Hits and Misses of the Physicist Bloggers

For decades the late Stephen Hawking was the center of a kind of giant hype machine that portrayed him as the greatest living scientific genius. This hype was unwarranted for a scientist who never even won a Nobel Prize. Showing admirable persistence and diligence despite his severe handicaps, Hawking made some interesting contributions to the study of black holes. But his thoughts about topics outside of his specialty were often not very wise.

An example of his dubious thinking was his “No Boundary Proposal” about the Big Bang, that the Big Bang was not a boundary in space or time. The problem with this proposal is that it is the exact opposite of what nature tells us about the beginning. Everything we have learned about the Big Bang suggests it is as clear a boundary as you can imagine, a sudden beginning of time and space.

Hawking also repeatedly warned that machines might take over the world (a fear that is unwarranted for the reasons  discussed here).  He repeatedly urged that we need to leave planet Earth (not as good an idea as staying here and making sure that our planet stays in good health). He repeatedly sung the praises of M-theory, a wildly speculative theory for which no evidence has ever appeared. He also declared falsely and unwisely that “philosophy is dead.”

Physicist blogger Ethan Siegel (whose specialty is cosmology) has a post entitled “The 4 Scientific Lessons Stephen Hawking Never Learned.” He lists one of these lessons as “Be humble about your own speculative, unproven ideas.” He states the following:

This is a pitfall that has afflicted many of the greatest minds throughout scientific history: to fall in love with their own fringe scientific ideas so thoroughly that you tout them with the certainty normally reserved for verified, validated, robust theories. Hawking's no-boundary proposal is speculative and unproven, yet Hawking will often (including in A Brief History Of Time) speak about it with the same certainty he'd speak about black holes....Unproven ideas should never be a substitute for legitimate facts, yet Hawking, in every book he ever wrote, never tells you when he strays from the confirmed-and-validated into this speculative realm, particularly where his own ideas are concerned.

Here Siegel is right on the mark. One of the greatest problems of modern scientific literature is that writers mix up speculations and established facts, packaging the whole mixture as “science.” And so many a dubious proposition and many a doubtful theory is sold to the public as “science,” as if such things were well-established. Such failure to distinguish between fact and theory goes on constantly in the literature of biology, psychology, physics, and cosmology. When people start a sentence with “Science says,” half of the time they will refer us to something that has not actually been established by observations or experiments. 

 

Unfortunately, Siegel himself is often guilty of exactly this problem of falling in love with his own shaky scientific ideas so thoroughly “that you tout them with the certainty normally reserved for verified, validated, robust theories.” We see this repeatedly in his columns when he refers to the extremely speculative and very much unverified theory of cosmic inflation as if it were empirically established science, which it certainly is not. We also see this repeatedly when Siegel refers to the speculative theory of dark matter as if it were empirically established, which it is not. No one has ever directly observed any dark matter. In the same column that Siegel is criticizing Hawking for speculative excess, he refers to “everything we've learned since 1979 about the conditions that set up the Big Bang.” Nothing of the sort has actually been learned, and we know nothing whatsoever about any conditions that set up the origin of the universe.

Not only do we have no observations about anything occurring any time close to the Big Bang, but we have no observations (and will never be able to have any observations) of anything that occurred in the first 300,000 years of the universe's history. Scientists tell us that it was only at about 300,000 years after the Big Bang that there occurred what is called the Recombination Era, in which atoms first formed. During the first 300,000 years, particles were so densely packed that all light coming from those years must have been hopelessly scattered. As a scientific site tell us:

Because of the presence of the free electrons, photons were scattered around in all directions and could not travel far before changing their direction. Therefore the universe was "opaque".

We therefore will never be able to get any observations about anything that happened during the universe's first 300,000 years. The light from those years was hopelessly jumbled and scrambled by the density of the matter, as strongly as if you put your Microsoft Word document through a computer program that might thoroughly scramble its characters 100,000 times. As we will never be able to make observations of the universe's state in the first 300,000 years, all claims about the exact state at the Big Bang (or before it) will never be claims backed up by observations.

A physicist blogger with a large following is Lubos Motl, who has been blogging many times a month since 2004 at his site "The Reference Frame."  Motl's blog is a strange collection of physics, politics, and climate commentary, with many of his opinions being very dubious (but presented with a large amount of literary skill and style). Very strangely Motl is for supersymmetry (a theory for which there is no evidence), but opposed to standard ideas on global warming (for which there is a great deal of evidence). This is simply an example of how the assertions of a modern scientist may be very largely dependent on the scientist's personal tastes. On the plus side, I may note that Motl is a good person to have around when physicists start spouting nonsense about parallel universes, because he has shown his skill at debunking such speculations.

Another physicist blogger with some interesting content is Sabine Hossenfelder, who blogs at this site. In contrast to Motl, she has repeatedly criticized the theory of supersymmetry, a speculative physics theory. That seems appropriate, since all signs are that supersymmetry has been a great big waste of time. Thousands of scientific papers have been written advancing this ornate speculative theory for which no evidence has been gathered.

But Hossenfelder has repeatedly advanced a dubious account as to why physicists advanced the supersymmetry theory. She has often claimed that the theory was advanced because physicists find that supersymmetry is “prettier” or “more beautiful.” Referring to the supersymmetry theory in a recent post, she says,  “I explained many times previously why the conclusions based on naturalness were not predictions, but merely pleas for the laws of nature to be pretty.”

But it's not correct that the supersymmetry theory was advanced because physicists had some great longing for a beautiful or pretty theory. The supersymmetry theory (a very cluttered affair not at all beautiful) was advanced to explain away a particular case of fine-tuning in the laws of physics.

Here is how the wikipedia.org article on supersymmetry explains it:

In the Standard Model, the electroweak scale receives enormous Planck-scale quantum corrections. The observed hierarchy between the electroweak scale and the Planck scale must be achieved with extraordinary fine tuning. In a supersymmetric theory, on the other hand, Planck-scale quantum corrections cancel between partners and superpartners (owing to a minus sign associated with fermionic loops). The hierarchy between the electroweak scale and the Planck scale is achieved in a natural manner, without miraculous fine-tuning.

So the real reason the supersymmetry theory was advanced was to try to avoid a case of “miraculous fine-tuning.” This is a much different reason than creating a theory in hopes of making the laws of nature “be pretty.”

No evidence has shown up for the supersymmetry theory. So scientists are stuck with this case of “miraculous fine-tuning” they had hoped to avoid. In a previous post, Hossenfelder compared this particular case of fine-tuning to finding a cube balanced on one of it edges. She says she doesn't believe that “finetuned parameter values require additional explanation.” In that post she seems to speak as if she thinks people should not pay much attention to cases in physics where we find a cosmic balance so delicate that it's like a cube balanced on one of its edges. I disagree, and think that such cases (which must have an explanation other than chance) are weighty cosmic clues we should pay very much attention to.

Postscript: In a recent interview in Scientific American, cosmologist Martin Rees says that the cosmic inflation theory (not to be confused with the more general Big Bang theory) is a "good bet."  But we should call things a "good bet" only when we have some probabilistic basis for believing in their likelihood. For example, if you hear a 60-year-old suddenly died in his home, it would be a good bet that he died of a heart problem, because that's the most common cause of sudden deaths in the elderly. But there is no probabilistic basis whatsoever for calling cosmic inflation (a brief burst of exponential expansion of the universe) something likely to have occurred. For such a thing to occur (ending up with a universe like ours) requires so many special conditions and so much fine-tuning that it is wrong to be calling such a theory  "a good bet." The theory is better described as a "popular story."

At her blog Sabine Hossenfelder puts the cosmic inflation theory into context:

Theoretical physicists have proposed some thousand ideas for what might have happened in the early universe. There are big bangs and big bounces and brane collisions and string cosmologies and loop cosmologies and all kinds of weird fields that might or might not have done this or that. All of this is pure speculation, none of it is supported by evidence.