Making the Kessel Run in Under 12 Parsecs

From xkcd, by Randall Munroe.

On the OPERA neutrino experiment, the conservative war on relativity, and the operation of science (with a nod to the biggest science boo-boo in Star Wars).

One can understand, if not necessarily agree with, the conservative war on the Theory of Evolution. If you believe that a specific book must be taken literally, and that book states that the Earth was created in seven days, then it is impossible for Darwinian evolution to have taken place. Either the book in question is not literally true, or the theory must be wrong. You can’t have both.

I must admit, though, to being perplexed by the conservative opposition to the Theory of Relativity. I first encountered this when one of my White House speechwriter friends asked me to review an unpublished manuscript ostensibly debunking Einstein. (It was written by a political science major.) The book was filled with bold assertions, dismissal of contrary evidence, and an ongoing hint that relativity was enthroned not because of its merits as a theory, but because of an ongoing conspiracy by what xkcd refers to as the “Science Thought Police.” In other words, it was just like the anti-evolution arguments.

The objection to relativity seems to rest on a semi-religious foundation: the idea that reality is in some sense objective, without uncertainty or variability. There’s an existential threat in the idea that some parts of reality are subjective, variable, or…well, relative. More importantly, the objection goes to the heart of the idea of science itself, the idea that the experimental method, peer review, and testable hypotheses can separate the valid from the invalid. For those whose authority rests on a foundation of “truth,” testability can be quite inconvenient.

Which brings us to the OPERA neutrino experiment, in which the underground Gran Sasso Laboratory measured the velocity of neutrinos from CERN at moving slightly faster than the speed of light (c). The difference is not great — 60 nanoseconds faster over a distance of 730 kilometers (with an expected error of ±10 nanoseconds) — but any evidence that a particle can exceed the speed of light forms a huge challenge to the foundations of modern theoretical physics. (For the curious, the official paper can be found here.)

Not so fast. The researchers themselves have not made any claims so bold. Before publishing, they looked for experimental errors. They re-ran the experiment. They looked at a variety of potential explanations and controlled for as many variables as they could. By publishing the results, they aren’t making the claim that they’ve refuted Einstein, but rather quite the opposite: they are appealing to the scientific community to repeat the experiment and see if they can discover why the OPERA results are incorrect.

That’s as it should be. Given the overwhelming body of evidence post-Einstein that confirms the principles of relativity, an anomalous result deserves to be treated with skepticism. Extraordinary claims, as they say, require extraordinary proof.

In fact, there’s already a strong experimental case that undercuts the OPERA results. On February 23, 1987, light from a supernova in the Large Magellanic Cloud, one of the two dwarf galaxies that orbit our own Milky Way, reached Earth after traveling approximately 168,000 light years. It was the closest supernova to Earth since Kepler’s Supernova of 1604, and the first since then to be visible to the naked eye.

About three hours before the visible light from SN1987A reached Earth, neutrino bursts were observed at three different neutrino observatories. This doesn’t mean those neutrinos traveled faster than light; the visible light produced by a supernova’s collapsing core has to travel upward to the stellar surface, while neutrinos zip right through the intervening material. If those neutrinos were traveling as fast as the OPERA observations indicate (60 ns per 730 km), the neutrino bursts should have arrived nearly four years before the visible light.

What, then, do the OPERA results mean? One possibility — the likeliest, according to most blogging scientists I’ve been reading in the past few days — is that a measurement error did in fact occur. If there’s not a measurement error, and it turns out that the neutrinos do move slightly faster than our current measurement of c, it still won’t “refute” Einstein -- our GPS units (which rely on relativity equations) still work. Einstein, after all, didn’t “refute” Isaac Newton. Newton’s laws work quite well in the majority of cases. It’s only at extreme speeds and under unusual conditions that relativistic differences matter.

What it will mean, if the results hold up under scrutiny, is that adjustments will be made. The models we use to understand the universe will require modification, becoming more accurate. There’s a small chance we’ll discover some important breakthrough that changes our understanding of the universe in materially significant ways.

In that case, the better parallel will be the 1887 experiments by Albert Michelson and Edward Morley involving the measurement of the speed of light in different directions, with the goal of measuring the motion of the Earth with respect to the luminiferous aether. They also didn’t get the results their theory predicted. The difference here was also small enough to be attributed to experimental error, but over time, as the results became more and more solid, it finally became clear that there was something wrong with the aether hypothesis. 

Although Einstein’s theory of relativity did not rest on “science’s most famous failed experiment,” Michelson-Morley did serve as evidence that helped the new theory of a constant speed of light gain widespread acceptance.

Weak Faith, Strong Faith

As the old joke goes, when the only tool you have is a hammer, all problems look like nails. Applying a single frame to a variety of problems is one of the underlying characteristics of many cognitive biases. Science, law, and faith are three popular frames that cover complex and contentious issues ranging from abortion to evolution, from global warming to the value of prayer in the schools. Let’s look at how they work.

Science bears the same relationship to knowledge as law does to justice. It’s a process, and as such inherently imperfect. To compensate for its imperfections, we choose certain biases. In American law, “innocent until proven guilty” is such a bias. It’s a deliberate attempt to make errors fall more heavily in one direction than another. The injustice of allowing some guilty people to escape is, we believe, less than the injustice of imprisoning an innocent person. The appeals process supplies quality assurance and quality control. Even so, mistakes occur. Law does not provide perfect justice.

The process of science is based on the experimental method. Through repeatable experiments, we test hypotheses. From the results, we develop theories, and those theories are tested in turn. Over time, the scientific community reaches a consensus, and that’s the state of scientific knowledge at a particular point in time. Inertia applies: it takes a lot of work and effort to build a case that will persuade the scientific community to accept a change, but once the change is accepted, it tends to stay accepted.

The burden of proof necessarily rests on the side challenging the consensus. That’s only fair and proper. Suggesting the entire scientific community professes a certain position because they’re either suffering from mass delusion or outright corruption strains credulity. Saying they’re wrong, on the other hand, is fair game — if you have the evidence to back it up. And the scientist who successfully overturns the consensus apple cart to create a new paradigm goes down in the history books. That’s a powerful incentive for change.

We must remember, on the other hand, Carl Sagan’s dictate, “The fact that some geniuses were laughed at does not imply that all who are laughed at are geniuses. They laughed at Columbus, they laughed at Fulton, they laughed at the Wright brothers. But they also laughed at Bozo the Clown.” Science does not provide perfect knowledge.

I seldom take the time to study all the scientific literature on any issue, and in many areas would be unable to analyze it properly if I did. Nor do I take the time to study the details of a legal case prominent in the papers, and often don’t know the underlying law well enough to analyze it correctly if I did. I have to take the results on faith.

Faith can be a bright, shining beacon of certainty in a murky world, or it can be a weak thing, provisional and tentative. The first kind of faith trumpets itself as the possessor of Truth Revealed. (Or as Mark Twain puts it, “[Man is] the only one who’s got the true religion — several of them.”). The idea of certainty fills a deep-seated human need, and I understand the temptation. Uncertainty is inherently uncomfortable. The gospel of peace is the comfort of knowing. But faith, any more than science or law, does not reliably produce perfect truth.

Provisional faith is faith without certainty. Yes, perhaps all of reality could be an elaborate illusion, but that’s not the way to bet. We each make hundreds of assumptions as we go through each day, and we have no practical choice in the matter. Faith in some things is not an option. On the other hand, we’ve been wrong before. Like law and science, faith requires biases to work, along with a skeptical mind to provide checks and balances.

In place of justice, we have law. In place of knowledge, we have science. In place of truth, we have faith. Certain faith is easily visible in the religious sphere, but true believers are found in science and law and in every other discipline that attempts to standardize the chaos of reality.

Faith has a fundamental place in human affairs, but a weak and skeptical faith is worthy of more respect than the strong and bright kind. When someone is strong in his or her faith, certain of his or her rightness, absolute in knowledge of Truth, it's time to hold onto your wallets. Unchecked, the gospel of certainty become the opiate of its adherents.

Comfort can come at far too high a price.