Denmark ignored Galileo

There is a widespread my that Galileo invented the telescope, discovered heliocentrism, and was suppressed by a Pope that would not tolerate new ideas.

The respected physics historia Helge Kragh writes: Galileo in early modern Denmark, 1600-1650

The scientific revolution in the first half of the seventeenth century, pioneered by figures such as Harvey, Galileo, Gassendi, Kepler and Descartes, was disseminated to the northernmost countries in Europe with considerable delay. In this essay I examine how and when Galileo's new ideas in physics and astronomy became known in Denmark, and I compare the reception with the one in Sweden. It turns out that Galileo was almost exclusively known for his sensational use of the telescope to unravel the secrets of the heavens, meaning that he was predominantly seen as an astronomical innovator and advocate of the Copernican world system. Danish astronomy at the time was however based on Tycho Brahe's view of the universe and therefore hostile to Copernican and, by implication, Galilean cosmology. Although Galileo's telescope attracted much attention, it took about thirty years until a Danish astronomer actually used the instrument for observations. By the 1640s Galileo was generally admired for his astronomical discoveries, but no one in Denmark drew the consequence that the dogma of the central Earth, a fundamental feature of the Tychonian world picture, was therefore incorrect.

This is not surprising. The Dane Tycho invented the instruments that made the best astronomical observations in the world, and that data was used for the best models. Galileo had nothing to compete with that.

Galileo said Mathematics is the language in which God has written the universe, but his telescopic observations and heliocentric arguments were not very mathematical.

Kragh concludes:

Whereas Galileo was well known and highly reputed in the first two decades of the seventeenth century, it took longer before he was discovered by astronomers and natural philosophers in the Nordic countries. Tycho Brahe was aware of him at an early date, but he was an exception. The first time Galileo was mentioned in print by a Danish scholar was in 1617, and five years later he appeared in a Swedish publication. Yet, still around 1640 there were only few references to his scientific work. What eventually attracted attention to the innovative Italian were almost exclusively his astronomical discoveries made by means of the amazing telescope. His advocacy of the Copernican world system was noted, but without making any impact. In the first half of the century there still were no Copernicans in either Denmark or Sweden. Astronomers were either Tychonians or supporters of the Ptolemaic theory.

Galileo’s international fame undoubtedly rested on his telescopic discoveries, but of course he also did pioneering work in mechanics and other branches of natural philosophy. First of all, he introduced the experimental method. There seems to be no mention in the Danish scholarly literature of the physical rather than astronomical Galileo. One looks in vain for awareness of or comments on his theory of the pendulum, his laws of freely falling bodies or his ideas about inertial motion; nor is his views on atomism, the void and the nature of heat to be found in the learned literature. These parts of Galileo’s work were foreign to Danish natural philosophers who predominantly thought in terms of Aristotelian concepts and tended to interpret the Bible quite literally. The situation in Sweden was not very different. Finally it is worth mentioning that apparently the process against Galileo in 1633 did not create much interest. It was known but not, as far as I can tell, discussed in print until much later.

Kepler's astronomy was a whole lot more important than Galileo's during this period. Galileo was the first to publish observations about the moons of Jupiter, but others made the same conclusions once they get telescopes. Kepler had a sophisticated mathematical model that was way beyond Tycho's, and Tycho's was way beyond Galileo's. There was no good reason for Danes to pay much attention to Galileo's astronomy. Galileo's confrontation with the Pope made a good story, but scientifically, it wasn't that important.

Born rule is incompatible with many-worlds

Physicist Sean M. Carroll makes another bad attempt at explaining quantum mechanics:

One of the most profound and mysterious principles in all of physics is the Born Rule, named after Max Born. In quantum mechanics, particles don’t have classical properties like “position” or “momentum”; rather, there is a wave function that assigns a (complex) number, called the “amplitude,” to each possible measurement outcome. The Born Rule is then very simple: it says that the probability of obtaining any possible measurement outcome is equal to the square of the corresponding amplitude. (The wave function is just the set of all the amplitudes.)

This is really confused. Particles certainly do have properties like position and momentum. These are observed all the time. The whole idea of a particle accelerator is to put particles in a particular position and particular momentum. They only have these properties when they are observed that way, but then they are not even particles unless they are observed that way.

The description of a wave function is over-simplified. For a system as trivial as one election, the wave function is already more complicated, and the probability is not just the square of the probability.

More importantly, once you accept the quantum mechanics premise that observables are operators on a Hilbert space, then there is nothing mysterious about the Born rule. There is no other way to make sense out of observables being operators. It is only mysterious to many-worlds advocates like Carroll, because they do not believe in probabilities. They believe that all possibilities happen in alternate universes and that there is no way to quantify those universes.

A comment explains:

As a theory, Many Worlds is in a bad state, and this paper is an example of why.

If someone tells me that there are many quantum worlds in a single wavefunction, I expect that they can tell me exactly what part of a wavefunction is a world, and how many worlds there are in a given wavefunction.

As Sean says in his article, a naive attempt to be concrete about what a world is, and how many there are in a given wavefunction, leads to something which *disagrees* with experiment.

But rather than regard this as a point against Many Worlds, and rather than try new ways to carve up the wavefunction into definite worlds… instead we have contorted sophistical arguments about how you should *think* in a multiverse, as the explanation of the Born rule.

The intellectual decline comes when people stop regarding Born probabilities as frequencies, and stop wanting a straightforward theory in which you can “count the worlds”.

Common sense tells me that if A is observed happening twice as often as B, and if we are to believe in parallel universes, then there ought to be twice as many universes where A happens, or where A is seen to happen. But a detailed multiverse theory in which this is the case is hard to construct (Robin Hanson is one of the few to have tried).

Instead what we are getting (from Deutsch, from Wallace, now here) are these rambling arguments about decision theory, rationality, and epistemology in a multiverse. They all aim to produce a conclusion of the form, “you should think that A is twice as likely as B”, without having to exhibit a clear picture of reality in which A-worlds are twice as *common* as B-worlds.

Lumo picks Carroll apart in greater detail, and concludes:

I am really annoyed by the proliferation of this trash and I am annoyed by the fact that this trash is being repetitively pumped into the public discourse by the media and blogs run by narcissist crackpots like Sean Carroll, building upon Goebbels' claim that a lie repeated 100 times becomes the truth. At the end, the reason why I am so annoyed is that people don't have time to appreciate the clever, precious, consistent, and complete way how Nature fundamentally describes phenomena, and the people – like Heisenberg et al. – who have found those gems. These people are the true heroes of the human civilization. Instead, we're flooded by junk by Carroll-style crackpots whose writings don't make any sense and who are effectively spitting on Heisenberg et al.

He is over-the-top, as usual, but he is right that this advocacy of many-worlds is crackpot stuff.

New Poincare scientific biography

There is a new review of Henri Poincare: A Scientific Biography:

Poincaré was, with the possible exception of Hilbert, the deepest, most prolific, and most versatile mathematician of his time. His collected works fill eleven large volumes, and that does not include several volumes on mathematical physics and another several volumes of essays on science and philosophy for the educated reader. ...

How did Poincaré find himself in non-Euclidean geometry? Bolyai and Lobachevskii developed nonEuclidean geometry in the 1820s, and Beltrami put it on a firm foundation (using Riemann’s differential geometry) in 1868. So non-Euclidean geometry was already old news, in some sense, when Poincaré began his research in the late 1870s. But in another sense it wasn’t. Non-Euclidean geometry was still a fringe topic in the 1870s, and Poincaré brought it into the mainstream by noticing that non-Euclidean geometry was already present in classical mathematics. ...

For most of his career, Poincaré was as much a physicist as a mathematician. He taught courses on mechanics, optics, electromagnetism, thermodynamics, and elasticity, and contributed to the early development of relativity and quantum theory. He was even nominated for the Nobel Prize in physics and garnered a respectable number of votes. ...

Another interesting thread that runs through the book is Poincaré’s interest in physics, particularly his near-discovery of special relativity. Gray shows how Poincaré took many of the right steps, starting from Maxwell’s equations and getting as far as introducing the Lorentz group. But he lacked Einstein’s physical insight, and the mathematical insight that could have made up for this, Minkowski’s space-time, was not yet available. As Gray memorably puts it (p. 378):

For Poincaré ... to have grasped the full implications of special relativity he would have had to be not Einstein, but Minkowski.

It is funny how these authors go out of their way to praise Einstein, even when the comments do not make any sense. Any discussion of special relativity always credits Einstein as the discoverer.

While he says that Poincare lacked Eintein's insight, he also says that Poincare grasped it all except for Minkowski’s space-time.

Since Poincare had more of the theory than Einstein, the only way to credit Einstein is to claim that Poincare was deficient in some way. Sometimes the claim is that he did not understand what he wrote. In this review, the argument is that he did not explain what Minkowski wrote 3 years later, and which Einstein did not even understand until about 5 years later.

Poincare and Einstein both published their big special relativity papers in 1905, with Poincare announcing his results first. Minkowski published his famous papers in 1907 and 1908, based on Poincare, not Einstein. Minkowski's 1908 paper emphasized non-Euclidean geometry, and that was what caused relativity to catch on among physicists.

Poincare's 1905 paper had space and time united in a 4-dimensional spacetime, the Lorentz group and algebra as a 4D symmetry, 4-vectors, and the covariance of Maxwell's equations. In short, he presented relativity as a non-Euclidean geometry. Einstein had none of this and did not even mention it in a relativity survey paper he wrote a year later.

Minkowski extended Poincare's geometry with Minkowski diagrams and worldlines. Again, Einstein had none of this, and admitted that he did not understand it.

The book credits Poincare with seeing the gravitational implications in 1905, but suggests that he might have had an epistemological confusion by failing to distinguish between the length of a measuring rod, and what he measures the length of a measuring rod to be. That is, distinguishing the actual length from the apparent length. Overbye's Einstein book also mentioned this distinction.

But you can check the papers yourself for this distinction. Einstein does not make it in his famous 1905 paper. Poincare does in his long 1905 paper:

Or this part which would be, so to speak, common to all the physical phenomena, would be only apparent, something which would be due to our methods of measurement.

Poincare explains how this new view is different from Lorentz's, but Einstein never made any such claim.

Poincare's special relativity was vastly superior to Einstein's work in every aspect. This is detailed in my book, How Einstein Ruined Physics. Einstein is only credited with nonsensical arguments.

Aaronson sarcastic about quantum info in 2040

Scott Aaronson writes an article on How Might Quantum Information Transform Our Future?:

Picture, if you can, the following scene. It’s the year 2040. You wake up in the morning, and walk across your bedroom to your computer to check your email and some news websites. Your computer, your mail reader, and your web browser have some new bells and whistles, but all of them would be recognizable to a visitor from 2014: on casual inspection, not that much has changed. But one thing has changed: if, while browsing the web, you suddenly feel the urge to calculate the ground state energy of a complicated biomolecule, or to know the prime factors of a 5000-digit positive integer — and who among us don’t feel those urges, from time to time? — there are now online services that, for a fee, will use a quantum computer to give you the answer much faster than you could’ve obtained it classically. Scientists, you’re vaguely aware, are using the new quantum simulation capability to help them design drugs and high-efficiency solar cells, and to explore the properties of high-temperature superconductors. Does any of this affect your life? Sure, maybe it does — and if not, it might affect your children’s lives, or your grandchildren’s. At any rate, it’s certainly cool to know about. ...

As magical as it all sounds, this is the wondrous science-fiction future that my sixteen years of research in quantum computing and information lead me to believe is possible. Assuming, of course, that we actually do build scalable quantum computers.

So even if scalable quantum computers are invented, the impact on our lives will be negligible.

I guess he is being sarcastic here, so it is hard to tell whether he thinks quantum computers will ever be possible, or whether he is making fun of those who do. He alternates between over-hyping the subject, and criticizing those who do.

Predicting the future is tricky, of course, but computer technology has been on a stable predictable path for a long time. Processing power has followed Moore's Law for 50 years. Artificial intelligence, such as voice and image recognition, has progressed more or less on schedule. Some say that we are headed for the Singularity around 2040. That seems optimistic to me, but they are not even assuming quantum computer benefits.

But there is still no experiment demonstrating that quantum computers are feasible, and I doubt that there ever will be.

I agree with Gil Kalai:

I find the article entertaining and enjoyable in spite of me being one of the “skeptics” who think that superior computation through quantum computers is not possible. (And I really mean “not possible” :) .) ... Of course, impossibility of computationally superior quantum computing is not in conflict with quantum mechanics.

Even if quantum computers are possible, the main application will be destructive -- breaking our current computer security and requiring complicated and expensive work-arounds to achieve what is easy today.

Aaronson adds:

To be honest, I have no idea whether QKD will ever find a significant market or not. But at least the technology already exists (and “works,” over short enough distances), if a nontrivial market were ever to develop.

It’s true that there are classical cryptosystems that are probably secure even against quantum computers. However, the trouble is that all such systems currently known are either
(a) private-key, and hence cumbersome to use, or else
(b) public-key systems like the lattice-based systems, which currently require key sizes and message sizes large enough to make them impractical for most applications.

Of course, it’s possible that more practical quantum-secure public-key cryptosystems will eventually be discovered. Certainly lots of people have been thinking about that. But if no such systems are discovered, and if (on the other side) the technology of QKD were to improve so that it could handle much higher bit-rates and distances, then there really could be a good use case for QKD.

Quantum key distribution will probably never have any practical utility. Sure it works, but much simpler methods give much better security.

Myth of the lone genius

Joshua Wolf Shenk writes in a NY Times op-ed:

But the lone genius is a myth that has outlived its usefulness. Fortunately, a more truthful model is emerging: the creative network, ...

Today, the Romantic genius can be seen everywhere. Consider some typical dorm room posters — Freud with his cigar, the Rev. Dr. Martin Luther King Jr. at the pulpit, Picasso looking wide-eyed at the camera, Einstein sticking out his tongue. These posters often carry a poignant epigraph — “Imagination is more important than knowledge” — but the real message lies in the solitary pose.

In fact, none of these men were alone in the garrets of their minds. Freud developed psychoanalysis in a heated exchange with the physician Wilhelm Fliess, whom Freud called the “godfather” of “The Interpretation of Dreams”; King co-led the civil rights movement with Ralph Abernathy (“My dearest friend and cellmate,” King said). Picasso had an overt collaboration with Georges Braque — they made Cubism together — and a rivalry with Henri Matisse so influential that we can fairly call it an adversarial collaboration. Even Einstein, for all his solitude, worked out the theory of relativity in conversation with the engineer Michele Besso, whom he praised as “the best sounding board in Europe.”

Freud's dream theory? That stuff is nonsense, and Freud was a crackpot, not a genius.

Besso? Maybe he is the only one that Einstein honestly thanked, but his work depended on many others.

When people talk about Einstein as a lone genius, they are usually talking about his 1905 special relativity paper, or maybe the 1905 photon paper. His later work on general relativity is better documented, and is well-known that he very heavily relied on Grossmann, Levi-Civita, Hilbert, and others.

The 1905 papers were supposed done in isolation, while working at the Swiss patent office. But he had the papers of Lorentz and Poincare, and his relativity paper had no new ideas that are not explained better by them.

The myth that Einstein worked in isolation has promoted the idea that a lone genius can ponder ideas that were known for 50 years, look at them differently, and revolutionize physics. Even philosophers and historians of science perpetuate this Einstein myth. Einstein's paper was merely a presentation of recent research.

Voigt discovered Lorentz transformations

There is a new paper on the history of special relativity, titled The wave equation in the birth of spacetime symmetries:

Woldemar Voigt published in 1887 the article [1]: “On Doppler’s Principle” which has unfortunately received little recognition by physicists and historians of physics [2–6]. Apparently, he was the first — or at least one of the firsts — who demanded form invariance of a physical law to obtain a set of transformation equations. This remarkable idea began the search for physical symmetries in field theories. More precisely, Voigt demanded form invariance of the homogeneous wave equation in inertial frames and obtained a set of spacetime transformations now known as the Voigt transformations ...

In the creation of special relativity, we traditionally find the names of Lorentz, Larmor, Poicar´e and Einstein. They appear to be the main actors. Voigt is relegated to being a minor player, in the best of cases. But this tradition is not faithful to the history of physics, since Voigt was the first in applying the two postulates of special relativity. He deserves a place in textbooks. The idea of demanding that the wave equation should not change its form when observed by different inertial frames, was the great conceptual contribution of Voigt, since it opened the gate to the world of physical symmetries. This is the legacy of Voigt’s 1887 paper.

Voigt's transformations were not exactly the same as the Lorentz ones, and he did not have some of the other essential relativity breakthrus of Lorentz and Poincare.

Deducing symmetries from equations of physics became one of the great ideas of XX century physics. Voigt was a pioneer in 1887.

Connecting the aether to hidden variable theories

I often post on how people get the history of relativity wrong, and how they misinterpret quantum mechanics. Sometimes these are related, as in this essay:

To begin with, it is crucial to make a distinction between two different senses in which a theory might be said to be "relativistic". First, a theory might be empirically relativistic. This means that what it predicts for the outcomes of experiments will exhibit the usual relativistic properties — for example, it should predict the familiar relativistic behavior of clocks and meter sticks in relative motion. More generally, it should agree with classical relativistic mechanics about the behavior of macroscopic objects and it should predict (ignoring for the moment gravitation and general relativity) that an experimenter cannot tell whether an appropriately isolated laboratory has been set into uniform motion.

Despite the central role it is given in certain philosophies of science, however, observation is not everything. We thus need to recognize (at least) a second sense in which a theory might be said to be "relativistic" — namely, that it is compatible with relativity through and through, and not just at the (relatively superficial) level of empirical predictions. Such a theory will be said to be fundamentally relativistic. To make the distinction clear, it is helpful to contrast two different versions of classical electromagnetism. Let us call these the Lorentzian and the Einsteinian theories.

According to the Lorentzian theory, there is a physically meaningful notion of absolute rest (defined by the so-called "ether" rest frame) and a physically meaningful notion of absolute time. These correspond to the existence of a preferred family of coordinate systems over spacetime and the dynamics of the theory is defined, with respect to these coordinate systems, by the usual equations of electromagnetism. ...

By contrast, the Einsteinian version of classical electromagnetism is of course relativistic, not just empirically, but fundamentally. The notion of a really-existing but unobservable "ether" rest frame is dispensed with and all uniform states of motion are regarded as equivalent.

Sometimes it is thought (and taught) that certain experiments from the late 19th or early 20th century refuted the Lorentzian theory in favor of the Einsteinian one. But this is not correct. With regard to their empirical predictions, there is no difference between the Lorentzian and Einsteinian theories. ...

For our purposes, there are three important lessons here. The first is that the empirical violation of Bell-type inequalities does not require theories that fail to be empirically relativistic. But this is hardly sufficient to assuage the worry: if empirical relativity is the only kind of relativity that can be saved, it's not clear that relativity, in any substantial sense, is being saved. The second lesson is thus that, if we want to insist on preserving compatibility with relativity, it is fundamental relativity (not mere empirical relativity) that we must insist on.

But the third lesson is that perhaps abandoning fundamental relativity should be on the table as a serious option. Doing so would not necessitate empirical predictions at odds with the experimental results that are normally taken to support relativity. And it is clear that the use of a dynamically preferred but unobservable "ether" frame would make it very easy for theories to incorporate the non-local interactions that Bell's theorem (and the associated experiments) require.

Lorentz never said that there was a "physically meaningful notion of absolute rest" or a "physically meaningful notion of absolute time." After all, he achieved empirical relativity, so what would the physical meaning be?

This distinction between the Lorentzian and Einsteinian theories is an entirely modern invention, and a nonsensical one. In 1906, it was called the Lorentz-Einstein theory, and no one noticed any difference. There is some point in writing physics in covariant equations, but Poincare and Minkowski added that to special relativity, not Einstein.

There is no difference between a theory with a preferred frame, and one without one. Mathematically, a space is called a manifold if it has no preferred frame, but textbooks often define a manifold in terms of a particular frame. It is obvious that it makes no difference.

Some people, like Einstein, Bell, and the authors of the above essay have a strange belief that somehow quantum mechanics will make more sense if it more directly refers to unobservable hidden variables. It is live believing in an unobservable aether. Bell actually said that relativity makes more sense that way.

The above essay is wrong when it says that Bell's theorem requires nonlocal interactions. And it is crazier still to think that some trivial choice of frame for the aether will somehow make those interactions more comprehensible. If anything, Bell's theorem says that hidden variable cannot help understand certain quantum paradoxes. They are better explained by orthodox quantum mechanics.