018, the science writer Philip Ball had a book published called Beyond Weird: Why Everything You Thought You Knew About Quantum Mechanics is Different. In that book he downplays the “weirdness” of quantum mechanics, at the same time as he stresses new approaches to its interpretation.

The physicist Christopher Fuchs (as quoted by Ball) also expresses the problem with quantum mechanics in terms of “all the posturing and grimacing over [its] paradoxes and mysteries”. In other words, for many laypersons and popular-science writers especially, that posturing and grimacing seems to have become the very essence of quantum mechanics.

Philip Ball also cites Richard Feynman’s often-quoted words:

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

Thus, from the line “quantum mechanics is weird”, there follows the no-one-understands-quantum-mechanics mantra.

Ball picks up on the bizarre nature of Feynman’s statement when he says that

“[a]t that point, no one alive knew more than Richard Feynman about quantum mechanics”.

He concludes: “What hope is there, then, for the rest of us?”

To be honest, I find Feynman’s remark rhetorical, as I suspect Ball does too. After all, it’s fairly well-known that Feynman didn’t have too much time for the interpretations of quantum mechanics, let alone for the philosophy of quantum mechanics. In other words, Feynman knew all (or at least most) of the relevant mathematics. “The trouble was”, as Ball puts it, “that’s all he could do.”

Philip Ball then applies more or less the same arguments found above to the specific and well-known case of Schrödinger’s cat.

Schrödinger’s Sexy Cat

First of all, Philip Ball tells us that

“in neither the Copenhagen nor the Many Worlds interpretation is the cat ‘simultaneously alive and dead’”.

In more detail, Ball also writes:

“I think Bohr might have said something along the lines that ‘Observation allows us to speak about the classical state of the cat. And look, it is a dead one!’.”

In other words, until we get information about the cat, we don’t know if it’s alive or dead. It’s not the case that it’s both alive and dead at one and the same time (i.e., before we gain that information). However, until we get that information, the cat may as well be both alive and dead…

But only in a manner of speaking!

Ball then offers up a more original take on this sexy-cat scenario.

Basically, why the hell are we talking about an alive and dead cat in the first place?

Sure, this was meant to be a colourful thought-experiment (i.e., against a certain take on quantum mechanics). However, it’s a thought-experiment which many people don’t actually take to be a thought-experiment at all. In Ball’s own words:

“In order to be able to talk about the [cat] scenario in quantum terms, we need to be able to express it in quantum terms. But we can’t, because ‘live cat’ and ‘dead cat’ are not well-defined quantum states.”

I don’t know about “well-defined quantum states”: a live cat and a dead cat (both together or separately) don’t seem to be quantum states at all. Perhaps that doesn’t matter. After all, what’s happening here is that we’re applying a quantum-mechanical situation (or possibility) to the “real world” — to a cat!

One problem here is thinking of quantum particles as classical particles which nonetheless behave in very non-classical ways. (Alternatively, the problem is thinking of quantum particles as being what Michael Brooks calls “objects” in the first place.) Many of the examples of quantum “weirdness” stem from that situation — at least those weird things which belong to the many and various interpretations of quantum mechanics. Yet whatever it is that quantum physicists deal with, it isn’t equivalent to classical objects. It’s not even equivalent — or similar — to particles of dust, sand or glass. [Here’s Carlo Rovelli playing down quantum weirdness.]

Thus, why should it be weird that a quantum x doesn’t behave like a classical object or even a classical particle? In reverse, if a classical object were to behave like a quantum x, then that would be weird…

So many people believe that quantum phenomena are weird mainly because they see them as being classical phenomena which nonetheless behave in very non-classical ways. Yet, in actual fact, we only have quantum phenomena behaving in quantum ways — just as classical phenomena behave in classical ways.

Of course, now there’s the problem of the Heisenberg cut. There’s also much dispute as to whether there is such a neat and tidy (to use the words of the physicist and science writer Brian Greene)“line in the sand” between the quantum realm and the classical realm.

But that’s another subject entirely…

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Note:

(1) Talking about “pop culture”…

In Christopher Nolan’s film Tenet, the character Neil mentions “parallel worlds”. So it’s worth making a distinction here between other dimensions, parallel worlds, and Hugh Everett’s many worlds.

Other dimensions are dimensions of our universe. (This is a fundamental part of string theory.) Parallel worlds, on the other hand, may be completely separate from our world.

So can there be “causal contact” between parallel worlds and our world?

This must surely mean that the only possibility that Tenet can have in mind is parallel dimensions, not parallel worlds. Indeed, when it comes to parallel worlds, it’s hard to make sense of the word “parallel” at all. These worlds simply can’t be parallel to our world.

So perhaps no one is expected to take the word “parallel” literally.

And just as a distinction has just been made between parallel dimensions and parallel worlds, so a distinction can also be made between the many worlds (i.e., of many-worlds theory) and the other “universes” of a multiverse. In the many-worlds interpretation, the possibility of causal — or other kinds of — contact between our world and other worlds is accepted — at least by some scientists. [See also brane cosmology.] However, when it comes to our universe and another universe (or a “bubble universe”) in a multiverse, that isn’t usually accepted by scientists. (Although there is some talk of “colliding” universes, etc.)