{"id":81,"date":"2008-11-22T17:19:37","date_gmt":"2008-11-22T22:19:37","guid":{"rendered":"http:\/\/blog.richmond.edu\/physicsbunn\/2008\/11\/22\/thomas-bayes-says-that-i-shouldnt-believe-in-hydrinos\/"},"modified":"2008-11-22T17:19:37","modified_gmt":"2008-11-22T22:19:37","slug":"thomas-bayes-says-that-i-shouldnt-believe-in-hydrinos","status":"publish","type":"post","link":"https:\/\/blog.richmond.edu\/physicsbunn\/2008\/11\/22\/thomas-bayes-says-that-i-shouldnt-believe-in-hydrinos\/","title":{"rendered":"Thomas Bayes says that I shouldn’t believe in hydrinos"},"content":{"rendered":"

My recent post<\/a> about Blacklight Power’s claim that there’s a lower-energy state of hydrogen (which they call a hydrino) seems to have gotten a bit of interest — at least enough to show that this blog isn’t completely a form of write-only memory<\/a>. I want to follow up on it by explaining in a bit more detail why I’m so skeptical of this claim.\u00a0 In the process, I’ll say a bit about Bayesian inference.\u00a0 The idea of Bayesian inference is, in my opinion, at the heart of what science is all about, and it’s a shame that it’s not talked about more.<\/p>\n

But before we get there, let me summarize my view on hydrinos.\u00a0 If Randell Mills (the head of Blacklight Power, and the main man behind hydrinos) is right, then the best-tested theory in the history of science <\/em>is not merely wrong, but really really wrong.\u00a0 <\/em>This is not a logical impossibility, but it’s wildly unlikely.<\/p>\n

Let me be more precise about the two italicized phrases in the previous paragraph.<\/p>\n

1. “The best-tested theory in the history of science.<\/em>”\u00a0 <\/strong>The theory I’m talking about is quantum physics, more specifically the quantum mechanics of charged\u00a0 particles interacting electromagnetically, and even more specifically the theory of quantum electrodynamics (QED).\u00a0 Part of the reason for calling it the best-tested theory in science is some amazingly high-precision measurements, where predictions of the theory are matched to something like 12 decimal places.\u00a0 But more important than that are the tens of thousands of experiments done in labs around the world all the time, which aren’t designed as tests of QED, but which depend fundamentally on QED.<\/p>\n

Pretty much all of atomic physics and most of solid state physics (which between them are a substantial majority of physics research) depends on QED.\u00a0 Also, every time an experiment is done at a particle accelerator, even if its purpose is to test other physics, it ends up testing QED. This has been true for decades.\u00a0 If there were a fundamental flaw in QED, it is inconceivable that none of these experiments would have turned it up by now.<\/p>\n

2. “Really really wrong.<\/em>“<\/strong>\u00a0 There’s a hierarchy of levels of “wrongness” of scientific theories.\u00a0 For instance, ever since Einstein came up with general relativity, we’ve known that Newton’s theory of gravity was wrong: in some regimes, the two theories disagree, and general relativity is the one that agrees with experiment in those cases.\u00a0 But Newtonian gravity is merely wrong, not really really wrong<\/em>.<\/p>\n

It’s intuitively clear that there’s something deeply “right” about Newtonian gravity — if there weren’t, how could NASA use it so successfully (most of the time<\/a>) to guide space probes to other planets?\u00a0 The reason for this is that Newtonian gravity was subsumed, not replaced, by general relativity.\u00a0 To be specific, general relativity contains Newtonian gravity as a special limiting case.\u00a0 Within certain bounds, Newton’s laws are a provably good approximation to the more exact theory.\u00a0 More importantly, the bedrock principles of Newtonian gravity, such as conservation of energy, momentum,\u00a0 and mass, have a natural place in the broader theory.\u00a0 Some of these principles (e.g., energy and momentum conservation) carry over into exact laws in the new theory.\u00a0 Others (mass conservation) are only approximately valid within certain broad limits.<\/p>\n

So Newtonian gravity is an example of a theory that’s wrong but not really really wrong<\/em>.\u00a0 I would describe a theory as really really wrong<\/em> if its central ideas were found to be not even approximately valid, in a regime in which the theory is well-tested.\u00a0 The existence of hydrinos would mean that QED was really really wrong in this sense.\u00a0 To be specific, it would mean that bedrock principles of quantum physics, such as the Heisenberg uncertainty principle, were not even approximately valid in the arena of interactions of electrons and protons at length scales and energy scales of the order of atoms.\u00a0 That’s an arena in which the theory has been unbelievably well tested.<\/p>\n

There has never been an instance in the history of science when a theory that was tested even 1% as well as QED was later proved to be really really wrong.\u00a0 In fact, my only hesitation in making that statement is that it’s probably a ridiculous understatement.<\/p>\n

So what?<\/em><\/strong>\u00a0 In the cartoon version of science, even one experiment that contradicts a theory proves the theory to be wrong.\u00a0 If Randell Mills has done his experiment right, then quantum physics is wrong, no matter how many previous experiments have confirmed it.<\/p>\n

The problem with this cartoon version is that results of experiments are never 100% clear-cut.\u00a0 The probability that someone has made a mistake, or misinterpreted what they saw, might be very low (especially if an experiment has been replicated many times and many people have seen the data), but it’s never zero.\u00a0 That means that beliefs about scientific hypotheses are always probabilistic beliefs.<\/p>\n

When new evidence comes in, that evidence causes each person to update his or her beliefs about the probabilities of various hypotheses about the world.\u00a0 Evidence that supports a hypothesis causes us to increase our mental probability that that hypothesis is true, and vice versa. All of this sounds obvious, but it’s quite different from the black-and-white cartoon version that people are often taught.\u00a0 (I’m looking at you, Karl Popper<\/a>.\u00a0 Falsifiability?\u00a0 Feh.)<\/p>\n

All of this brings us at last to Bayesian inference<\/em><\/strong>.\u00a0 This is the systematic way of understanding the way that probabilities get updated in the light of new evidence.<\/p>\n

Bayes’s Theorem relates\u00a0 a few different probabilities to each other:<\/p>\n