NY Times celebrates general relativity centennial

NY Times editor and Einstein biographer Dennis Overbye writes on the general relativity centennial:

This is the general theory of relativity. It’s a standard trope in science writing to say that some theory or experiment transformed our understanding of space and time. General relativity really did. ...

Hardly anybody would be more surprised by all this than Einstein himself. The space-time he conjured turned out to be far more frisky than he had bargained for back in 1907. ...

Gravity was not a force transmitted across space-time like magnetism; it was the geometry of that space-time itself that kept the planets in their orbits and apples falling.

It would take him another eight difficult years to figure out just how this elastic space-time would work, during which he went from Bern to Prague to Zurich and then to a prestigious post in Berlin.

He makes it sound as if Einstein invented space-time geometry in 1907, and spent 8 years figuring out how to interpret gravity as geometry.

Physics books often say this also, but it is wrong. Poincare discovered the spacetime geometry in 1905, and was the first to apply it to gravity. As I wrote last month:

Many people assume that Einstein was a leader in this movement, but he was not. When Minkowski popularized the spacetime geometry in 1908, Einstein rejected it. When Grossmann figured out to geometrize gravity with the Ricci tensor, Einstein wrote papers in 1914 saying that covariance is impossible. When a relativity textbook described the geometrization of gravity, Einstein attacked it as wrongheaded.

Einstein did make some contributions to the theory, he should only be credited for what he did.

I previously criticized Overbye for the way he credited Einstein for special relativity:

But in Einstein's formulation did objects actually shrink? In a way, the message of relativity theory was that physics was not about real objects, rather, it concerned the measurement of real objects. ...

No such declaration of grandeur, of course, intruded on the flat and somewhat brisk tone of the paper. Albert simply presented his argument and in many cases left it to the reader to fill in the gaps and to realize the implications.

A more complete quote is here. That is a nice statement of the message of relativity, but it was Poincare's view, and not Einstein's.

Extraordinary pages in the history of thought

A SciAm blogger writes:

“The treatise itself, therefore, contains only twenty-four pages — the most extraordinary two dozen pages in the whole history of thought!”

This Hungarian postage stamp does not depict János Bolyai. No portraits of him survive. For more information about the "real face of János Bolyai," click the picture to read Tamás Dénes's article on the subject.

“How different with Bolyai János and Lobachévski, who claimed at once, unflinchingly, that their discovery marked an epoch in human thought so momentous as to be unsurpassed by anything recorded in the history of philosophy or of science, demonstrating as had never been proved before the supremacy of pure reason at the very moment of overthrowing what had forever seemed its surest possession, the axioms of geometry.”

— George Bruce Halsted, on János Bolyai’s treatise on non-Euclidean geometry, The Science of Absolute Space.

Bolyai's non-Euclidean geometry was published in 1832.

Another geometry book says:

“The discoverers of noneuclidean geometry fared somewhat like the biblical king Saul. Saul was looking for some donkeys and found a kingdom. The mathematicians wanted merely to pick a hole in old Euclid and show that one of his postulates which he though was not deducible from the others is, in fact, so deducible. In this they failed. But they found a new world, a geometry in which there are infinitely many lines parallel to a given line and passing through a given point; in which the sum of the angles in a triangle is less than two right angles; and which is nevertheless free of contradiction.”

The blog concludes:

These quotes all seem a bit dramatic for geometry, but it’s easy not to know how truly revolutionary the discovery of non-Euclidean geometry was. Halsted’s description of Bolyai’s paper as “the most extraordinary two dozen pages in the whole history of thought” certainly sounds hyperbolic, but can you find 24 other pages that compete with it?

The creation of non-Euclidean geometry by Bolyai, Gauss, and others was indeed a great vindication of geometry and the axiomatic method. It later became central to 20th century physics when Poincare and Minkowski created a theory of relativity based on it.

Carroll's big picture

Physicist Sean M. Carroll has a new book to be released next year, The Big Picture: On the Origins of Life, Meaning, and the Universe Itself:

This is Sean Carroll's most ambitious book yet: how the deep laws of nature connect to our everyday lives. He has taken us From Eternity to Here and to The Particle at the End of the Universe. Now forThe Big Picture. This is a book that will stand on the shelf alongside the great humanist thinkers from Stephen Hawking and Carl Sagan to Daniel Dennett and E.O. Wilson. It is a new synthesis of science and the biggest questions humans ask about life, death, and where we are in the cosmos. 

Readers learn the difference between how the world works at the quantum level, the cosmic level, and the human level; the emergence of causes from underlying laws; and ultimately how human values relate to scientific reality. This tour of, well, everything explains the principles that have guided the scientific revolution from Darwin and Einstein to the origins of life, consciousness, and the universe, but it also shows how an avalanche of discoveries over the past few hundred years has changed the world for us and what we think really matters. As Carroll eloquently demonstrates, our lives are dwarfed by the immensity of the universe and redeemed by our capacity to comprehend it and give it meaning.

Keep in mind that this is a guy who believes in the many-worlds interpretation (MWI) of quantum mechanics, where your every fantasy is really being played out in some parallel universe.

Update: Publication delayed until May 10, 2016.

Philosopher says scientism leads to leftism

A reader sends an example of a philosopher who supposedly has a scientific outlook. In this podcast, Alex Rosenberg trashes Economics as not being a science. He notes that while economists brag about being able to make certain types of predictions, they are usually completely unable to make any quantitative predictions with any reliability.

Rosenberg has a book on The Atheist's Guide to Reality: Enjoying Life without Illusions.

One chapter is titled "Never let your consious be your guide". I am not sure if he misspelled "conscience", or he is making a pun, or what. Either way, he says "science provides clear-cut answers": You have no mind, you have no free will, and you have no capacity for introspection, rational decision, or moral judgment.

In this interview, he proudly declares his devotion to Scientism, even tho some consider it a pejoritive term. His true science is Physics, and he says he believes in bosons and fermions, and nothing more. But he never actually cites any scientific facts or theories to support any of his opinions. He shows no sign of knowing anything about Physics, except that particles are classified into bosons and fermions.

Even saying that everything is made of bosons and fermions is a little misleading. We have spacetime and quantum fields. Even the quantum vacuum is a nontrivial thing, and I would not say it is just made of bosons and fermions.

After nearly an hour of babbling about the merits of philosophical analysis, he gets to another subject that passes his scientific requirements: political leftism. That's right, the whole thing is just a build-up for a bunch of left-wing political opinions.

He denies that there are any natural rights, but strongly argues for a "core morality". This makes no sense to me.

He says he is "pro-choice" (ie, pro-abortion) but denies that people have any choices because his scientism implies a causal determinism that eliminates free will. So why is he in favor of free choice when there is no such thing?

He says that his scientism implies that we should be soft on crime, because it is inhumane to punish people for doing what they were pre-programmed to do. He also says it is wrong to reward people for hard work or successful business, because again, they are just doing what they were programmed to do. He concedes that we might want a market economy, because science shows that it works better, even tho economics is not a science. But people should never be allowed to get rich, because science proves that they will never deserve the riches.

This is all nonsense. It all rests on Laplacian determinism, but there is no scientific proof of that, and the great majority of physicists today reject it. Even if it were true, his reasoning doesn't even make any sense. He is like a Marxist who advocates pseudo-science with great certainty to fellow humanities professors who like the leftist conclusions and are too innumerate to see the fallacies.

A book review says:

Science – i.e. common sense – tells us that atheism is pretty much a certainty. The reason is quite straightforward. The second law of thermodynamics tells us that disorder and homogeneity steadily increase everywhere in the universe. Whatever physics has left to tell us, it almost certainly won’t contradict this fundamental law. But a purposeful agent, arranging things according to a conscious plan, would be transforming disorder to order. And this is never possible according to the second law (strictly speaking, it is possible, but so improbable as to be ruled out). This rules out most conceptions of God straight away. ...

Vividly and painstakingly, Rosenberg undermines our fundamental belief that we consciously direct our actions. He argues that it is impossible that any of the processes occurring in our brain can have representative content. They can’t be about anything at all. ... This means that our actions can’t, however much they seem to, be caused by thoughts about intended results, or indeed thoughts about anything at all. ...

Despite appearances, then, we aren’t capable of ordering the world by conscious design. In fact, our actions are never caused by conscious intentions. ...

Human life as a whole has no meaning, no goal, and no purpose. Neither our individual lives nor human history in general are governed by purposes – not our own, and not anybody else’s. ... Indeed, there is no ‘you’; the self is another one of those convenient fictions we use to roughly indicate blind processes that have no subjective centre.

The same goes for human history. All apparent progress – the spread of democracy or the global progression towards prosperity – are just local equilibria in a blind arms-race driven by blind selection.

This is neither science nor common sense. God could have created the universe in a very low entropy big bang, and intended that life evolve on Earth while entropy increases in the Sun.

Of course our actions are caused by conscious intentions. And human history has made progress.

I would rather stick to the science, but he does not have much science here, if any. What he has is philosophical nuttiness directed towards some sort of politically leftist nihilism.

Where are the bits in the brain?

Information is reducible to bits, right? Zeros and one. Maybe the quantum computer enthusiasts add qubits, and maybe the Bell spooks might say that non-bit information can travel faster than light.

Brain scientist do not buy into this quantum stuff, so I thought that they believe in bits. But apparently not:

Most neuroscientists believe that the brain learns by rewiring itself—by changing the strength of connections between brain cells, or neurons. But experimental results published last year, from a lab at Lund University in Sweden, hint that we need to change our approach. They suggest the brain learns in a way more analogous to that of a computer: It encodes information into molecules inside neurons and reads out that information for use in computational operations. ...

From a computational point of view, directions and distances are just numbers. ...

Neuroscientists have not come to terms with this truth. I have repeatedly asked roomfuls of my colleagues, first, whether they believe that the brain stores information by changing synaptic connections — they all say, yes — and then how the brain might store a number in an altered pattern of synaptic connections. They are stumped, or refuse to answer.

I guess not much is known about how the brain stores information.

The Bell theorem hypotheses

A commenter disputes my contention that Bell's Theorem depends on an assumption of local hidden variables.

This may seem like an obscure technical point, but it helps explain differing views about Bell's Theorem:

Cornell solid-state physicist David Mermin has described the appraisals of the importance of Bell's theorem in the physics community as ranging from "indifference" to "wild extravagance".

There has been a consensus since about 1930 that hidden variable theory is contrary to the core of quantum mechanics. So another experiment confirming Bell's Theorem is just another affirmation of the legitimacy of those Nobel prizes in 1932 and 1933.

That explains the indifference. So the Bell spooks need a better argument to justify their wild extravagance.

Here is one such attempt, from Wikipedia:

Whereas Bell's paper deals only with deterministic hidden variable theories, Bell's theorem was later generalized to stochastic theories[18] as well, and it was also realised[19] that the theorem is not so much about hidden variables, as about the outcomes of measurements that could have been taken instead of the one actually taken. Existence of these variables is called the assumption of realism, or the assumption of counterfactual definiteness.

This is just a sneaky way of defining hidden variables. Quantum mechanics teaches that you cannot precisely measure position and momentum at the same time. If you assume that particles somehow have precise values for those in the absence of a measurement, then you are in the land of anti-QM hidden variables. If there were any merit to this, then much of XX century physics would be wrong.

John Bell himself later tried to fudge his theorem by pretending to be able to deduce hidden variables from other hypotheses:

Already at the time Bell wrote this, there was a tendency for critics to miss the crucial role of the EPR argument here. The conclusion is not just that some special class of local theories (namely, those which explain the measurement outcomes in terms of pre-existing values) are incompatible with the predictions of quantum theory (which is what follows from Bell's inequality theorem alone), but that local theories as such (whether deterministic or not, whether positing hidden variables or not, etc.) are incompatible with the predictions of quantum theory. This confusion has persisted in more recent decades, so perhaps it is worth emphasizing the point by (again) quoting from Bell's pointed footnote from the same 1980 paper quoted just above: "My own first paper on this subject ... starts with a summary of the EPR argument from locality to deterministic hidden variables. But the commentators have almost universally reported that it begins with deterministic hidden variables."

The commentators are correct. The argument does begin with hidden variables.

In my view, the core of the problem here that some physicists and philosophers refuse to buy into the positivist philosophy that comes with quantum mechanics. Quantum mechanics is all about making predictions for observables, but some people, from Einstein to today, insist on trying to give values for hypothetical things that can never be observed.

The comment asks:

Could you tell me what you mean by "deterministic and separable", and in particular could you tell me how your concept of "deterministic and separable" can account for the perfect anti-correlation without hidden variables?

By separable, I mean that if two objects are separated by a space-like 4-vector, then one can have no influence over the other. This is local causality, and says that physical causes act within light cones. It has been one of the main 3 or 4 principles of physics since about 1860. It is the core of relativity theory.

Determinism is a dubious concept. It has no scientific meaning, as there is no experiment to confirm or deny it. It has never been taught in textbooks, and few physicists have believed in it, with Einstein being a notable exception.

If determinism were true, then you could prepare two identical Potassium-40 atoms, wait about a billion years, and watch them both decay at the same time. But it is hopelessly impossible to prepare identical atoms, so this experiment cannot be done.

Some interpretations of quantum mechanics claim to be deterministic and some claim the opposite, and they all claim to be consistent with all the experiments. So this notion of determinism does not seem to tell us anything about quantum mechanics.

As I wrote last year:

If determinism means completely defined by observables or hidden variables obeying local differential equations, then quantum mechanics and chaos theory show it to be impossible.

So I am not pushing determinism. It is an ill-defined and unscientific concept.

If some EPR-like process emits two equal and opposite electrons, then maybe those electrons are physically determined by the emission process. Or maybe they are intrinsically stochastic and have aspects that are not determined until a measurement. Or maybe it is all determined by events pre-dating the emission. I do not think that these distinctions make any mathematical or scientific sense. You can believe in any of these as you please, and positivists like myself will be indifferent.

When the experimenters get together later to compare their results, they make an astounding discovery: Every time the two experimenters happened to measure a pair of entangled electrons along the same direction, they ALWAYS got opposite results (one UP and one DOWN), and whenever they measured in different directions they got the same result (both UP or both DOWN) 3/4 of the time.

What makes this astounding is if you try to model the electron spin by assuming that there is some underlying classical spin to explain all this. That means that there is always a quantitative value for that spin, or some related hidden variable, that defines the reality of the electron. Some people call this "realism", but it is more than that. It is identifying the electron with the outcomes of potential measurements that are never made.

Everything we know about electrons says that this is impossible. You can measure position, and mess up the momentum. You can measure the X-spin, and mess up the Y-spin. And we can only make these measurements by forcing the electron into special traps, thereby making obvious changes to the electron.

Thus, contrary to widespread beliefs, Bell's Theorem and its experimental tests say nothing about locality or determinism or randomness. They only rule out some hidden variable theories that everyone (but Einstein) thought were ruled out in 1930.

I am not saying anything radical or unusual here. This is just textbook quantum mechanics. Those textbooks do not say that Bell proves nonlocality or indeterminism. I don't think so, anyway. That is why so many physicists are indifferent to the subject, and no Nobel prize has been given for this work. It is just 1930s physics with some wrong philosophical conclusions.

Lubos Motl just posted a rant against a BBC documentary:

I have just watched the first of the two episodes of the 2014 BBC Four documentary The Secrets of Quantum Physics. ...

Needless to say, after having said that Einstein's view has been conclusively disproven, Al-Khalili says that he believes in Einstein's view, anyway. Hilarious. Sorry, Mr Al-Khalili, but you just violate the basic rules of logic in the most obvious way. You should really reduce the consumption of drugs.

Before I watched the full episode, and even in 1/2 of it or so, I wanted to believe that it would be a documentary on quantum mechanics that avoids the complete idiocy and pseudoscience. Sadly, my optimism was misplaced. This is another excellent representative of the anti-quantum flapdoodle that is being spread by almost all conceivable outlets of the mass culture.

I haven't watched it, but it sounds like a lot of other popular accounts of quantum mechanics. They get the early history pretty well, and then they tell how Einstein and Bell did not believe it, and tried to prove QM wrong. Then the experiments proved QM right and Einstein and Bell wrong. But then then end up with some crazy conclusions that do not make any sense.

Update: There is some discussion in the comments below about whether Bell assumes hidden variables, and when he leaves Bohr's positivistic view of quantum mechanics as a possibility. You can see for yourself in Bell's 1981 socks paper, which is here, here, and here. He uses the letter lambda for the hidden variables.

Teen wins prize for relativity video

USA Today reports:

Meet Ryan Chester, 18, whose quirky video explaining Albert Einstein’s mind-bending Special Theory of Relativity won the inaugural Breakthrough Junior Challenge Sunday. The prize nets the North Royalton (Ohio) High School senior $250,000 toward college; $50,000 for Rick Nestoff, the physics teacher that inspired him; and $100,000 for a new school science lab.

Parents, take note: That's not too shabby a haul in exchange for a zippy 7-minute clip.

It is a slick video, and it follows closely a common textbook explanation in terms of Einstein's postulates (ie, Poincare's relativity principle and Lorentz's constancy of the speed of light), the Michelson-Morley experiment, and spacetime without an aether.