A conversation with Alain Aspect, Nobel Laureate and seminal experimenter in quantum physics

 You may or may not have heard of Alain Aspect (pronounced Ass-pay), but he’s a significant figure in the history of the development of quantum mechanics. Looking him up, I was surprised to learn he’s not much older than me. He was in his mid-thirties when he did his groundbreaking experiments: among the first to demonstrate Bell’s theorem in practice, not just in theory, and effectively proving that entanglement is non-local, meaning it breaks with special relativity.
 
This was almost 30 years after Einstein died, and effectively proved he was wrong regarding his views on entanglement. Having said that, it was Einstein who set the ball rolling with the famous 1935 paper titled, "Can Quantum-Mechanical Description of Physical Reality be Considered Complete?" that he co-wrote with Podolsky and Rosen, so better known as the EPR paper. Aspect jointly won the Nobel prize with John Clauser and Anton Zellinger for his definitive experimental contribution to that topic.
 
So I was surprised and very pleased to come across a 55 min interview with him by Brian Greene on YouTube, as part of a series. I read an interview with Aspect decades ago in a book co-edited by P C W Davies and Julian R Brown titled The Ghost in the Atom. It included interviews with other luminaries in the field like John Bell, Eugene Wigner, John Wheeler, David Deutsch and David Bohm, plus more.
 
Aspect is French, but his English is excellent. It’s unusual to find interviews with experimental physicists as opposed to theoretical physicists, and I would call it refreshing, because he tends not to elaborate or speculate beyond what the evidence tells him. Having said that, Greene presses him on what his intuition tells him, and even that is informative, because he keeps it simple.
 
While I was watching, I made some notes. I did not know that he was the first to produce isolated photons. If you go to roughly the 16-17m mark, he explains how he ‘split’ the wavefunction of the photon into ‘2 half wave packets’ (along 2 separate paths using beam splitters), which seems impossible for an individual photon. He says that the only way he can explain it is with non-locality. In his own words, ‘if I measure the wave packet on the right, the other wave packet on the left instantaneously collapses to zero.’
 
I can still remember when I was studying physics at university in the 70s, writing that a single photon could travel down 2 separate paths and being marked down for it. I’ve no idea where I read it, but Alain Aspect proved it in the 1980s.
 
When asked specifically by Greene, ‘Does the photon travel down both paths?’ Aspect answers unequivocally, ‘Yes’. But then he says ‘if he takes a measurement, it only appears on one side’. Curiously, when Greene asks him about the well known ‘measurement problem’ and what his ‘intuition’ is on that, Aspect said he doesn’t have one: ‘it’s a great mystery’, but then says it’s ‘irreversible’. Aspect then says that if you ask a cosmologist, they will say there is a wavefunction for the whole universe, where there is no measuring apparatus. I think that’s the nub of the issue. Non-local means instantaneous, which is Aspect’s description, and by my simplistic reasoning, this means the entangled particles must occupy the same ‘now’ in time, though no one ever mentions that because it’s a heresy. And if you have a wavefunction for the entire universe, then arguably you have the same ‘now’ throughout the universe, which is even more heretical.
 
The best part of this video is that Aspect takes us through the entire history of entanglement, starting with Schrodinger who coined the term and famously said that 'entanglement was the defining characteristic of quantum mechanics separate from classical physics'. I think, along with superposition, it’s what led me to believe the Universe obeys 2 sets of rules: quantum and classical. QM rules before decoherence of the wavefunction and classical physics rules after.
 
Naturally, Greene asks him about the MWI (Many Worlds Interpretation), which some argue overcomes the measurement problem. Aspect responds that ‘it’s a logical solution, but it’s absolutely not palatable’ (to him), while acknowledging it’s popular with many cosmologists. Just as an aside, Mithuna Yoganathan (from the Looking Glass Universe YouTube channel) specifically eschews the idea that the Universe obeys 2 sets of rules and that alone makes MWI attractive to her.
 
Interestingly, Aspect makes an analogy with the second law of thermodynamics (~21m) by pointing out that it can’t be derived from Newtonian mechanics, where everything is time-reversible. I’d say the same applies to chaos theory. A lot of laypeople are unaware that Schrodinger’s equation is deterministic, meaning it’s time-reversible, but the ‘measurement’ makes it irreversible. Paul Davies has made this same point. Aspect doesn’t articulate this, but what he’s saying is that the second law of thermodynamics is just as ‘radical’ (my word, not his) as QM when it comes to confounding our expectations based on previously known physics.
 
Greene says, ‘[QM] has been unreasonably successful and unreasonably effective’ to which Aspect replies, ‘Yes.’ This introduces their discussion of the 1935 EPR paper (~22m), and is arguably the most erudite and stimulating part of the discussion, because it logically leads to a discussion on John Bell’s theorem in some detail, which is what led to Aspect’s now equally famous experiment.
 
Another aside: on Quora I met a physicist, Ian Miller, with whom I had some interesting and convivial conversations. He’s one of the few people I know who disputes Bell’s Theorem, or at least its consequences, and has argued he can refute it. I’ve always respected him, simply because he knows more than me, and I too have some heretical ideas, plus I agree with him that in SR, it’s the ruler that changes and not the space it’s purporting to measure. Much later, I learned that Kip Thorne, of all people, made the point that it's impossible to tell the difference (between the ruler and the space its measuring) from the mathematics alone. Regarding Bell’s Theorem, Miller contends it’s just mathematical not physical, yet Alain Aspect would beg to differ.
 
One of the aspects of Bell’s theorem that many people don’t know is that Bell wanted to prove Einstein right, but effectively proved him wrong. Others have contended that Bell’s conclusion to his own discovery was that the universe must be super-deterministic, but I know he didn’t say that in his interview in the book I cited earlier, and Aspect doesn’t mention it either. I can understand, however, if you believe that the entangled particles don’t experience the same 'now', then superdeterminism is a logical conclusion. Hossenfelder is a keen advocate for superdeterminism.
 
In fact, Aspect claims that Bell was a ‘realist’, which I understand means that he believed what Aspect believes: there is an independent reality (to the observer) and non-locality is a feature of the Universe. I remember reading an article in New Scientist, where it was argued you can have realism or ‘locality’, but not both.
 
One of Aspect’s salient points is that the famous arguments between Bohr and Einstein became epistemological, meaning they were philosophical differences rather than differences in reasoning, but only when Einstein introduced entanglement of more than one particle. According to Aspect, when they were arguing about one particle, Bohr’s arguments were based on pure logic. As Greene points out, the EPR paper introduces the concept of ‘hidden variables’ which, according to Einstein is what would make quantum mechanics ‘complete’. Aspect claims that Bohr’s response to the EPR paper was purely philosophical. In hindsight, we know we had to wait for Bell to give it a mathematical framework, which would ultimately make it testable, which is what Aspect achieved.
 
Just on that point, it illustrates the necessary relationship between mathematics and physics. There is an intrinsic relationship between a mathematical model and the need to measure physical attributes to determine, not only if the mathematical model is valid, but what its limitations are. This, in effect, is how the physical sciences have advanced since Newton. We have reached a point where some of our mathematical models can’t be measured using the technology currently available (string theory, anyone?).
 
Aspect says that Bell found ‘you cannot have locality in a hidden variable theory rendering all the predictions of quantum mechanics in the EPR situation.’ (~28m) I find this interesting because I’ve come across people on YouTube (Hossenfelder) who claim that Bell’s Theorem doesn’t disprove hidden variables. They could be right, because Aspect is not saying that non-locality rules out hidden variables and Greene doesn’t ask him. But Aspect’s conclusion certainly rules out Einstein’s hope that hidden variables would save locality. Aspect gives credit to David Bohm for reformulating the EPR thought-experiment in terms of a dichotomy – spin-up or spin-down – and not a variable of position and velocity as per Einstein.
 
Aspect goes into some detail concerning his development of his experiment, including the work of others, which took him 7 years. According to Aspect, John Bell followed his work and respected his result; even saying publicly, ‘I am sorry for the result, but I respect it.’ Which says a lot.
 
At 41m Greene brings up MWI again, saying that many argue it solves non-locality. To which Aspect responds that, for him, accepting MWI is ‘worse’ than accepting non-locality. And Greene agrees.
 
Greene also raises the issue of free will, and Aspect’s response is amusing and, in his own words, ‘Simple. If I don’t have free will to adjust the knob on my apparatus, I stop being a physicist.’ Green smiles, yet doesn’t give his views which I’ve written about elsewhere. Greene is a free will sceptic, if not denier (like Hossenfelder). Aspect elaborates, arguing that the contrary position is: ‘If it’s written in the Great Book, ever since the Big Bang, it’s an explanation for everything.’ So, not a believer in superdeterminism.
 
He spends some time explaining how non-locality doesn’t contradict SR (special relativity) in as much as you can’t use it to signal FTL (faster-than-light), though I do in my science fiction, which is why it’s called science fiction. He points out rather cleverly that it’s solely because of the random nature of QM that you can’t use it to send a signal, because the measurement outcome is completely unknown and can’t be forced. Because it’s random, neither party can know the outcome.
 
Towards the end, he explains how he has become an ambassador for science, which I imagine he’d do brilliantly. He says he is an ‘optimist’ despite attacks on science, especially under America’s current administration.

Godel and Wittgenstein; same goal, different approach

 The current issue of Philosophy Now (Issue 169, Aug/Sep 2025) has as its theme, The Sources of Knowledge Issue, with a clever graphic on the cover depicting bottles of ‘sauces’ of 4 famous philosophers in this area: Thomas Kuhn, Karl Popper, Kurt Godel and Edmund Gettier. The last one is possibly not as famous as the other 3, and I’m surprised they didn’t include Ludwig Wittgenstein, though there is at least one article featuring him inside.
 
I’ve already written a letter to the Editor over one article Challenging the Objectivity of Science by Sina Mirzaye Shirkoohi, who is a ‘PhD Candidate at the Faculty of Administrative Sciences of the University Laval in Quebec City’; and which I may feature in a future post if it gets published.
 
But this post is based on an article titled Godel, Wittgenstein & the Limits of Knowledge by Michael D McGranahan, who has a ‘BS in Geology from San Diego State and an MS in Geophysics from Stanford, with 10 years [experience] in oil and gas exploration before making a career change’, without specifying what that career change is. ‘He is a lifelong student of science, philosophy and history.’ So, on the face of it, we may have a bit in common, because I’ve also worked in oil and gas, though in a non-technical role and I have no qualifications in anything. I’ve also had a lifelong interest in science and more recently, philosophy, but I’m unsure I would call myself a student, except of the autodidactic kind, and certainly not of history. I’m probably best described as a dilettante.
 
That’s a long runup, but I like to give people their due credentials, especially when I have them at hand. McGranahan, in his own words, ‘wants to explore the convergence of Godel and Wittgenstein on the limits of knowledge’, whereas I prefer to point out the distinctions. I should say up front that I’m hardly a scholar on Wittgenstein, though I feel I’m familiar enough with his seminal ideas regarding the role of language in epistemology. It should also be pointed out that Wittgenstein was one of the most influential philosophers of the 20th Century, especially in academia.
 
I will start with a quote cited by McGranahan: “The limits of my language mean the limits of my world.”
 
I once wrote a rather pretentious list titled, My philosophy in 24 dot points, where I paraphrase Wittgenstein: We think and conceptualise in a language. Axiomatically, this limits what we can conceive and think about. This is not exactly the same as the quote given above, and it has a subtly different emphasis. In effect, I think Wittgenstein has it back-to-front, based solely on his statement, obviously out-of-context, so I might be misrepresenting him, but I think it’s the limits of our knowledge of the world, that determines the limits of our language, rather than the other way round.
 
As I pointed out in my last post, we are continually creating new language to assimilate new knowledge. So, when I say, ‘this limits what we can conceive and think about’, it’s obvious that different cultures living in different environments will develop concepts that aren’t necessarily compatible with each other and this will be reflected in their respective languages. It’s one of the reasons all languages adopt new words from other languages when people from different cultures interact.
 
Humans are unique in that we think in a language. In fact, it’s not too much of a stretch to analogise it with software, remembering software is a concept that didn’t come into common parlance until after Wittgenstein died in 1951 (though Turing died in 1954).
 
To extend that metaphor, language becomes our ‘operating language’ for ‘thinking’, and note that it happens early in one’s childhood, well before we develop an ability to comprehend complex and abstract concepts. Just on that, arguably our exposure to stories is our first encounter with abstract concepts, if by abstract we mean entities that only exist in one’s mind.
 
I have a particular view, that as far as I know, is not shared with anyone else, which is that we have a unique ability to nest concepts within concepts ad infinitum, which allows us to create mental ‘black boxes’ in our thinking. To give an example, all the sentences I’m currently writing are made of distinct words, yet each sentence has a meaning that transcends the meaning of the individual words. Then, of course, the accumulation of sentences hopefully provides a cogent argument that you can follow. The same happens in a story which is arguably even more amazing, given a novel (like Elvene) contains close to 100k words, and will take up 8hrs of your life, but probably over 2 or 3 days. So we maintain mental continuity despite breaks and interruptions.
 
Wittgenstein once made the same point (regarding words and sentences), so that specific example is not original. Where my view differs is that I contend it also reflects our understanding of the physical world, which comprises entities within entities that have different physical representations at different levels. The example I like to give is a human body made up of individual cells, which themselves contain strands of DNA that provide the code for the construction and functioning of an individual. From memory, Douglas Hoffstadter made a similar point in Godel Escher Bach, so maybe not an original idea after all.
 
Time to talk about Godel. I’m not a logician, but I don’t believe you need to be to appreciate the far-reaching consequences of his groundbreaking theorem. In fact, as McGranahan points out, there are 2 theorems: Godel’s First Incompleteness Theorem and his Second Incompleteness Theorem. And it’s best to quote McGranahan directly:
 
Godel’s First Incompleteness Theorem proves mathematically that any consistent formal mathematical system within which a certain amount of elementary arithmetic can be carried out, is incomplete – meaning, there are one or more true statements that can be made in the language of the system which can neither be proved nor disproved in the system.
 
He then states the logical conclusion of this proof:
 
This finding leads to two alternatives: Alternative #1: If a set of axioms is consistent, then it is incomplete. Alternative #2: In a consistent system, not every statement can be proved in the language of that system.
 
Godel’s Second Incompleteness Theorem is simply this: No set of axioms can prove its own consistency.
 
It’s Alternative #2 that goes to the nub of the theorem: there are and always will be mathematical ‘truths’ that can’t be proved ‘true’ using the axioms of that system. Godel said himself that such truths (true statements) might be proved by expanding the system with new axioms. In other words, you may need to discover new mathematics to uncover new proofs, and this is what we’ve found in practice, and why some conjectures take so long to prove – like hundreds of years. The implication behind this is that our search for mathematical truths is neverending, meaning that mathematics is a neverending endeavour.
 
As McGranahan succinctly puts it: So knowing something is true, and proving it, are two different things.
 
This has led Roger Penrose to argue that Godel’s Theorems demonstrate the distinction between the human mind and a computer. Because a human mind can intuit a ‘truth’ that a computer can’t prove with logic. In a sense, he’s right, which is why we have conjectures like the ones I mentioned in my last post relating to prime numbers – the twin prime conjecture, the Goldbach conjecture and Riemann’s famous hypothesis. However, they also demonstrate the relationship between Godel’s Theorem and Turing’s famous Halting Problem, which Gregory Chaitin argues are really 2 manifestations of the same problem.
 
With each of those conjectures, you can create an algorithm to find all the solutions on a computer, but you can’t run the computer to infinity, so unless it ‘stops’, you don’t know if they’re true or not. The irony is that (for each conjecture): if it stops, it’s false and if it’s true, it never stops so it’s unknown. I covered this in another post where I argued that there is a relationship between infinity and the unknowable. The obvious connection here, that no one remarks on, is that Godel’s theorems only work because mathematics is infinite. If it was finite, it would be 'complete'. I came to an understanding of Godel’s Theorem through Turing’s Halting Problem, because it was easier to understand. A machine is unable to determine if a mathematical ‘truth’ is true or not through logic alone.
 
According to McGranahan, Wittgenstein said that “Tautology and contradiction are without sense.” He then said, “Tautology and contradiction are, however, nonsensical.” This implies that ‘without sense’ and ‘nonsensical’ have different meanings, “which illustrates the very language problem of which we speak” (McGranahan using Wittgenstein’s own language style to make his point). According to McGranahan, Wittgenstein then concluded: “that mathematics (if tautology and contradiction will be allowed to stand for mathematics), is nonsense.” (Parentheses in the original)
 
According to McGranahan, “…because in his logic, mathematical formulae are not bipolar (true or false) and hence cannot form pictures and elements and objects [which is how Wittgenstein defines language], and thus cannot describe actual states of affairs, and therefore, cannot describe the world.”
 
I feel that McGranahan doesn’t really resolve this, except to say: “There would seem to be a conflict… Who is right?” I actually think that if anyone is wrong, it’s Wittgenstein, though I admit a personal prejudice, in as much as I don’t think language defines the world.
 
On the other hand, everything we’ve learned about the world since the scientific revolution has come to us through mathematics, not language, and that was just as true in Wittgenstein’s time as it is now; after all, he lived through the 2 great scientific revolutions of quantum mechanics and relativity theory, both dependent on mathematics only discovered after Newton’s revolution.
 
The limits of our knowledge of the physical world are determined by the limits of our knowledge of mathematics (known as physics). And our language, while it ‘axiomatically limits what we can conceive and think about’, can also be (and continually is) expanded to adopt new concepts.

Reality, metaphysics, infinity

 This post arose from 3 articles I read in as many days: 2 on the same specific topic; and 1 on an apparently unrelated topic. I’ll start with the last one first.
 
I’m a regular reader of Raymond Tallis’s column in Philosophy Now, called Tallis in Wonderland, and I even had correspondence with him on one occasion, where he was very generous and friendly, despite disagreements. In the latest issue of Philosophy Now (No 169, Aug/Sep 2025), the title of his 2-page essay is Pharmaco-Metaphysics? Under which it’s stated that he ‘argues against acidic assertions, and doubts DMT assertions.’ Regarding the last point, it should be pointed out that Tallis’s background is in neuroscience.
 
By way of introduction, he points out that he’s never had firsthand experience of psychedelic drugs, but admits to his drug-of-choice being Pino Grigio. He references a quote by William Blake in The Marriage of Heaven and Hell: “If the doors of perception were cleaned, then everything would appear to man as it is, Infinite.” I include this reference, albeit out-of-context, because it has an indirect connection to the other topic I alluded to earlier.
 
Just on the subject of drugs creating alternate realities, which Tallis goes into in more detail than I want to discuss here, he makes the point that the participant knows that there is a reality from which they’ve become adrift; as if they’re in a boat that has slipped its moorings, which has neither a rudder nor oars (my analogy, not Tallis’s). I immediately thought that this is exactly what happens when I dream, which is literally every night, and usually multiple times.
 
Tallis is very good at skewering arguments by extremely bright people by making a direct reference to an ordinary everyday activity that they, and the rest of us, would partake in. I will illustrate with examples, starting with the psychedelic ‘trip’ apparently creating a reality that is more ‘real’ than the one inhabited without the drug.
 
The trip takes place in an unchanged reality. Moreover, the drug has been synthesised, tested, quality-controlled, packaged, and transported in that world, and the facts about its properties have been discovered and broadcast by individuals in the grip of everyday life. It is ordinary people usually in ordinary states of mind in the ordinary world who experiment with the psychedelics that target 5HT2A receptors.
 
He's pointing out an inherent inconsistency, if not outright contradiction (contradictoriness is the term he uses), that the production and delivery of the drug takes place in a world that the recipient’s mind wants to escape from.
 
And the point relevant to the topic of this essay: It does not seem justified, therefore, to blithely regard mind-altering drugs as opening metaphysical peepholes on to fundamental reality; as heuristic devices enabling us to discover the true nature of the world. (my emphasis)
 
To give another example of philosophical contradictoriness (I’m starting to like this term), he references Berkeley:
 
Think, for instance of those who, holding a seemingly solid copy of A Treatise Concerning the Principle of Human Knowledge (1710), accept George Berkeley’s claim [made in the book] that entities exist only insofar as they are perceived. They nevertheless expect the book to be still there when they enter a room where it is stored.
 
This, of course, is similar to Donald Hoffman’s thesis, but that’s too much of a detour.
 
My favourite example that he gives, is based on a problem that I’ve had with Kant ever since I first encountered Kant.
 
[To hold] Immanuel Kant’s view that ‘material objects’ located in space and time in the way we perceive them to be, are in fact constructs of the mind – then travel by train to give a lecture on this topic at an agreed place and time. Or yet others who (to take a well-worn example) deny the reality of time, but are still confident that they had their breakfast before their lunch.
 
He then makes a point I’ve made myself, albeit in a different context.
 
More importantly, could you co-habit in the transformed reality with those to whom you are closest – those who accept without question as central to your everyday life, and who return the compliment of taking you for granted?
 
To me, all these examples differentiate a dreaming state from our real-life state, and his last point is the criterion I’ve always given that determines the difference. Even though we often meet people in our dreams with whom we have close relationships, those encounters are never shared.
 
Tallis makes a similar point:
 
Radically revisionary views, if they are to be embraced sincerely, have to be shared with others in something that goes deeper than a report from (someone else’s) experience or a philosophical text.
 
This is why I claim that God can only ever be a subjective experience that can’t be shared, because it too fits into this category.
 
I recently got involved in a discussion on Facebook in a philosophical group, about Wittgenstein’s claim that language determines the limits of what we can know, which I argue is back-to-front. We are forever creating new language for new experiences and discoveries, which is why experts develop their own lexicons, not because they want to isolate other people (though some may), but because they deal with subject-matter the rest of us don’t encounter.
 
I still haven’t mentioned the other 2 articles I read – one in New Scientist and one in Scientific American – and they both deal with infinity. Specifically, they deal with a ‘movement’ (for want of a better term) within the mathematical community to effectively get rid of infinity. I’ve discussed this before with specific reference to UNSW mathematician, Norman Wildberger. Wildberger recently gained attention by making an important breakthrough (jointly with Dean Rubine using Catalan numbers). However, for reasons given below, I have issues with his position on infinity.
 
The thing is that infinity doesn’t exist in the physical world, or if it does, it’s impossible for us to observe, virtually by definition. However, in mathematics, I’d contend that it’s impossible to avoid. Primes are called the atoms of arithmetic, and going back to Euclid (325-265BC), he proved that there are an infinite number of primes. The thing is that there are 3 outstanding conjectures involving primes: the Goldbach conjecture; the twin prime conjecture; and the Riemann Hypothesis (which is the most famous unsolved problem in mathematics at the time of writing). And they all involve infinities. If infinities are no longer ‘allowed’, does that mean that all these conjectures are ‘solved’ or does it mean, they will ‘never be solved’?
                                                                                                                    
One of the contentions raised (including by Wildberger) is that infinity has no place in computations – specifically, computations by computers. Wildberger effectively argues that mathematics that can’t be computed is not mathematics (which rules out a lot of mathematics). On the other hand, you have Gregory Chaitin who points out that there are infinitely more incomputable Real numbers than computable Real numbers. I would have thought that this had been settled, since Cantor discovered that you can have countable infinite numbers and uncountable infinite numbers; the latter being infinitely larger than the former.
 
Just today I watched a video by Curt Jaimungal interviewing Chiara Marletto on ‘Constructor Theory’, which to my limited understanding based on this extract from a larger conversation, seems to be premised on the idea that everything in the Universe can be understood if it’s run on a quantum computer. As far as I can tell, she’s not saying it is a computer simulation, but she seems to emulate Stephen Wolfram’s philosophical position that it’s ‘computation all the way down’. Both of these people know a great deal more than me, but I wonder how they deal with chaos theory, which seems to drive the entire universe at multiple levels and can’t be computed due to a dependency on infinitesimal initial conditions. It’s why the weather can’t be forecast accurately beyond 10 days (because it can’t be calculated, no matter how complex the computer modelling) and why every coin-toss is independent of its predecessor (unless you rig it).
 
Note the use of the word, ‘infinitesimal’. I argue that chaos theory is the one phenomenon where infinity meets the real world. I agree with John Polkinghorne that it allows the perfect mechanism for God to intervene in the physical world, even though I don’t believe in an interventionist God (refer Marcus du Sautoy, What We Cannot Know).
 
I think the desire to get rid of infinity is rooted in an unstated philosophical position that the only things that can exist are the things we can know. This doesn’t mean that we currently know everything – I don’t think any mathematician or physicist believes that – but that everything is potentially knowable. I have long disagreed. And this is arguably the distinction between physics and metaphysics. I will take the definition attributed to Plato: ‘That which holds that what exists lies beyond experience.’ In modern science, if not modern philosophy, there is a tendency to discount metaphysics, because, by definition, it exists beyond what we experience in the real world. You can see an allusion here to my earlier discussion on Tallis’s essay, where he juxtaposes reality as we experience it with psychedelic experiences that purportedly provide a window into an alternate reality, where ‘everything would appear to man as it is, Infinite’. Where infinity represents everything we can’t know in the world we inhabit.
 
The thing is that I see mathematics as the only evidence of metaphysics; the only connection our minds have between a metaphysical world that transcends the Universe, and the physical universe we inhabit and share with innumerable other sentient creatures, albeit on a grain of sand on an endless beach, the horizon of which we’re yet to discern.
 
So I see this transcendental, metaphysical world of endless possible dimensions as the perfect home for infinity. And without mathematics, we would have no evidence, let alone a proof, that infinity even exists.

The edge of time

This is a contentious idea, despite the fact that we all believe we experience it all the time. Many physicists, including ones I admire, and whom I readily admit know a lot more than me (like Sabine Hossenfelder), believe that ‘now’ is an illusion; or (in the case of Paul Davies) that it requires a neurological explanation rather than a physical one. I will go further and claim there is an edge of time for the entire universe.
 
I made the point in a previous post that if you go on YouTube, you’ll find discussions with physicists who all have their own pet theories that are at odds with virtually everyone else, and to be honest, I can’t fault them, and I’m pleased that they’re willing to share their views.
 
Well, I’m not a physicist, but this is my particular heretical viewpoint that virtually no one else agrees with, with the additional caveat that they all have more expertise than me. They will tell you that I’m stuck in 19th Century physics, but I believe I can defend myself against that simple rebut.
 
During COVID lockdown in 2021, I did a series of online courses through New Scientist, including one on The Cosmos, where one of the lecturers was Chris Impey (Distinguished Professor, Department of Astronomy, University of Arizona) who made the point that the Universe has an ‘edge in time’, but not an edge in space. He might have used the word ‘boundary’ instead of ‘edge’, which would be more appropriate for space. In fact, it’s possible that space is infinite while time is finite, which means that the concept of spacetime might have limited application, but I’m getting ahead of myself.
 
The one other person I’ve read who might (partly) agree with me is Richard Muller, who cowrote a paper with Shaun Maguire, titled Now, and the Flow of Time, as well as a book, NOW; The Physics of Time, which I’ve read more than once. Basically, the edge of time on a cosmic scale is the edge of the Big Bang (which is still happening). What I’m saying is that there is a universal ‘Now’ for the entire universe, which is one of the most heretical ideas you can hold. According to modern physics, ‘Now’ is completely subjective and dependent on the observer – there is no objective Now, which is what I challenge.
 
There is a way in which this is correct, in that different observers in different parts of the Universe see completely different things (if they’re far enough apart) and would even see different horizons for the Universe. In fact, it’s possible that an observer who is over the horizon to us will see objects we can’t see, and of course, wouldn’t see us at all. This is because objects over the horizon are travelling away from us faster than the speed of light.
 
Because the speed of light is finite, the objects that we ‘observe’ millions or billions of light years away, are commensurately that much older than we are. And it follows from this logic, that if anyone could observe Earth from these same objects, they would see it equally old compared to what we see. This means that everyone sees a different now. This leads to the logical question: how could an objective ‘now’ exist? I like to invoke Kant that we cannot know the ‘thing-in-itself’, only our perception of it.
 
And I invoke Kant when I look at relativity theory, because it’s inherently an observer-dependent theory. I would contend that all physics theories are epistemic, meaning they deal with knowledge, rather than ontic, which is what is really there. Some argue that even space and time are epistemic, not ontic, but I disagree. The dimensions of space and time determine to a large extent what sort of universe we can live in. A point made by John Barrow in his book, The Constants of Nature.
 
In a not-so-recent post, I explained the famous pole-in-the-barn paradox, where 2 different observers see different things (in fact, measure different things) yet, in both cases, there is no clash between the pole and the barn (or in the example I describe, a spaceship and a tunnel). One of my conclusions is that it’s only the time that changes for the 2 observers, and not the space. Instead, they measure a different ‘length’ or ‘distance travelled’ by using their clocks as rulers. But it also implies that one of the observers is more ‘privileged’ than the other, which seems to contradict the equivalence principle. But I can make this claim because there is a reference frame for the entire universe, which is provided by the CMBR (cosmic microwave background radiation). This is not contentious, because we can even measure our velocity relative to it by using the Doppler effect, hence our velocity relative to the entire universe.
 
But there is another famous and simple experiment that provides evidence that there is an overall frame of reference for the Universe, which philosopher of science, Tim Maudlin, called ‘the most important experiment in physics’. If you were to go to the International Space Station and spin an object, it would be subject to the same inertial forces as it would on Earth. So what’s it spinning in reference to? The spaceship, its orbit around Earth, or the entire cosmos? I’d say, the entire universe, which is obviously not spinning itself, otherwise it would have a centre. Of course, Einstein knew this, and his answer was there is no absolute time or space but absolute spacetime.
 
I raised this earlier, because, if time is finite and space infinite, the concept of absolute spacetime breaks down, at least conceptually. But space doesn’t have to be infinite to have no boundary. In fact, it’s either open and infinite or closed and finite, albeit in 3 dimensions. To provide a relatable analogy, the Earth’s surface is finite and closed, but in 2 dimensions. Marcus du Sautoy made the point that, if the Universe is spatially infinite, we might never know.
 
The other point is that you could have clocks running at different rates dependent on where they are in the Universe, yet there could still be a universal Now. This is implicit in the famous twin paradox thought experiment. I like to point out that when the twins reunite they have lived different durations of time, yet agree where they are in time together. This means you can have a universal Now for the universe while disagreeing on its age; if you lived near a massive black hole, for instance.
 
In the same way observers can travel different distances to arrive at the same destination, they can travel different time intervals as well. In fact, they would agree they’ve travelled the exact same spacetime, which is why relativity theory argues you can only talk about spacetime combined rather than space and time separately. But I argue that it’s the clock that changes and not space, where the clock is the ruler for space.

The fly-in-the-ointment is simultaneity. According to relativity theory, simultaneity is completely dependent on the observer, but again, I invoke Kant. There could be an objective simultaneity that can’t be observed. I’ve written on this before, so I’ll keep it brief, but basically, you can have a ‘true’ simultaneity, if both the observer and the events are in the same frame of reference. And you can tell if you’re not, by using the Doppler effect. Basically, the Doppler effect tells you if the source of the signals (that are apparently simultaneous) are in the same frame of reference as you. If they’re not, then they’re not simultaneous, which infers there is an objective simultaneity. Whether this applies to the entire universe is another matter.

You may be familiar with this diagram.

 

 
I want to make a couple of points that no one else does. Firstly, everything outside the past light cone is unobservable (by definition), which means relativity theory can’t be applied (in practice), yet people do (in theory). As I said earlier, relativity is epistemic and all epistemic theories (or models) have limitations. In other words, I contend that there is an ontology outside the light cones that relativity theory can’t tell us anything about (I discuss this in more detail in a post appositely titled, The impossible thought experiment).
 
Secondly, the so-called ‘hypersurface’ is a fiction, or at best, a metaphor. Yet Brian Greene, to give one example, discusses it and graphically represents it as if it’s physically real. If ‘Now’ is the edge of the Big Bang, it suffuses the entire universe (even if it’s physically infinite), which means it’s impossible to visualise.
 
Let’s talk about another epistemic theory, quantum mechanics. In fact, the ontology of QM has been an open debate for more than a century. I recently watched a discussion between Matt (from PBS Space Time) and Mithuna Yoganathan (of Looking Glass Universe), which is excellent. It turns out they’re both from Melbourne, which is where I’m writing this. I figured Mithuna was Aussie, even though she’s based in London, but I didn’t pick Matt’s accent. I have to admit he sounds more Australian in his conversation with her. Towards the end of the video, they readily admit they get very speculative (meaning philosophical) but Mithuna provides compelling arguments for the multiple worlds interpretation (MWI) of QM. Personally, I argue that MWI doesn’t address the probabilities which is intrinsic to QM. Why are some worlds more probabilistic than others? If all outcomes happen in some universe somewhere, then they all have a probability of ONE in that universe. If there are an infinite number of universes then probabilities are nonsensical.
 
If you go to 37.10m of the video where Mithuna talks about the Schrodinger equation and the ‘2 rules’, I think she gets to the nub of the problem, and at 38.10 puts it into plain English. Basically, she says that there are either 2 rules for the Universe or you need to reject the ‘measurement’ or ‘collapse’ of the wave function, which means accepting MWI (the wave function continues in another universe), which she implies without saying. She says the 2 rules makes ‘the Copenhagen interpretation untenable’. I find this interesting, because I concluded many years ago that the Universe obeys 2 sets of rules.
 
My argument is that one set of rules, determined epistemically by the Schrodinger equation, describes the future and the other set of rules, which is classical physics and is determined by what we observe, describes the past.
 
A feature of QM, which separates it from classical physics, is entanglement and non-locality. Non-locality means it doesn’t strictly obey relativity theory, yet they remain compatible (because you can’t use entanglement to transmit information faster-than-light). In fact, Schrodinger himself said that “entanglement is the characteristic trait of quantum mechanics, the one that enforces its entire departure from classical lines of thought.” In other words, it obeys different rules to classical physics, with or without ‘measurement’.
 
MWI effectively argues that superposition exists in reality, albeit in parallel universes, whereas I contend that it only exists in the future. The wave function describes all of these possibilities, and via the Born rule, gives them probabilities. But when we observe it, which axiomatically puts it in the past, there is only ONE and there is no longer any superposition.
 
All physicists agree that entanglement, in principle, can apply to objects on opposite sides of the Universe. In fact, Schrodinger’s equation, in principle, can describe a wave function for the entire universe, which is why I’ve half-jokingly called it God’s equation, and have it tattooed on my arm.
 
I contend (though, as far as I know, no one agrees with me) that entanglement across the entire universe only makes sense if there is a universal Now for the entire universe. A Now that separates QM future superpositions (described by the wave function in Schrodinger’s equation) from past ‘observables’ in classical physics.

 

Addendum 1: this is one of the best and most erudite descriptions I've come across on entanglement and non-locality. Note how I avoided the word, 'explanation'. 

 Addendum 2: I've actually done a spacetime diagram depicting the twin paradox thought experiment using the scenario and numerical figures from this expositional post, which I provide in a thumbnail sketch (below). Basically, I wanted to demonstrate (to myself) that it's consistent with the proposition of a universal now. 

Note: it doesn't prove there is a universal now, and I'm pretty certain that all physicists would find fault with it, since it's such a heretical idea (refer last paragraph below). It's based on the assumption that there is an asymmetry between the 2 twins' perspectives, which is not in dispute, but explanations for the asymmetry are. My explanation is that there is an overall universe-size reference frame (refer main post) which is given physical manifestation by the CMBR (cosmic microwave background radiation). To put it in plain words, I don't believe it's the planet and solar system of the stay-at-home twin that flies off at fractional lightspeed, but the spaceship twin. 

As someone pointed out (a physicist I've lost touch with), it's the twin who has to use energy who is the one who experiences relativistic time-dilation, not the one who doesn't. Therefore, the spacetime diagram I drew reflects this, with the stay-at-home twin's time line going straight up and the space-faring twin's timeline going at a diagonal, though less than 45 degrees, which is the timeline for a light signal. Then I drew horizontal lines to indicate when the twins were experiencing the same 'now'. It was very consistent, while the 45 degree signals between them, give the correct answers as per my original exposition.

What physicists would find fault with is that the spacefaring twin traverses a different time interval and distance. But I contend that it travels the same distance while experiencing a different time. And the clock used to measure the interval would also measure a different distance, concordant with the different time. And if I’m correct, the twins would experience the same now, while experiencing different intervals of time. The proof of this, if I’m allowed to use that word, is the fact that they both experience the same ‘Now’, in both time and space, when they reunite. 

 

I invite anyone to tell me what's wrong with this, because it works when it shouldn't, based on my calculations using the Lorenz transformation for the space-faring twin.

 

 Addendum 3: There's a way in which the time experience is symmetrical but it's more to do with the Doppler effect than relativistic effects. For both twins they see time passing 3 times slower for their counterpart using their own clocks, but only on the outward journey of the space-faring twin. In essence (using the example in the diagram), the stay-at-home twin ages 45 years while he 'sees' his counterpart age 15 years. On the other hand, the space-faring twin ages 15 years while he 'sees' his counterpart age only 5 years (refer my original post). However this is reversed on the return trip, when each twin sees their counterpart age 3 times quicker. For the stay-at-home twin, he ages another 5 years while his counterpart ages another 15 years. And, for the space-faring twin, he ages 15 years while he sees his counterpart age another 45 years. This is totally consistent with the spacetime diag depicted above.

 

Each twin has their own true time, τ (called tau), which I will designate τ₁ and τ₂ for the earth-bound twin and space-faring twin, respectively. And then I use γ (gamma, representing the Lorenz transform) to convert from τ₁ to τ₂ (see the original post for the maths). I think that's the simplest way to formulate it, and that gives you the diag above, and is what one would expect to observe if the experiment could be done for real, which of course, it can't. However, we know time dilation works when we use particle accelerators (exactly as predicted by Einstein), so we would expect it to work in space if we could travel that fast.

The infinite monkey theorem and the anthropic principle

 I was originally going to write this as an addendum to my not-so-recent post, The problem with physics, but it became obvious that it deserved a post of its own.
 
It so happens that Sabine Hossenfelder has posted a video relevant to this topic since I published that post. She cites a paper by some renowned physicists, including Lawrence Krauss, that claims a theory of everything (TOE) is impossible. Not surprisingly, Godel’s Incompleteness Theorem for mathematics forms part of their argument. In fact, the title of their paper is Quantum gravity cannot be both consistent and complete, which is a direct reference to Godel. This leads to a discussion by Sabine about what constitutes ‘truth’ in physics and the relationship between mathematical models, reality and experiments. Curiously, Australian-American, world-renowned mathematician, Terence Tao, has a similar discussion in a podcast with Lex Fridman (excellent series, btw).
 
Tao makes the point that there are 3 aspects to this, which are reality, our perception of it, and the mathematical models, and they have been converging over centuries without ever quite meeting up in a final TOE. Tao comes across as very humble, virtually egoless, yet he thinks string theory is 'out of fashion', which he has worked on, it should be pointed out. Tao self-describes himself as a ‘fox’, not a ‘hedgehog’, meaning he has diverse interests in maths, and looks for connections between various fields. A hedgehog is someone who becomes deeply knowledgeable in one field, and he has worked with such people. Tao is known for his collaborations.
 
But his 3 different but converging perspectives is consistent with my Kantian view that we may never know the thing-in-itself, only our perception of it, while such perceptions are enhanced by our mathematical interpretations. We use our mathematical models as additional, complementary tools to the physical tools, such as the LHC and the James Webb telescope.
 
Tao gives the example of the Earth appearing flat to all intents and purposes, but even the ancient Greeks were able to work out a distance to the moon orbiting us, based on observations (I don’t know the details). Over time, our mathematical theories tempered by observation, have given us a more accurate picture of the entire observable universe, which is extraordinary.
 
I’ve made the point that all our mathematical models have limitations, which makes me sceptical that a 'final' TOE will be possible, even before I’d heard of the paper that Sabine cited. But, while mathematics provides epistemological limits on what we can know, I also believe it provides ontological limits on what’s possible. The Universe obeys mathematical rules at every level we’ve observed it. The one possible exception being consciousness – I am sceptical we will ever find a mathematical model for consciousness, but that’s another topic.
 
Tao doesn’t mention the anthropic principle – at least in the videos I’ve watched – but he does at one point talk about the infinite monkey theorem, which is a real mathematical theorem and not just a thought experiment or a pop-culture meme. Basically, it says that if you have an infinite number of monkeys bashing away on typewriters they will eventually type out the complete works of Shakespeare, despite our intuitive belief that this should be impossible.
 
As Tao points out, the salient feature of this thought experiment is infinity. In his own words, ‘Infinity absolves a lot of sins’. In the real world, everything we’re aware of is finite, including the observable universe. We’ve no idea what’s beyond the horizon, and, if it’s infinite, then it may remain forever unknowable, as pointed out by Marcus du Sautoy in his excellent book, What We Cannot Know. Tao makes the point that there is a ‘finite’ limit where this extraordinary but not impossible task becomes a distinct possibility. And I would argue that this applies to the evolution of complex life, which eventually gave rise to us. An event that seems improbable, but becomes possible if the Universe is big and old enough, while remaining finite, not infinite. To me, this is another example of how mathematics determines the limits of what’s possible.

Tao has his own views on a TOE or a theory for quantum gravity, which is really what they’re talking about. I think it will require a Kuhnian revolution as I concluded in my second-to-last post, and like all resolutions, it will uncover further mysteries.

 

The problem with physics

 This title could be easily misconstrued, as it gives the impression that there is only one problem in physics and if we could solve that, everything would be resolved and there would be nothing left to understand or explain. Anyone familiar with this blog will know that I don’t believe that at all, so I need to unpack this before I even start.
 
And you might well ask: if I know there are a number of problems in physics, why didn’t I make that clear in the title? You see, I’ve embedded a question in the title that I want you to ask.
 
I’ve been watching a number of videos over a period of time, many of them on Curt Jaimungal’s channel, Theories of Everything, where he talks to a lot of people, much cleverer than me, some of whom have the wildest theories in science, and physics in particular. If one takes John Wheeler’s metaphor of an island of knowledge in an infinite sea of ignorance, they are all building theories on the shoreline of that island. I like to point out (as a personal ego-boost) that I came up with that metaphor before I knew Wheeler had beaten me to it.
 
To give just one example that seems totally ‘out there’, Emily Adlam proposes her ‘Sudoku universe’ where everything exists at once. She’s not alone, because it’s not dissimilar to Sabine Hossenfelder’s position, though she uses different arguments. Of course, both her and Sabine are far more knowledgeable on these topics than me, so while I disagree, I acknowledge I don’t have the chops to take them on in a proper debate. Another example is Claudia de Rahm, whom I’ve referenced before, who thinks that gravitons may have mass, which would seem to contradict the widely held belief that gravitational waves travel at the speed of light. She has discussions with Curt, that once again, are well above my level of knowledge on this topic. 

Another person he interviews is Avshalom Elitzur, who even makes statements I actually agree with. In this video, he argues that space-time is created when the wave function collapses. It’s a very unorthodox view but it’s consistent with mine and Freeman Dyson’s belief that QM (therefore the wave function) can only describe the future. However, he also has a radical idea that the ‘creation’ of space may be related to the creation of charge, because if the space is created between the particles, they repel, and if it’s created outside, they attract. I admit I have problems with this, even though it took Curt to clarify it. Richard Muller (whose book, NOW, I’ve read) also argues that space may be created along with time. Both of these ideas are consistent with the notion that the Big Bang is still in progress – both time and space are being created as the Universe expands.
 
So there are lots of problems, and the cleverest people on the planet, including many I haven’t mentioned like Roger Penrose and Sean Carroll, all have their own pet theories, all on the shoreline of Wheeler’s metaphorical island.
 
But the island metaphor provides a clue to why the problem exists, and that is that they are all just as philosophical as they are scientific. Sabine attempted to address this in 2 books she wrote: Lost in Math and Existential Physics; both of which I’ve read. But there are 2 levels to this problem when it comes to physics, which are effectively alluded to in the titles of her books. In other words, one level is philosophical and the next level is mathematical.
 
All of the people I mentioned above, along with others I haven’t mentioned, start with a philosophical position, even if they don’t use that term. And all physics theories are dependent on a mathematical model. There is also arguably a third level, which is experimental physics, and that inexorably determines whether the model, and hence the theory, is accurate.
 
But there is a catch: sometimes the experimental physics has proven the ‘theory’ correct, yet the philosophical implications are still open to debate. This is the case with quantum mechanics (QM), and has been for over a century. As Sabine pointed out in a paper she wrote, our dilemmas with QM haven’t really changed since Bohr’s and Einstein’s famous arguments over the Copenhagen interpretation, which are now almost a century old.
 
Some would argue that the most pertinent outstanding ‘problem’ in physics is the irreconcilability of gravity, or Einstein’s general theory of relativity (GR), and QM. Given the problems we have with dark matter and dark energy, which are unknown yet make up 95% of the Universe, I think we are ripe for another Kuhnian revolution in physics. And if that’s true, then we have no idea what it is.

Time again

 This is a topic I’ve written about before, many times, but I’m returning to it on this occasion because of a video I watched by Curt Jaimungal, whom I can recommend. He’s smart and interviews people who are even smarter, and he has a particular penchant for interviewing people with unorthodox ideas, but with the knowledge to support them. He also has the good sense to let them do nearly all of the talking. He rarely interjects and when he does, it’s pertinent and tends to not interrupt the flow. I’ve sometimes been annoyed by interviewers cutting someone off when they were about to say something that I was interested in hearing. I could never accuse Curt of that.
 
In this case he’s interviewing Avshalom Elitzur, whom I’ve also referenced before. He’s a bit of an iconoclast – my favourite type of person, even if I disagree with them. If I’m to be fair, I’d have to include Donald Hoffman in that category, though I’ve been a harsh critic in the past. Having said that, I’ve noticed that Donald has changed his approach over the 8 or so years I’ve been following him. As I’ve said before, it’s important to follow the people you disagree with as well as those you agree with, especially when they have knowledge or expertise that you don’t.
 
Elitzur discusses three or more topics, all related to Einstein’s theories of relativity, but mostly the special theory. He starts off by calling out (my phrase) what he considers a fundamental problem that most physicists, if not all (his phraseology) ignore, which is that time is fundamentally different to space, because time changes in a way that space does not. What’s more we all experience this, with or without a scientific theory to explain it. He gives the example of how another country (say, Japan) still exists even though you don’t experience it (assuming you’re not Japanese). If you are in Japan, make it Australia. On the other hand, another time does not exist in the same way (be it past or present), yet many physicists talk about it as if it does. I discussed this in some depth, when I tackled Sabine Hoffenfelder’s book, Existential Physics; A Scientist’s Guide to Life’s Biggest Questions.
 
Elitzur raises this at both the start and towards the end of the video, because he thinks it’s distorting how physicists perceive the world. Specifically, Einstein’s block-universe, where all directions in time exist simultaneously in the same way that all directions in space exist all at once. He mentions that Penrose challenges this and so did Paul Davies once, but not now. In fact, I challenge Davies’ position in another post I wrote after reading his book, The Demon in the Machine. Elitzur makes the point that challenging this is considered naïve but he also makes another point much more dramatically. He says that for Einstein, the ‘future cut’ in time is ‘already there’ (10.50) and consequently said, ‘…has the same degree of reality as the present cut and the past cut. Are you okay with that?’ His exact words.
 
He recounts the famous letter that Einstein wrote to the family of a good friend who had just passed away, and only 4 weeks before Einstein himself passed away (I didn’t know that before Elitzur told me), from which we have this much quoted extract: ‘The past, present and future is only a stubbornly persistent illusion.’ Davies also used this quote in his abovementioned book.
 
I’m going to talk about last what Elitzur talked about early, if not quite first, which is the famous pole-in-the-barn thought experiment. Elitzur gives a good explanation, if you haven’t come across it before, but I’ll try because I think it’s key to understanding the inherent paradox of special relativity, and also providing an explanation that reconciles with our perception of reality.
 
It's to do with Lorenz-contraction, which is that, for an observer, an object travelling transversely to their field of vision (say horizontally) shortens in the direction of travel. This is one of those Alice and Bob paradoxes, not unlike the twin paradox. Let us assume that Alice is in a space ship who goes through a tunnel with doors at both ends, so that her ship fits snugly inside with no bits hanging out (like when both are stationary). And Bob operates the doors, so that they open when Alice arrives, close when she is inside and open to allow her to leave. From Bob’s perspective, Alice’s spaceship is shorter than the tunnel, so she fits inside, no problem. Also, and this is the key point (highlighted by Elitzur): according to Bob, both doors open and close together – there is no lag.
 
The paradox is resolved by relativity theory (and the associated mathematics), because, from Alice’s perspective, the doors don’t open together but sequentially. The first door opens and then closes after she’s passed through it, and the second door opens slightly later and remains open slightly longer so that the first door closes behind her before she leaves the tunnel. In other words, both doors are closed while she’s in the tunnel, but in such a way that they’re not closed at the same time, therefore her spaceship doesn’t hit either of them. This is a direct consequence of simultaneity being different for Alice. If you find that difficult to follow, watch the video
 
I have my own unorthodox way of resolving this, because, contrary to what everyone says, I think there is a preferred frame of reference, which is provided by ‘absolute spacetime’. You can even calculate the Earth’s velocity relative to the overall spacetime of the entire universe by measuring the Doppler shift of the CMBR (cosmic microwave background radiation). This is not contentious – Penrose and Davies both give good accounts of this. It’s also related to what Tim Maudlin called, the most important experiment in physics, which is Newton spinning a bucket of water and observing the concave surface of the water due to the centrifugal force, and then asking: what is it spinning in reference to? Answer: the entire universe.
 
You might notice that when someone describes or explains the famous twin paradox, they only ever talk about the time difference – they rarely, if ever, talk about the space contraction. Personally, I don’t think space contracts in reality, but time duration does. If you take an extreme example, you could hypothetically travel across the entire galaxy in your lifetime, which means, from your perspective, the distance travelled would be whole orders of magnitude shorter. This can be resolved if it’s the ruler measuring the distance that changes and not the distance. In this case, the clock acts as a ruler. Kip Thorne has commented on this without drawing any conclusions.
 
This same logic could be applied to the spaceship and the tunnel. For Alice, it appears shorter, but she’s the one ‘measuring’ it. If one extends this logic, then I would argue that there is a ‘true simultaneity’, experienced by Bob in this case, because he is in the same frame of reference as the tunnel and the doors. I need to point out that, as far as I know, no one else agrees with me, including Elitzur. However, it’s consistent with my thought experiment about traversing the galaxy: time contracts but space doesn't.
 
I’ve raised this before, but I believe that there is an independent reality to all observers, and this is consistent with Kant’s famous dictum that there is a ‘thing-in-itself’ that we may never perceive. In other words, relativity can only tell us about what we observe, which leaves open the possibility that there is a reality that one observer has a better perception of than another. It’s possible that while ‘time passed’ is observer-dependent, space is not, but only the observer’s perception of it.
 
This is also consistent with Elitzur’s overall thesis and core argument that space and time are different. It’s also consistent with the idea that there is a frame of reference for the entire universe, which I argue is what general relativity (GR) gives us. And in fact, we observe that local frames of reference can actually travel faster than light, which is why the observable universe has a horizon: there are parts of the Universe receding from us faster than light.
 
There is another aspect of this that Elitzur doesn’t bring up, and that is that there is an edge in time for the Universe, but no boundary in space. I find it curious that, if physicists bring this up at all, they tend to gloss over it and not provide a satisfactory resolution. You see, it conflicts with the idea, inherent in the block-universe model, that there is no ‘now’.
 
Curt introduces ‘now’ towards the end of the video, but only in reference to the ‘flow’ of time that we all experience. Again, I’m a heretic in that I believe there is a universal now for the entire universe.
 
And while I don’t think it explains entanglement and non-locality in QM, it’s consistent with it. Entanglement works across space and time independently of relativistic causality, without breaking the relativistic rule that you can’t send information faster than light.
 
As it happens, there is another video by Curt with Tim Maudlin, an American philosopher of science, whom Curt introduces as ‘bringing some sober reality to this realm of quantum confusion and mysticism.’ In particular, Maudlin gives an excellent exposition of Bell’s famous theorem, and debunks the claim that it questions whether there is ‘reality’. In other words, it’s often formulated as: you can accept non-locality or you can accept reality, but you can’t have both. Just to clarify, ‘locality’ means local phenomena that obey SR (special relativity) as I’ve discussed above.
 
Maudlin argues quite cogently that you only need 2 assumptions for Bell’s theorem to make sense and neither of them break reality. The main assumption is that there is ‘statistical independence’, which he explains by giving examples of medical controlled experiments (for example, to test if tobacco causes lung cancer). It just means that random really does mean random, which gives true independence.
 
The only other assumption is that we can have non-locality, which means you can have a connection or relationship between events that is not dependent on special relativity. Numerous experiments have proven this true.
 
Maudlin challenges Sabine’s contention that Bell’s Theorem can only be explained by ‘superdeterminism’, which is another name for Einstein’s block-universe, which started this whole discussion. Sabine is so convinced by superdeterminism, she has argued that one day everyone will agree with her. This of course has implications for free will and is central to Elitzur’s argument that the future does not exist in the same way as the present or even the past, which is fixed. And that’s his point. Sabine’s and most physicist’s view on all this is that what we experience must be an illusion: there is no now, no flow of time, and no free will.

Addendum 1: I came across another video by Curt with Jacob Barandes, that came out after I posted this. Jacob is a Harvard scientist, who has done a series of videos with Curt. It's relevance to this topic is that he talks about space-time in GR and how, unlike Newtonian physics, and even SR, you can't tell which direction time and space have. And this axiomatically creates problems when you try to quantumise it (to coin a term). I think the superposition of a gravitational field creates its own problems (not discussed). He then goes on to conjecture that there should be an intermediate step in trying to derive a quantum field theory of gravity, and that is to do probabilities on gravity. He acknowledges this is a highly speculative idea.

He then goes on to talk about 'expectation values', which is the standard way physicists have tried to model QFT (quantum field theory) on to spacetime, and is called 'semi-classical gravity'. Viktor T Toth (on Quora) says about this: …it is hideously inelegant, essentially an ad-hoc averaging of the equation that is really, really ugly and is not derived from any basic principle that we know. Nevertheless, Toth argues that it 'works'. Barandes goes further and says it's based on a fallacy (watch the video if you want an elaboration). To quote Toth again: We can do quantum field theory just fine on the curved spacetime background of general relativity. What we have so far been unable to do in a convincing manner is turn gravity itself into a quantum field theory.

I tend to agree with Freeman Dyson, who contends that they are not compatible in theory or in nature. In other words, he argues that quantum gravity is a chimera. Dyson also argues that QM can't describe past events; so, if that's true, quantum gravity is attempting to describe spacetime in its future. Arguably, this is what happens the other side of the event horizon of a black hole, where space itself only exists in one's future, which leads to the singularity. 

Addendum 2: Since posting this I've watched a lot of other videos, many of them by Curt, which may become the subject of a future post. But I just wanted to reference this one with Emily Adlam, who has a view completely opposite to the one expressed in my post above. She's developed what she calls the 'Sudoku universe', or the 'all at once' universe. The analogy with Sudoku is that the outcome is already 'known' and you can start anywhere at all - there is no progression from a fixed starting point to a fixed end point. This video is 1hr 19m, and I need to point out that she knows a lot more about this subject than I do, and so does Curt. Curt had obviously read all her papers relevant to this and knew exactly what to ask her. I know that if I was to go one-on-one with her, I could never argue at her level. I intend, at some point, to write another post where I discuss points-of-view of various physicists that are all driven more by philosophy than science.

Have we forgotten what ‘mind’ means?

 There is an obvious rejoinder to this, which is, did we ever know what ‘mind’ means? Maybe that’s the real question I wanted to ask, but I think it’s better if it comes from you. The thing is that we have always thought that ‘mind’ means something, but now we are tending to think, because we have no idea where it comes from, that it has no meaning at all. In other words, if it can’t be explained by science, it has no meaning. And from that perspective, the question is perfectly valid.
 
I’ve been watching a number of videos hosted by Curt Jaimungal, whom I assume has a physics background. For a start, he’s posted a number of video interviews with a ‘Harvard scientist’ on quantum mechanics, and he provided a link (to me) of an almost 2hr video he did with Sabine Hossenfelder, and they talked like they were old friends. I found it very stimulating and I left a fairly long comment that probably no one will read.
 
Totally off-topic, but Sabine’s written a paper proposing a thought-experiment that would effectively test if QM and GR (gravity) are compatible at higher energies. She calculated the energy range and if there is no difference to the low energy experiments already conducted, it effectively rules out a quantum field for gravity (assuming I understand her correctly). I expressed my enthusiasm for a real version to be carried out, and my personal, totally unfounded prediction that it would be negative (there would be no difference).
 
But there are 2 videos that are relevant to this topic and they both involve Stephen Wolfram (who invented Mathematica). I’ve referenced him in previous posts, but always second-hand, so it was good to hear him first-hand. In another video, also hosted by Jaimungal, Wolfram has an exchange with Donald Hoffman, whom I’ve been very critical of in the past, even saying that I found it hard to take him seriously. But to be fair, I need to acknowledge that he’s willing to put his ideas out there and have them challenged by people like Stephen Wolfram (and Anil Seth in another video), which is what philosophy is all about. And the truth is that all of these people know much more about their fields than me. I’ll get to the exchange with Hoffman later.
 
I have the impression from Gregory Chaitin, in particular, that Wolfram argues that the Universe is computable; a philosophical position I’ve argued against, mainly because of chaos theory. I’ve never known Wolfram to mention chaos theory, and he certainly doesn’t in the 2 videos I reference here, and I’ve watched them a few times.
 
Jaimungal introduces the first video (with Wolfram alone) by asking him about his ‘observer theory’ and ‘what if he’s right about the discreteness of space-time’ and ‘computation underlying the fundament?’ I think it’s this last point which goes to the heart of their discussion. Wolfram introduces a term called the Ruliad, which I had to look up. I came across 2 definitions, both of which seem relevant to the discussion.
 
A concept that describes all possible computations and rule-based systems, including our physical universe, mathematics, and everything we experience.
 
A meta-structural domain that encompasses every possible rule-based system, or computational eventuality, that can describe any universe or mathematical structure.
 
Wolfram confused me when he talked about ‘computational irreducibility’, which infers that there are some things that are not computable, to which I agree. But then later he seemed to argue that everything we can know is computable, and things we don’t know now are only unknowable because we’re yet to find their computable foundation. He argues that there are ‘slices of reducible computability’ within the ‘computational irreducibility’, which is how we do mathematical physics.
 
Towards the end of the video, he talks specifically about biology, saying, ‘there is no grand theory of biology’, like we attempt in physics. He has a point. I’ve long argued that natural selection is not the whole story, and there is a mystery inherent in DNA, in as much as it’s a code whose origin and evolvement is still unknown. Paul Davies attempted to tackle this in his book, The Demon in the Machine, because it’s analogous to software code and it’s information based. This means that it could, in principle, be mathematical, which means it could lead to a biological ‘theory of everything’, which I assume is what Wolfram is claiming is lacking.
 
However, I’m getting off-track again. At the start of the video, Wolfram specifically references the Copernican revolution, because it was not just a mathematical reformulation, but it changed our entire perspective of the Universe (we are not at the centre) without changing how we experience it (we are standing still, with the sky rotating around us). At the end of the day, we have mathematical models, and some are more accurate than others, and they all have limitations – there is no all-encompassing mathematical TOE (Theory of Everything). There is no Ruliad, as per the above definitions, and Wolfram acknowledges that while apparently arguing that everything is computable.
 
I find it necessary to bring Kant into this, and his concept of the ‘thing-in-itself’ which we may never know, but only have a perception of. My argument, which I’ve never seen anyone else employ, is that mathematics is one of our instruments of perception, just like our telescopes and particle accelerators and now, our gravitational wave detectors. Our mathematical models, be they GR (general relativity), QFT or String Theory, are perceptual and conceptual tools, whose veracity are ultimately determined by empirical evidence, which means they can only be applied to things that can be measured. And I think this leads to an unstated principle that if something can’t be measured it doesn’t exist. I would put ‘mind’ in that category.
 
And this allows me to segue into the second video, involving Donald Hoffman, because he seems to argue that mind is all that there is, and it has a mathematical foundation. He put forward his argument (which I wrote about recently) that, using Markovian matrices, he’s developed probabilities that apparently predict ‘qualia’, which some argue are the fundaments of consciousness. Wolfram, unlike the rest of us, actually knows what Hoffman is talking about and immediately had a problem that his ‘mathematical model’ led to probabilities and not direct concrete predictions. Wolfram seemed to argue that it breaks the predictive chain (my terminology), but I confess I struggled to follow his argument. I would have liked to ask: what happens with QM, which can only give us probabilities? In that case, the probabilities, generated by the Born Rule, are the only link between QM and classical physics – a point made by Mark John Fernee, among others.
 
But going back to my argument invoking Kant, it’s a mathematical model and not necessarily the thing-in-itself. There is an irony here, because Kant argued that space and time are a priori in the mind, so a projection, which, as I understand it, lies at the centre of Hoffman’s entire thesis. Hoffman argues that ‘spacetime is doomed’ since Nima Arkani-Hamed and his work on amplituhedrons, because (to quote Arkani-Hamed): This is a concrete example of a way in which the physics we normally associate with space-time and quantum mechanics arises from something more basic. In other words, Arkani-Hamed has found a mathematical substructure or foundation to spacetime itself, and Hoffman claims that he’s found a way to link that same mathematical substructure to consciousness, via Markovian matrices and his probabilities.
 
Hoffman analogises spacetime to wearing a VR headset and objects in spacetime to icons on a computer desktop, which seems to infer that the Universe is a simulation, though he’s never specifically argued that. I won’t reiterate my objections to Hoffman’s fundamental idealism philosophy, but if you have a mathematical model, however it’s formulated, its veracity can only be determined empirically, meaning we need to measure something. So, what is he going to measure? Is it qualia? Is it what people report what they think?
 
No. According to Hoffman, they can do empirical tests on spacetime (so not consciousness per se) that will determine if his mathematical model of consciousness is correct, which seems a very roundabout way of doing things. From what I can gather, he’s using a mathematical model of consciousness that’s already been developed (independently) to underpin reality, and then testing it on reality, thereby implying that consciousness is an intermediate step between the mathematical model and the reality. His ambition is to demonstrate that there is a causal relationship between consciousness and reality, when most argue that it’s the other way around. I return to this point below, with Wolfram’s response.
 
Wolfram starts off in his interaction with Hoffman by defining the subjective experience of consciousness that Hoffman has mathematically modelled and asking, can he apply that to an LLM (like ChatGPT, though he doesn’t specify) and therefore show that an LLM must be conscious? Wolfram argues that such a demonstration would categorically determine the ‘success’ (his term) of Hoffman’s theory, and Hoffman agreed.
 
I won’t go into detail (watch the video) but Hoffman concludes, quite emphatically, that ‘It’s not logically possible to start with non-conscious entities and have conscious agents emerge’ (my emphasis, obviously). Wolfram immediately responded (very good-naturedly), ‘That’s not my intuition’. He then goes on to say how that’s a Leibnizian approach, which he rejected back in the 1980s. I gather that it was around that time that Wolfram adopted and solidified (for want of a better word) his philosophical position that everything is ultimately computable. So they both see mathematics as part of the ‘solution’, but in different ways and with different conclusions.
 
To return to the point I raised in my introduction, Wolfram starts off in the first video (without Hoffman), that we have adopted a position that if something can’t be explained by science, then there is no other explanation – we axiomatically rule everything else out - and he seems to argue that this is a mistake. But then he adopts a position which is the exact opposite: that everything is “computational all the way down”, including concepts like free will. He argues: “If we can accept that everything is computational all the way down, we can stop searching for that.” And by ‘that’ he means all other explanations like mysticism or QM or whatever.
 
My own position is that mathematics, consciousness and physical reality form a triumvirate similar to Roger Penrose’s view. There is an interconnection, but I’m unsure if there is a hierarchy. I’ve argued that mathematics can transcend the Universe, which is known as mathematical Platonism, a view held by many mathematicians and physicists, which I’ve written about before.
 
I’m not averse to the view that consciousness may also exist beyond the physical universe, but it’s not something that can be observed (by definition). So far, I’ve attempted to discuss ‘mind’ in a scientific context, referencing 2 scientists with different points of view, though they both emphasise the role of mathematics in positing their views.
 
Before science attempted to analyse and put mind into an ontological box, we knew it as a purely subjective experience. But we also knew that it exists in others and even other creatures. And it’s the last point that actually triggered me to write this post and not the ruminations of Wolfram and Hoffman. When I interact with another animal, I’m conscious that it has a mind, and I believe that’s what we’ve lost. If there is a collective consciousness arising from planet Earth, it’s not just humans. This is something that I’m acutely aware of, and it has even affected my fiction.
 
The thing about mind is that it stimulates empathy, and I think that’s the key to the long-term survival of, not just humanity, but the entire ecosystem we inhabit. Is there a mind beyond the Universe? We don’t know, but I would like to think there is. In another recent post, I alluded to the Hindu concept of Brahman, which appealed to Erwin Schrodinger. You’d be surprised how many famous physicists were attracted to the mystical. I can think of Pauli, Einstein, Bohr, Oppenheimer – they all thought outside the box, as we like to say.
 
Physicists have no problem mentally conceiving 6 or more dimensions in String Theory that are ‘curled up’ so miniscule we can’t observe them. But there is also the possibility that there is a dimension beyond the universe that we can’t see. Anyone familiar with Flatland by Edwin Abbott (a story about social strata as much as dimensions), would know it expounds on our inherent inability to interact with higher dimensions. It’s occurred to me that consciousness may exist in another dimension, and we might ‘feel’ it occasionally when we interact with people who have died. I have experienced this, though it proves nothing. I’m a creative and a neurotic, so such testimony can be taken with a grain of salt.
 
I’ve gone completely off-track, but I think that both Wolfram and Hoffman may be missing the point, when, like many scientists, they are attempting to incorporate the subjective experience of mind into a scientific framework. Maybe it just doesn’t fit.