Should we take Boltzmann Brains seriously? If not, why not?

I recently read an academic paper on Boltzmann Brains (3 Dec. 2025), jointly authored by David Wolpert, Carlo Rovelli and Jordan Schamhorst. Under their names are listed 5 institutions, in the following order:
 
Sante Fe Institute, Sante Fe, USA.
Centre de Physique Theorique de Luminy, Marseille, France.
Department of Philosophy, The Rotman Institute of Philosophy, London, Ontario, Canada.
Perimeter Institute, Ontario, Canada.
Physics Deparment, University of California, Santa Cruz, USA.
 
For those who don’t know, Boltzmann Brains (BBs) are a hypothetical, similar to the brain-in-a-vat idea I referenced in the addendum to my last post. But this idea has more relevance to that post than just that analogy, which will become obvious as I proceed.
 
The first sentence of their Abstract provides as good a definition of a BB as you’re likely to find.
 
Are your perceptions, memories and observations merely a statistical fluctuation arising from the thermal equilibrium of the universe, bearing no correlation to the actual past state of the universe? Arguments are given in the literature for and against this “Boltzmann brain” hypothesis.
 
There is an argument that if the universe exists for long enough in a heat death, then the probability of a fully functioning brain just coming into existence as a quantum fluctuation will become greater than zero (even one). If this hypothesis is true, then you don’t know if you’re a BB or not.
 
The paper discusses previous arguments against BBs, which the authors find circular, and propose what they call a more rigorous approach. They use the language of logic and probabilities to support their arguments and discuss previous ones. I will do my best to avoid that, because I believe one can apply philosophical arguments to dispute the existence of BBs.
 
Like the brain-in-a-vat hypothesis, I don’t believe anyone actually thinks they’re a BB, yet we’re told that we need to take them seriously. The authors devote an entire section of their paper to How and Why Intuition Leads Us Astray, basically arguing that we can no longer trust ‘common sense’ in the wake of quantum physics and relativity, both of which defied longstanding tenets of common sense. However, I think there are important differences; not least, the matter of evidence.
 
I’ve written previously that science is all about explanations. Newton’s theory of universal gravitation, not only explained why objects fall to Earth, but why the Earth orbits the Sun. Darwin and Wallace’s theory of evolution explained the diversity of species and why species geographically isolated evolved differently from each other. It’s very important to appreciate that neither of these theories explained everything in their respective fields, and consequential discoveries and hypotheses have expanded them without completely overturning them.
 
My biggest bone of contention with the BB hypothesis is that it doesn’t explain anything that’s not already explained more effectively by existing theories, and certainly adds nothing new to our knowledge of the Universe. In fact, it’s arguably a hypothesis to explain everything away.
 
In the case of relativity theory, it explained events hitherto unexplained, like the precession of the perihelion of Mercury’s orbit, and predicted new phenomena like clocks slowing down at relativistic speeds. Quantum mechanics (QM) explained previously unexplained phenomena like black body radiation and the photo-electric effect, while predicting new phenomena like anti-particles and entanglement, both confirmed by experiment, even if the experiments were performed over half a century later. There is no experiment I’m aware of that can confirm the existence (or non-existence) of Boltzmann Brains, and not surprisingly, the authors don’t entertain that possibility.
 
One of the arguments you rarely hear these days, but I’ve heard expressed by Carl Sagan, among others, is that there is a unity within science across disciplines. For example, our theories of cosmology don’t contradict our theories on biological evolution, though they could. Some might argue that relativity and QM don’t play nice (euphemistically speaking), but that demonstrates a gap in our knowledge rather than a reason to scrap either one of them.
 
The BB hypothesis, by comparison, infers that all these interactions between evolution, genetics, cosmology and quantum phenomena are all figments of our minds, because there can be no history. Take the literal everyday experience of night and day having a causal relationship arising from the rotation of the planet we all live on. How does the BB hypothesis explain that? To borrow a term coined by Sabine Hossenfelder, I would call it ‘ascientific’. Basically, it’s a thought experiment with mathematical underpinnings.
 
I won’t elaborate on the authors’ arguments in detail, partly because they’re very esoteric. Nevertheless, I’ll cherry-pick in an attempt to convey the gist of them. One of their points is that if entropy can be time symmetrical, meaning explicitly that entropy can increase into the past as well as the future, then BBs are likely because they are complex by definition, therefore require very low entropy. The very last part of that sentence is mine, not theirs, but I assume that’s the conclusion based on time-symmetrical entropy, which is their argument supporting the BB hypothesis.
 
Then, if I understand them correctly, the only reason we believe entropy is time asymmetrical (only increases into the future) is because of the second law of thermodynamics. I don’t think anyone would argue that entropy and the second law are not related, but their relationship to the asymmetry of time is not necessarily causal. In other words, I think there are other factors to time irreversibility, which I discuss below.
 
My understanding of entropy is that it’s fundamentally probabilistic, and this is reinforced by Erwin Schrodinger and Richard Feynman, both of whom used a pack of cards as their analogy for entropy. The more you shuffle a pack of cards the less likely you are to return it to its original state. That’s a simplification, but I think it’s a good analogy for anyone who is not a physicist (which includes me, btw). The thing is that the equation for entropy effectively looks at all the states that a system can have, and it will always increase in time (in a closed system). In an open system with an external energy source, it can be reversed or you can have increased ‘complexity’, which is what you have with the Earth and its relationship with the Sun as an external energy source (refer Paul Davies, The Cosmic Blueprint, 1987).
 
The authors spend a lot of time on the second law of thermodynamics, and in particular, they claim it’s essential to the role of memory. Specifically, they argue that we wouldn’t have memories without the second law. As discussed below, they basically argue that only the second law gives us an asymmetry in time, and without that asymmetry, memories of a past can’t exist.
 
In fact, they specifically point out that our belief in the accuracy of our memories is premised on the assumption that our knowledge of the past is more accurate and reliable than our knowledge of the future because we intrinsically accept the asymmetry of time. They then make the point that we make this assumption with no knowledge of thermodynamics, with the inference that this knowledge should give us pause regarding the validity of memories.
 
They then give analogies of the craters on the moon and footsteps in the sand, as providing physical ‘memories’ of previous events, similar to memories in our physical brains. Below is their own conclusion to this argument.
 
In fact, these examples do have one striking feature in common: all of them seem to rely on the second law of thermodynamics. The temporal asymmetry of these memory systems, and by extension of our human brains, seems to reflect nothing more than the simple fact that entropy increases in time. Indeed, the precise reason we are so very sure about some of our memories seems to reflect the ironclad nature of the second law.


In other words, the reason we seem to have so much confidence in our memory ultimately resides in the fact that those memories rely on the second law.
 
I confess I have problems with this argument. For a start, I’m not convinced that entropy and the second law is what gives us asymmetry in time. I think the collapse of the wavefunction in QM is what provides the asymmetry in time. To quote Paul Davies (out of context):
 
The very act of measurement breaks the time symmetry of quantum mechanics in a process sometimes described as the collapse of the wave function…. the rewind button is destroyed as soon as that measurement is made.
 
I agree that overall entropy increases with time for the entire universe, but that doesn’t mean it’s the cause of the asymmetry in time we all observe and is often recorded, irrespective of individual memories. And I haven’t mentioned how chaos theory seems to break the symmetry of time, given that a chaotic event can’t be repeated, with a coin toss being the most obvious example, and weather being the most commonly observed. Chaos ensures that the future is ultimately indeterminable, even when the past is recorded, so you have an asymmetry in time without the second law.
 
Right at the end, the authors have a section titled, Discussion, which is really a summation of their arguments. Basically, they argue that the BB hypothesis without the second law is just as valid as the PH (past hypothesis), meaning there is a past. In fact, they argue that before the cosmological discoveries of the 20th Century (which indicate a history for the entire universe), the BB hypothesis could not be dismissed without assuming the second law. To quote:
 
…the only reason we have for assigning more credence to the PH or even to the second law than we assign to the BB hypothesis is the credence we assign to our cosmological observations concerning the big bang. This means in turn that before the early 20th century, when we first made those cosmological observations, we should have treated the BB hypothesis as just as probable as the second law. (My emphasis)
 
They argue that the common acceptance of PH over BB ‘currently in vogue’ (their words) is ‘naïve’. I think there is another way of looking at it, which, no doubt, they would consider even more naïve. What if time asymmetry is a fundamental feature of the Universe and the second law and entropy are a logical consequence arising from that asymmetry in the form of increasing probabilities over time, like the shuffling of a pack of cards? If that was the case, then surely the BB hypothesis would be dead in the water.
 
If the second law and increasing entropy are a consequence of the asymmetry in time, and not its cause, then memory is independent of the second law, because it’s a logical consequence of past events being more reliably known (recorded) than future (chaotic) events. I’m sure the authors would find this naïve as well, yet the entire universe seems to obey this law: the past is observable and the future is not.
 
To quote Freeman Dyson:
 
“We do not need a human observer to make quantum mechanics work. All we need is a point of reference, to separate past from future, to separate what has happened from what may happen, to separate facts from probabilities.”
 
The ‘point of reference’ being the intersection of the past and future light cones for every observer in the Universe, whether it’s a BB or not. However, a BB is the subject of a thought experiment, whereas you and I create the actual thought. Isn’t that ironic? Actually, it's self-referential, if one was a BB.

 
I can’t help but think of my last post and what Curt Jaimungal would have made of my arguments. Based on what he’s previously argued, I expect Curt would contend that I only ‘believe’ I’m not a BB, and that I don’t actually ‘know’. But here’s the thing: if I’m wrong about NOT being a BB, then I must be wrong about everything else I claim to ‘know’.
 

Addendum: I confess I’ve been troubled by the notion of memory being linked to the second law or entropy. Certainly, I can see how the deterioration of memories over time, which we all experience, can be related to increasing entropy, but the authors don’t explicitly say that. I’m sure the creation of memories requires energy, so there is a thermodynamic reaction in as much as you use sugar for any brain process, of which memories are probably the most common. But from the brain’s perspective, the energy is an external source, which ultimately comes from food we ingest.

There is another point, which is that, without memory, you wouldn’t know you’re conscious. A point I’ve made before. Now here’s the thing: if you are a BB, then you’re conscious, which means you need to have memory, which axiomatically defeats the authors’ argument.
 

Could time-travel subvert Fermi’s paradox?

It’s a little tongue-in-cheek, but I don’t find it totally out-of-the-question either. This post is a confluence of a few things, only two of which are mentioned in the title.

The best exposition of Fermi’s paradox I’ve come across, is by Prof Brian Cox. In fact, he provides a very good succinct definition in the first 2m of his video.

 

Notwithstanding the fact that there has been billions of years on billions of worlds for civilisations to arise, we see no evidence of any of them in the Galaxy at all. So the paradox is, Why?

 

He then uses the remaining 20+ minutes of the video, providing expositions on various reasons why this is the case. Firstly, he gives a history lesson, explaining how life on Earth took close to 4 billion years to evolve to its present state. He doesn’t mention that humans (homo sapiens) only arose in the last 3-400,000 years of that, so the last 0.01% or thereabouts, and it’s only in the last century of that 300k+ years that we developed very rudimentary extra-terrestrial space exploration capabilities (my point, not his). So a blink-of-an-eye in the context of our evolutionary history.

 

He goes on to give various scenarios why the Fermi paradox exists but the one most pertinent to this post (around 7m) is that the distance between worlds that could have the same properties as our solar system, in being able to create a stable environment over tens of billions of years for life to evolve, are at least thousands of lightyears away (in our galaxy), and therefore beyond the ability to travel here in the timeframe that such distances dictate. He points out that even the time required for receiving radio transmissions are commensurate with the distance to be traversed. Which is why searching for ‘artificial’ signals is the most efficient method to look for extra-terrestrial civilisations.

 

One of his best arguments involves Von Neumann machines or ‘replicators’, which are self-replicating robots, which could colonise a galaxy within 100s of millions of years (his estimate). He contends that the fact we’ve never seen any, is the best indicator we have that a spacefaring civilisation doesn’t exist in our galaxy.

 

I won’t elaborate on any of the other scenarios Cox expounds upon, but I recommend watching the full 23m, because it’s very stimulating and informative. He also talks about the ‘Great Filter’ (~10m), which is a scary yet totally plausible scenario, although not relevant to this post. Basically, he says that civilisations like us, who can create the technology for space-travel, also have the technology to destroy ourselves, and may lack the wisdom to do one over the other. In his own words, we’re brought undone by our ‘stupidity’.

 

His best argument he left to last, which I’ve reported on before, but based on Nick Lane’s excellent book, Life Ascending; The Ten Great Inventions of Evolution. Basically, Cox argues there was 4B years of life before complex life arose, and it’s such a rare possibility that maybe it’s never happened anywhere else. Note: this doesn’t rule out simple life being prolific throughout the galaxy. He cites John Barrow's and Frank Kipler’s book, The Anthropic Principle, which he explains, he grew up with, as supporting that particular view. I read that book and reference it here.

 

That took longer than I intended, so now I will address the other part of my question, which is time-travel. Another physicist, Jim Al-Khalili, who wrote an excellent book called Paradox (which I’ve read) has a video titled provocatively, Could I Travel Back in Time? where he explores various time-travel scenarios.

 

Naturally, he starts with the well known grandfather paradox, whereby you travel back in time to kill your grandfather before he met your grandmother, thus breaking the causal chain for your own existence. This idea was exploited in the original Terminator movie. In fact, it’s hard to talk about time-travel without referencing science fiction examples.

 

He then uses the scenario of having found instructions to build a time machine, actually builds it, which takes him 10 years, then travels back 10 years in time to drop the instructions on his desk. Al-Khalili points out a couple of issues: it defeats free will because if the scientist ‘chooses’ not to travel back in time, it can’t happen at all; and the instructions are never actually created in the first place, so causality is overturned. He also mentions the problem of having 2 versions of the scientist existing at the same time, therefore breaking the first law of thermodynamics: conservation of energy.

 

He then talks about how travelling into the future is physically possible according to Einstein’s theories of relativity, either by travelling close to the speed of light, as per the famous twin paradox thought experiment, or spending time in a strong gravitational field, as per the movie, Interstellar. A version of the last one, I’ve used in my own science fiction.

 

Al-Khalili draws a spacetime diagram showing the future and past light cones, which features strongly in my way of viewing this. But without getting ahead of myself, he points out that, according to GR (Einstein’s general theory of relativity), if you could curve spacetime strongly enough you could create a time-loop. In fact, this would be a feature of a rotating universe, as pointed out by Einstein’s friend, Kurt Godel, as well as a possibility for a rapidly spinning black hole. There is good reason to believe we don’t live in a rotating universe, but rotating black holes, one assumes, are quite common. Could one get stuck in a time-loop at the event horizon of a spinning black hole? I don’t know.

 

Al-Khalili cites Russian astrophysicist, Igor Novikov, who proposed his own rule, regarding CTCs (Closed-Timelike-Curves): ‘Only “logically self-consistent” solutions are allowed’.

 

Al-Khalili then introduces us to Dr Fabio Costa, who has published a paper where he talks about taking time-slices, where cause-and-effects create boundary conditions, which neither he nor Al-Khalili explain in detail. But Costa concludes by saying, “Nature is smart enough to prevent such paradoxes” (referring to the grandfather paradox, specifically). My takeaway, which admittedly is rather simplistic, even superficial, is that cause-and-effect is such a fundamental principle in physics, that any scenario that sidesteps it, needs to be treated with extreme caution. I should point out that there are scientists and philosophers (like Donald Hoffman) who think that causality, as a principle, is past its use-by date.

 

As Al-Khalili sums up, Fabio Costa argues that “time paradoxes disappear, not because they’re logically inconsistent, but because they’re physically not allowed.”

 

Al-Khalili also refers to the Many Worlds Interpretation (MWI) of quantum mechanics, as providing another loophole, for want of a better expression, to allow time-travel without creating paradoxes. In fact, this is the scenario invoked in the Back to the Future movie franchise. When Marty McFly goes back to the past and intervenes, he subsequently finds himself in a different universe when he returns to the present. Al-Khalili explains how this resolves the grandfather paradox very neatly (similar to the Marty McFly scenario), but like me, he has issues with MWI as a reality.

 

Lastly, Al-Khalili talks to Dr Lorenzo Gavassino at the Department of Mathematics, Vanderbilt University, Nashville, Tennessee, who took a serious look at the Groundhog Day scenario, but proposes that the individual was in a closed box that underwent a time loop. Specifically, he looked at how this is impacted by the 2^nd Law of Thermodynamics or entropy, because when the individual went back in time their entropy would decrease and their memories would be erased. Again, I might be simplifying it for the sake of explication, but it’s what I expect a time loop would create. The way Gavassino describes it, including his literal handwaving, the time loop has 2 nodes, where at one node the entropy is at its lowest and at the other node, entropy is highest. And effectively, the individual oscillates between these two extremes.

 

Right at the end, Al-Khalili makes the point that I’ve heard before, which is that if someone did invent a time machine, it could never go back to earlier than the time it was invented, which is why we’ve never seen one.

 

Again, I spent much longer on this than I intended but I’m now going to reference yet another video that talks about the edge of time for the entire universe. In essence, I’m going to discuss a video by Curt Jaimungal who discusses an aspect of Einstein’s GR that I’d never heard about before. Curt often discusses very esoteric topics, but I’m confident he knows what he’s talking about, because I’ve seen him hold his own with such luminaries as Stephen Wolfram, Gregory Chaitin, Sir Roger Penrose and Sabine Hossenfelder. In fact, I watched a 2hr video conversation he had with her after he sent me a link, and they were very chatty and friendly.

 

I had to watch this more than once to get my head around it, and I’ll rely heavily on quotes to get my points across. As a side-issue, he addresses a conundrum I’ve raised many times before, which is that the Universe has an edge in time, but not space (as best we can tell), yet relativity theory tells us that there is no universal now. I’ll get to that, but first I’ll address what the video is primarily about.

 

What the video is about, contrary to what everyone seems to believe, including Einstein himself, based on what I know, is that his GR equations don’t provide for a deterministic universe at the very limit or edge of the Universe in time. In fact, Curt contends that it is even less deterministic than quantum mechanics with an infinity of possibilities. At one point, he quips, “God does not even play dice, He just shrugs.”

 

But what I want to focus on, is what Curt calls a ‘Cauchy surface,’ which, if I understand him correctly, is the hypersurface that we are all familiar with in the spacetime diagram that Al-Khalili referred to in his video, which also shows the past and future light cones for any observer at time, t.

Significantly, Curt distinguishes between local determinism and global determinism, because he argues that GR allows for one and not the other, and this is also relevant to determining what ‘now’ means. Significantly, global determinism "determines the future of the entire universe", whereas local determinism refers to "what happens in the immediate future of that region [of space]".

 

Curt defines a ‘Cauchy surface’ as “a spacelike slice, that every causal curve hits exactly once.” He emphasises this with beats of his hand for every single word. An obvious consequence of this is that there can be no time loops.

 

He then asks the obvious question: can you extrapolate local determinism to global determinism? His answer is very informative in that he contends that in flat spacetime this is ‘trivial’ because you can, but not in curved spacetime, which is what GR describes. I think this is also relevant in attempting to understand what a universal now means.

 

In fact, Curt says, specifically, “There are solutions to the field equations of Einstein [in GR] where you literally can’t define a moment of time across the entire universe.” He then emphasises the point, by saying: “In general relativity, there may not be a way to slice spacetime in all of space at time t.” Note, this is a consequence of spacetime curvature and not SR (special theory of relativity) as most arguments claim.

 

And there’s a term for this, which is ‘global hyperbolicity’, and that’s where he introduces his definition of a Cauchy surface which I referenced earlier. So the spacelike slice where every ‘causal curve’ only crosses once, applies to the entire universe.

 

Then, in an apparent contradiction to what he told us before, he says “the Cauchy surface is like a snapshot of the universe at one time.” He then emphasises again that “every world line [for a particle] and every light ray; they all cross the surface exactly once.” He then says, “This is what even allows you to say, the state of the Universe at time t.” And I think this is the closest you will get to the idea of a universal now. But there is a caveat, which is that “not all solutions to Einstein’s equations are globally hyperbolic.”

 

He then provides examples which mostly include black holes, including rotating black holes, which I mentioned in reference to Al-Khalili’s video. He also mentions Godel’s rotating universe, which I think we can confidently say, we don’t inhabit.

 

Curt has an understanding of this topic that makes me realise how little I really know. What I do know is that clocks measure time at different rates depending on gravity, so if you happened to live near a black hole, you would measure the age of the Universe as younger than someone on Earth, so you would axiomatically get a different t.

 

What Curt doesn’t describe is the possibility that there is a wavefunction for the entire universe, which some scientists believe (like Sean Carroll, for example), and, if it describes the future, as Freeman Dyson believed, then maybe entanglement provides an edge in time for the entire universe. But I’m speculating way beyond the limits of my knowledge.

 

This post has already become too long with detours down various rabbit holes, but there is one more video I want to reference, which has specific relevance to the title.

 

I grew up in a small rural town in Australia, and I’m old enough to remember when TV arrived, though we didn’t own a set until I was 16. The saving grace for me were books, including both the primary school and high school libraries, which I devoured. So it was around 16 years of age that I read a book called The Truth About Flying Saucers by Aime Michel, first published in 1956 (I looked it up), and I admit to being profoundly influenced by it. (I’m not sure you’d find a book on flying saucers in a modern high school in Australia.) It so happened that I had a science teacher who was also interested in UFOs – he was a very good science teacher, by the way, and I’m not the only one who would say that.

 

I’ve since become more sceptical about the whole UFO scene, as I’ve developed what I believe is a healthy scepticism towards conspiracy theories of any ilk. So it’s in that context that I reference an episode of Australian Story on ABC TV, where a group of people from a small town in Australia recollect a particular ‘incident’ from their childhood, involving phenomena that couldn’t be explained at the time, or even now.

 

When I watched this and listened to their testimony, I thought that one explanation, which is even more out-there than the possibility of visitors from outer space, is the possibility that some ultra-advanced technological species has learned how to travel through time from the future. Perhaps only a sci-fi writer would even consider that.

 

But there is another possibility, which I thought of when I watched Brian Cox’s video. If you look at the spacetime diagram depicting past and future light cones, it’s obvious that most of the events in the so-called ‘observable’ universe are ‘unobservable.’ It’s possible, therefore, that there are civilisations billions of light years away, who have developed technologies that exceed ours, which we can’t possibly know about using radio waves, Von Neumann machines or whatever. Unless, that is, they’ve developed the technology to travel through time as well as space.

 

The thing is that if someone (or some object) was able to visit us from outside our past or future light cones, it wouldn’t create a causal loop, unlike all the examples that Al-Khalili provided in his video (except MWI).

 

My conjecture, if I can call it that, which is admittedly more sci-fi than science reality, is: What if a technologically advanced enough extra-terrestrial species developed the ability to ride the hyperplane on the Cauchy surface, while avoiding black holes, and was able to visit our world line? As Brian Cox said at the end of his video, a scientist has to be able to admit they’re wrong, but it would require a visitor in a flying saucer to convince him.

 

Footnote: The last video I referenced, Australian Story, is very good reporting, and I recommend you watch it so you can make your own judgement.

Should you believe me?

Note how prefacing the question with ‘why’ would change its focus if not its intent. I’ll return to this point at the end. I was originally going to write a post on time travel and UFOs, but I got sidetracked in my 'research'. In particular, I watched a talk given by famous sceptic, Michael Shermer (executive director of The Skeptics Society) and I remember reading his column in Scientific American in the 70s or 80s when I was a regular reader. He’s only slightly younger than me.

 

He gives a number of challenges in his talk, which are insightful in themselves, and I would gladly take them up. Basically, he’s making the point that when you challenge someone to explain why they believe something, they mostly can’t. He gives the examples of climate change and evolution, which he says are positions based on political beliefs rather than whether or not they understand the science behind them. I fall into this category, even though I’ve read books and accounts on these topics that most people wouldn’t bother, despite holding very passionate views on them.

 

Regarding evolutionary theory, I’d recommend Nick Lane’s excellent book, Life Ascending; The Ten Great Inventions of Evolution, which I’ve written about before. But I have another argument, which I’ve also presented before. Since Darwin and Wallace independently proposed their theories of evolution by natural selection over 160 years ago (1859 to be precise), we’ve made extraordinary discoveries that they could never have dreamed about, specifically in palaeontology and genetics. But here’s the thing: all the evidence discovered in the interim is not neutral; what has proven them right could just as readily have proven them wrong.

 

Regarding anthropomorphic climate change, I know of the role of greenhouse gases like carbon dioxide (CO2) and methane, without knowing the details, and I know that ultimately it’s caused by the difference in heat that can escape our atmosphere and the heat that’s trapped, which can’t be measured directly. However, NASA has data that is publicly available on their website, which combines historical ice-core data with atmospheric data collected at Mauna Loa in Hawaii, and they show how the 2 sources of data are complementary and seamlessly connected.

 

But I have a subsidiary argument, which is that we need to trust the expertise of people who work in climatology, because the rest of us don’t have it. I learned this from spending over 4 decades in engineering, where I constantly relied on expertise by people in various fields from structural and civil engineering to architecture to mechanical and electrical engineering to process engineering to software design and automation. The problem is, with the internet, you can always find an ‘expert’ to provide the evidence that supports your view, which was very prominently exhibited during the not-so-recent COVID pandemic.

 

But, in the case of climate change, nearly all the arguments I’ve come across (that question it) are that it’s a hoax and/or a global conspiracy to keep climatologists in a job. I admit I don’t take those arguments seriously. However, there is someone I know who was a geologist and had spent a very successful career in mining, who put up a technical argument based on the tonnes of CO2 in the atmosphere and how, as a percentage, it contradicted the official reporting, including that provided by NASA. NASA’s data is in ppm (parts per million), and I pointed out that to convert the weight into ppm you had to allow for the molecular weight of CO2, which brings it back in line with the reported results. He knew I was right and he didn't respond. But as Shermer would have pointed out, he was on the Right of politics and I’m on the Left, which axiomatically creates the divide. I’ve long argued that climate change should never have been politicised. But having said that, you’ll find people on the other side of the argument who will say exactly the same thing.

 

Shermer added a couple of other challenges to demonstrate how much we don’t know or take for granted. He asked, ‘Can you explain how a zipper works?’ No, but I can draw a diagram. Engineers often draw a picture when explaining something. He also asked, ‘Can you draw a bicycle?’ and explained how many people get it wrong. Well, actually, I can. I stopped the video to prove it to myself, though I had to raise the handlebars when I finished it. Mind you, I started drawing before I could write.

 

However, Shermer made me question myself, which is why I’m writing this post. You see I write about topics where I’m not an expert, specifically physics and cosmology. I’m not even a proper philosopher – I don’t even have a degree let alone a PhD. My only defence is that I’m well read and pay attention to people who know a lot more than me, even if I disagree with them. And what I’ve found from watching panel discussions on YouTube is that even experts can’t agree.

 

To give an example, I watched a panel discussion between 2 prominent philosophers of science and a theoretical physicist: Tim Maudlin, Hilary Lawson and Sabine Hossenfelder respectively; on whether there are particles or fields. Tim Maudlin appeared to be the odd one out, yet I found I was more in agreement with him, which might just be a reflection of my own ignorance. Basically, he argued that the ‘field’ in quantum mechanics is the wavefunction of the particle which doesn’t even exist in spacetime (it exists in Hilbert space with potentially infinite dimensions) and can’t be measured. It’s possible that Lawson and Hossenfelder were talking about something different – I don’t know enough to comment – but Hossenfelder said you can have different mathematical models that describe the same phenomenon. Maudlin quoted John Bell as saying we effectively don’t have a particle until it creates a spot on a screen or a photographic emulsion. Which is why I think it exists in the past and the wavefunction exists in the future, compatible with Freeman Dyson’s viewpoint.

 

Speaking of Bell, I watched another video with Neil deGrasse Tyson talking to Jana Levin about entanglement which is one of the best discussions I’ve seen on the topic. The point that I think needs to be emphasised is that entanglement introduces instantaneity, which to me, only makes sense if there is a universal 'now'. Tyson focused the discussion on the ramifications for cryptology, where they both agreed that it can’t be used to send a message faster-than-light, though I do it in my science fiction (I readily acknowledge I break the known laws of physics in my sci-fi).

 

I think there is an inherent contradiction or conundrum in physics and cosmology that the Universe has an edge in time but not space, whereas relativity theory tells us there is only spacetime (they are not separate) and ‘now’ is a purely subjective experience – there is no universal, objective now. This has led to physicists arguing that our experience of time ‘flowing’ is an illusion. Paul Davies believes that this experience will ultimately be 'explained by neuroscience, not physics'. Sabine Hossenfelder argues that there is no ‘now’ – it’s an illusion. Everyone knows that I greatly admire both of these scientists, both of whom know a lot more than me, yet I also think that postulating something that’s so outside our everyday experience, requires better explanations than we currently have. To me, it’s a sign that there is something wrong with our current theories rather than a sign that we all suffer from the same illusion that there is a past, present and future.

 

Getting back to Shermer and the role of expertise (though he doesn’t mention it, but I do): what I’ve found is that if you watch a discussion on a topic like evolution or climate change, especially when it’s combative, and you have someone present who is more knowledgeable and more experienced, they will invariably win the argument. And to extend that to my position, I imagine that if I was to have a discussion with Sabine, she would win hands down, and I would have to defer to her greater expertise, while not necessarily agreeing with her.

 

I once wrote a post where I critiqued her position on determinism and free will. It so happened I referenced this post to someone I met online, and to my surprise they said it was ‘very balanced’. I didn’t think it was balanced at all, given my prejudices, but I took it as a compliment.

 

So, addressing the question at the head of this post, the answer is, No. You shouldn’t simply believe what I say or argue; instead, you should do your own research and draw your own conclusions.