Susskind says Universe is not Real

Another respected physicist has gone off the deep end. In a new video:

Why the Universe Is Not Real | Leonard Susskind

At first glance, the idea sounds absurd. The universe feels undeniably real. Galaxies exist. Space stretches outward. Matter occupies locations and evolves over time. How could the universe not be real?

In this video, we explore what physicists actually mean when they challenge the reality of the universe. “Not real” does not mean “does not exist.” It means something far more precise — that the universe we experience may not be fundamental. ...

0:00 The universe is not real. I know how that sounds. It sounds like philosophical nonsense, like something a stoned undergraduate would say at 3:00 in the morning. But I'm serious. After spending decades studying quantum mechanics, black holes, and the foundations of reality, I've come to a conclusion that would have shocked my younger self. The universe, as we experience it, is not fundamentally real.

He gives several arguments: (1) Schroedinger Cat is dead and alive simultaneously; (2) We only see one world of many-worlds theory; (3) Physical states are sometimes determined by a boundary condition, so we are a hologram; (4) At the Planck scale, quantum gravity teaches that spacetime breaks down; (5) Observations depend on what observers do.

Let me connect this to black holes again 13:16 because that's where these ideas become most concrete. When you fall into a black hole, you experience crossing the event horizon smoothly. From your perspective, the interior is real. You fall through space toward the singularity. But from the perspective of someone outside, you never cross the horizon. You appear to freeze at the horizon. ...

The fundamental 14:03 reality is the quantum state of the black hole,

He ends up concluding that the universe is not real. So what is real? The Tegmark mathematical universe and consciousness.

20:09 Everything you think is real, solid, definite, is actually quantum, abstract, probabilistic at the fundamental level. The classical reality is an illusion your brain constructs from quantum information. The universe is not real in the way you think it is. It's something uh far stranger. ...

Love is an emergent 21:23 phenomenon arising from brain chemistry, from evolutionary psychology, from social structures. Does that make it less real, less valuable? Of course not. ...

The 23:22 universe is not real in the naive sense. And that's one of the most important discoveries in the history of physics. It changes everything about how we understand reality and our place in it. ...

The universe is not real. 24:14 And that's the most profound truth about reality I've ever discovered.

He is a good illustration of how modern physics has gone wrong.

The Golden Age of Phyics was 1860-1935. Then everyone idolized Einstein for his foolish pursuit of unified field theory and rejection of quantum mechanics. Theoretical physicists studied quantum gravity, nonlocal interpretations, strings, holograms, black hole firewalls, many-worlds, landscape, etc., all to no end.

Susskind went through phases supporting all that stuff, and ends up denying reality.

He is now firmly in the existential crisis iceberg. Accepting what he says is the same as saying we live in a simulation, or that reality is a dream.

All his favorite theories -- hologram, many-worlds, Tegmark math universe -- leave no room for free will or scientific inquiry. He denies that it is nihilism, but that is exactly what it is. We are worse than rats in maze.

He goes wrong at the start, with the Schroedinger Cat. The Cat is just a simple example of uncertainty about two possible events. There is no deep math or physics involved. A child can understand that he might not know what is in a box. But it is very strange to make the leap from that to saying that the universe is not real. I do not think that I could convince a 4-year-old of that.

Susskind also has a new video:

Why Objects Don’t Really Exist | Leonard Susskind

Objects feel like the most basic elements of reality. Tables, chairs, planets, particles — the world appears to be built from things. It seems obvious that objects exist. But modern physics tells a very different story.

In this video, we explore why objects may not be fundamental at all. “Don’t exist” does not mean imaginary. It means that objects are not the deepest level at which reality is defined.

He talks about cats, fuzzy objects, ships with boards replaced, entangled particles.

Another video says:

Why Time Is a Byproduct | Leonard Susskind

We usually think of time as one of the most fundamental ingredients of reality. Everything seems to move through time. Causes come before effects. The universe appears to unfold moment by moment along an invisible timeline. But modern theoretical physics suggests a very different picture.

In this video, we explore the unsettling idea that time may not be fundamental at all. Instead of being the engine that drives reality, time may be a byproduct — something that emerges from deeper processes rather than causing them.

And another new video says black holes are not real:

Black holes are usually imagined as objects with a deep, hidden interior — a place where matter falls and disappears forever. This image is deeply ingrained in popular science. But modern theoretical physics suggests something far more surprising: black holes may not have an interior in the way we think.

In this video, we explore why physicists increasingly question the idea of a black hole interior. “No interior” does not mean nothing happens when something falls in. It means that the information describing that object is not stored inside the black hole as an internal structure.

He says he spent years trying to convince Hawking that if you throw a book into a black hole, then the information will eventually bubble out the surface. His main argument that there is no interior is that if the book fell down to the center, then it is hard to see how the info would ever get out.

He can get away with saying anything he wants about a black hole interior, because it is not observable. But he gets totally wacky and says wormholes are the same as quantum entanglement.

I see now that Susskind has just put out a lot of these videos. Have fun listening to erudite nonsense.

On second thought, I think I have been duped by AI slop. These podcasts have Susskind's voice and his his opinions, but they are more forcefully and coherently argued than he does in real life. I think some AI has scanned his lectures and writings, and made them more intelligible.

I semething similar with Roger Penrose. See Quantum Mechanics Is NOT Random. It is a very good summary of Penrose's view on the subject, and rendered in his own voice. Here is another on Gravity Isn't Pulling You Down — The Ground Is Pushing You Up, and one on Einstein Was Right: Past, Present & Future Are An Illusion — Here's The Proof.

These podcasts are the future of education, I am afraid. They are better than the real Susskind and Penrose, and faithful to their opinions and voices. Maybe we will not have live lectures anymore. Someone will give several lectures on a subject, and then an AI will distill, refine, and polish the material into a better lecture.

Getting back to the original topic, Susskind is not real. He is an AI reconstruction.

Has quantum advantage been achieved?

Dominik Hangleiter writes on his blog:

Recently, I gave a couple of perspective talks on quantum advantage, one at the annual retreat of the CIQC and one at a recent KITP programme. I started off by polling the audience on who believed quantum advantage had been achieved. Just this one, simple question.

The audience was mostly experimental and theoretical physicists with a few CS theory folks sprinkled in. I was sure that these audiences would be overwhelmingly convinced of the successful demonstration of quantum advantage. After all, more than half a decade has passed since ...

I could not have been more wrong.

In both talks, less than half of the people in the audience thought that quantum advantage had been achieved.

No, quantum supremacy has not been achieved, if most experts are not convinced. The whole was to do a public demonstration that convinces everyone that quantum computers are possible.

Dr. Bee Revives Nonlocal gravity

Sabine Hossenfelder posts a new video:

0:38 The laws of physics that we have discovered have one thing in common: they are local. This means that objects in two different locations cannot interact with each other. They don’t know anything of each other. ...

A bit like theorists and experimentalists. 0:53 It is only by sending some sort of signal from one object to the other that they can react to each other’s presence. We have no idea why the laws of nature are this way. There’s no particular reason why they should be. It’s just that it corresponds to our experience.

I would say that there are reasons. Locality is the whole basis of scientific reductionism. It allows us to do controlled experiments. Without it, we could never make sense out of the world.

Also, it is all a consequence of the non-euclidean geometry of spacetime.

1:09 Newtonian gravity is not local, this bothered Newton a lot back then. You see if you take Newton’s law of gravity, with the gravitational force proportional to the mass divided by the square of the distance, then if you move the mass, the distance increases and the force changes instantaneously, everywhere. Newton was greatly bothered by this. He called it “action at a distance” and that’s also what Einstein meant by the phrase.

1:39 Einstein’s theory of general relativity, which we use now to describe gravity, doesn’t have this problem. In Einstein’s theory, gravity is described by the curvature of space and time. And that curvature is caused by the mass and energy in spacetime. If you move the mass that causes spacetime to curve, then the curvature changes, but not instantaneously. The change spreads outwards at the speed of light

Actually it was Poincare who figured out that gravity propagates at the speed of light. Einstein did not accept or believe it.

And this nonlocal gravity just seems to do it. 4:18 Better still the idea that gravity isn’t entirely local is something you’d expect to naturally occur in a theory of quantum gravity because we know that quantum physics isn’t local. I really like the idea.

No, this is crazy talk. Quantum physics is just as local as general relativity. In cosmology, you could have a couple of orbits that are correlated, so that knowledge of one tells you something about the other. That's all people mean by quantum nonlocality.

A reader will surely say that no, quantum nonlocality means that a correlation could be quantitatively greater that what a believer in an alternative theory might expect. Yes, that is true, but it does not have a bearing on whether a theory is local or nonlocal.

In another video, she endorses the Einstein block universe.

Maybe this video more than anything explains why I've always been a bad 11:30 fit for academia. Because what really is this? Is it philosophy? Is it physics? It's neither here nor there. Yet for me, questions like this are the reason I studied physics because I want to understand how the universe works.

Academia has no need for her twisted ideas about how the universe works.

Elsewhere she expreses a belief in superdeterminism, but that contradicts some of what she says here. Maybe she has abandoned superdeterminism, but she ought to explain it.

quantum 9:43 physics has an indeterministic unpredictable element which is what happens the moment one makes a measurement. ... There seems to be a difference between the past and the future in quantum mechanics.

Most of the video is an argument that Einstein's relativity requires us to believe in the block universe, where the future is as real as the past. She says different coordinates are allowed, and so the meaning of "now" can be different for different observers.

This is a misunderstanding of relativity. Einstein was a determinist, and did believe in the block universe, but most physicists do not.

Yes, relativity does allow different coordinates, but that does not mean you have to accept another "now", or that the future is determined. Most physicists accept that the CMB radiation defines a universal now, without contradicting relativity.

Even if I accepted that there is no universal "now", and that my future is already in a past coordinate system for some other observer, it would not follow that my future is determined. She defines "now" by coordinate lines, not light cones, so an observer does not even see what is now for him.

Dr. Bee talks about many science topics outside her expertise. These two videos are squarely within her expertise, so I expect better.

Cantor's Diagonal Argument

Cantor's diagonal argument is famous for proving the uncountability of the real numbers. It is not so well known that Cantor's first set theory article proved it differently.

Here is the proof. First of all, we need to assume the completeness of the reals, in some form.

Theorem. If { A_k } is a collection of compact nested subsets of R, the real numbers, then the intersection is nonempty.

Compact means closed and bounded, like the interval [0,1], including the endpoints. Nested means each contains the next. The proof depends on how you have defined R. For example, you could get an intersection point as the least upper bound of the left endpoints.

This is a way of expressing the completeness of the reals. If we used the rationals instead, then we could have nested intervals about √2, and the intersection would not include any rational numbers.

To prove uncountability, suppose we have an enumeration { x_k } of R, and we seek a contradiction. We define a collection { A_k } with x_k not in A_k, and apply the theorem to get a real number in all the sets, and hence not in the enumeration.

Start with [0,1]. Let A₁ be a closed interval subset excluding x₁. Eg, if x₁ = 0.4, then A₁ could be [0,.3] or [.5,1]. Likewise, let A₂ be a subset of A₁ that excludes x₂, and so on, and thus A_k excludes x₁,..., x_k. Applying the theorem gives at least one real in all of the intervals, and hence not part of the enumeration.

This is really a diagonalization argument, and maybe less intuitive, so what's the point?

I like it better. The usual diagonal argument is deceptively simple, as it assumes facts about the reals, such as every decimal expansion converging to a real, and reals having unique decimal expansions, with certain exceptions. This is still a diagonal argument, gets more directly to the heart of the matter, and explicitly uses the completeness of the reals, without the distracting decimal expansions.

Cantor gave a similar diagonal argument to show that the cardinality of a set A is less than the set P(A) of all its subsets.

Suppose not, so that there is some onto function f: A -> P(A). That is, where f(A) = P(A). Then let B = { a in A : a not in f(a) }. If B = f(b) for some b in A, then b is in f(b) if and only if b is not in f(b), a contradiction. Thus the image of f cannot be all of P(A).

This shows that taking all subsets always gives a set of larger cardinality.

Scott Aaronson recommends a video on Cantor's diagonal argument.

Wild Enthusiasm for Quantum Computing

This new interview makes a lot of big claims for quantum computing:

Q-Day — when quantum computers crack all encryption — is coming. Quantum eMotion COO John Young breaks down the pros and cons of what’s to come.

It is all ridiculous. I could not even bear to listen to the whole thing.

I have gotten used to this sort of enthusiasm for AI. But a 100 million people use AI everyday. Quantum computing has very little hope of ever accomplishing anything.

Heisenberg's 1925 Quantum Mechanics Paper

Here is a good new video: How Heisenberg Discovered It. There is more detail here.

It is largely on Heisenberg's famous 1925 Umdeutung paper.

In his article, Heisenberg described a new framework for quantum theory that was based on observable parameters (parameters that could be measured in scientific experiments), such as transition probabilities or frequencies associated with quantum jumps in spectral lines, rather than unobservable parameters, like the position or velocity of electrons in electron orbits. Thus, Heisenberg used two indices for his re-interpretation of position, corresponding to initial and final states of quantum jumps. Heisenberg used his framework to successfully explain the energy levels of a one-dimensional anharmonic oscillator.

Mathematically, Heisenberg used non-commutative operators in his new multiplication rule, i.e. generally A B ≠ B A for quantum quantities A and B. This insight would later become the basis for Heisenberg's uncertainty principle.

This theory beme quantum mechanics, and has been well accepted for a century, described in textbooks, and applied to a trillion dollar industry.

The bizarre thing is that now the leading popularizers of quantum mechanics seem to not understand Heisenberg's first paragraph. The latest offender is the Veritasium channel. I have criticized many others on this blog. What they have in common is that they refuse to accept that quantum mechanics is about observables, and argue that the theory must mathematically represent unobservables.

In their jargon, the unobservables are called hidden variables, and the belief that they should be incorporated into the theory is called realism.

The 2022 Nobel Prize was given for the experimental proof that local hidden variables are impossible. John von Neumann had said so in his 1930 treatise, and the experiments were just confirmation of what the textbooks have said since 1930.

Maybe all the textbooks are wrong, but that is like saying that perpetual motion machines are possible, or that rockets can go faster than light. Anyone making such a claim needs to explain how everyone else has been so wrong for so long.

They do not, of course. They mainly give some silly argument about how QM would be hard to understand if it included the unobservables. Of course that is true, because the whole point of QM since 1925 has been to exclude the unobservables.

When you hear people demand realism, they are essentially demanding commuting hidden variables to represent unobservables. The whole point of QM is to avoid such things.

Another trouble point is the supposed quantum nonlocality. I have come to the conclusion that this is a misunderstanding or rejection of probability, and doesn't even have anything to do with QM. If a theory predicts probabilities, as all physical theories do, then it says there is a chance something happens and something else does not happen. Assume that something involves at least two spatially separated events. As soon as you run an experiment and see that something happens, you immediately learn that something else did not happen, and that conclusion is the supposed nonlocality. You can call this nonlocal, but that is silly as the same thing happens in any theory.

Einstein's Notion of a Principle Theory

Einstein scholar Galina Weinstein

Einstein's distinction between principle theories and constructive theories is methodological rather than metaphysical. Principle theories such as thermodynamics and relativity articulate empirically distilled constraints that delimit admissible microphysical models, while constructive theories remain provisional and revisable....

In late 1919, following the British eclipse expeditions that confirmed the light-bending prediction of general relativity, Albert Einstein agreed to write an explanatory article for The Times of London. Written in German as “Was ist Relativitätstheorie?” and published in English as “Time, Space, and Gravitation” [7, 8], the article was intended not merely as popularization, but as a methodological clarification of the kind of theory relativity is.

In the essay, Einstein contrasts constructive theories (konstruktive Theorien) with principle theories (Prinziptheorien) [7]. This distinction is not merely classificatory but methodological and epistemological in character [22].

Here is that 1919 Einstein paper:

There are several kinds of theory in physics. Most of them are constructive. These attempt to build a picture of complex phenomena out of some relatively simple proposition. The kinetic theory of gases, for instance, attempts to refer to molecular movement the mechanical thermal, and diffusional properties of gases. When we say that we understand a group of natural phenomena, we mean that we have found a constructive theory which embraces them.

But in addition to this most weighty group of theories, there is another group consisting of what I call theories of principle. These employ the analytic, not the synthetic method. ...

The special relativity theory is therefore the application of the following proposition to any natural process: "Every law of nature which holds good with respect to a coordinate system K must also hold good for any other system K' provided that K and K' are in uniform movement of translation."

The second principle on which the special relativity theory rests is that of the constancy of the velocity of light in a vacuum.

No, relativity was not developed as a principle theory. FitzGerald proposed the relativity length contraction in this 1889 paper:

I have read with much interest Messrs. Michelson and Morley's wonderfully delicate experiment attempting to decide the important question as to how far the ether is carried along by the earth. Their result seems opposed to other experiments showing that the ether in the air can be carried along only to an inappreciable extent. I would suggest that almost the only hypothesis that can reconcile this opposition is that the length of material bodies changes, according as they are moving through the ether or across it, by an amount depending on the square of the ratio of their velocity to that of light. We know that electric forces are affected by the motion of the electrified bodies relative to the ether, and it seems a not improbable supposition that the molecular forces are affected by the motion, and that the size of a body alters consequently.

This appears partly inspired by this 1988 Heaviside paper. That is, solid objects are held together by electromagnetic forces, and those fields were known to be warped by motion. Relativity was the constructive consequence.

The relativity principle that laws holding in K must also hold for K' was essentially what Lorentz proved in 1895.

Einstein seemed to disavow all of this when quantum mechanics was discovered. He was happy to avoid the question of how the FitzGerald contraction works on the molecular level, but refused to accept a quantum theory that did not explain the Heisenberg uncertainty on an atomic level.

It is interesting that in 1919 Einstein was still using 1895 terminology, and not saying that the laws of nature must be in covariant equations, or that the laws must be well-defined on a non-Euclidean manifold.

Weinstein posted some other goofy papers recently, including this on Einstein EPR entanglement, and this comparing Heisenberberg-Schroedinger to the P=NP problem. The Heisenberg and Schroeding theories were mathematically equivalent, but she has a whole paper analogizes them to things that are completely different.