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Our future, our universe, and other weighty topics


Monday, November 17, 2014

A Scientist's Faulty Theory of Truth

In the last chapter of his book The Truth of Science: Physical Theories and Reality, emeritus professor of physics Roger G. Newton advances a theory of truth. (I will call Mr. Newton by his first name to avoid confusion with the famous physicist named Newton.) Roger advances a coherence theory of truth. In general, such a theory maintains that truth is whatever fits in or meshes with other things that are regarded as true. Roger puts it this way on page 207 of his book: “The most important criterion for ascertaining the truth of a statement is its coherence with a network of assertions that are also regarded as true.”

But there is a potent criticism that can be made against such a theory. Many claimed truths can be fit in with some system of assumptions about what is true, but do not fit in with some other system of assumptions about what is true. So a coherence theory of truth would seem to imply that such claimed truths are both true and false, which doesn't make sense. For example, reincarnation fits in well with a network of assertions made by the average Hindu, but does not fit in with a network of assertions made by Western materialists. So according to a coherence theory of truth, it would seem that assertions of reincarnation or past lives are both true and false.

What Roger clearly wants you to believe is that the real acid test for truth is that it fit in not just with a network of assertions made by some group, but by Western physicists such as himself. He basically seems to be saying that truth is whatever fits in with what him and physicists like him tend to believe to be true.

One problem with such an approach is that modern physical science and scientific opinion is not a monolithic coherent “network of assertions,” all nice and harmonious and factual. Quantum mechanics does not agree with general relativity. Some physicists believe passionately that string theory is the reality behind everything, while many other physicists reject the theory as baseless. Some physicists support the idea of a multiverse or ideas of parallel universes. Other physicists reject such ideas with scorn. There is a great deal of disagreement about different matters. So how can “fitting in with what physicists think” be the acid test for truth, when there is so much disagreement among the physicists themselves?

Roger takes his coherence theory to some imprudent extremes. On the same page in which he makes the key assertion that “the most important criterion for ascertaining the truth of a statement is its coherence with a network of assertions that are also regarded as true,” Roger uses this theory as a justification for rejecting evidence of the paranormal without even examining it: “Researchers justifiably refuse to listen to these claims, to examine them or refute them in detail, because they are incoherent with the rest of our scientific knowledge.” The problems with this attitude are many. First, there is no way in which one could intelligently judge that a particular claim was “incoherent with the rest of our scientific knowledge” without examining the claim in detail, which Roger encourages researchers not to do.

Secondly, it is not obvious that most paranormal claims are “incoherent with the rest of our scientific knowledge.” What is or is not “incoherent with scientific knowledge” is a very debatable, subjective matter. It is, in fact, not at all obvious that most of the more common paranormal claims are actually incompatible with any known laws of nature, as I argue here. What Roger encourages people to do is to ignore classes of observations, not on any objective basis, put purely on the very subjective judgment of whether or not such observations are “incoherent with scientific knowledge,” a type of judgment that might be highly influenced by sociological and psychological factors, and our prejudices and biases.

Roger also almost seems to imply that when you have a choice between believing the testimony of your own senses and fitting in with a “network of assertions” advanced by authorities, you should ignore the testimony of your senses. I say this because he cites the case of a psychologist who claims to have seen a celebrity in his office long after the celebrity's death. “This is not how a scientist arrives at truth,” intones Roger with disapproval. So if you see something with your own two eyes, and you've never had a hallucination before, you should ignore that, because it conflicts with your expectations, and doesn't “fit in with the system” that has been dogmatically taught by authorities? Wrong. Observations should be king, regardless of whether they clash with your expectations.

Roger's “coherence test” for truth seems to be a type of reality filter, with the unfortunate outcome illustrated in the diagram below:





Roger considers for an instant the possibility that “a startling, discordant fact, long ignored by 'the establishment,' may someday be discovered, producing a new paradigm with its own coherence.” But he immediately rejects such a possibility, by arguing that “the body of scientific knowledge, however, is by now so large that this scenario is extremely unlikely.” This is smug intellectual complacency that is very unwarranted. From a cosmic standpoint, what we know is very, very small compared to what we don't know. We know of only a few planets in a vast universe which may have trillions of inhabited planets, and we still don't understand some of the most basic questions involving the origin of the universe, the origin of cosmic structure, the origin of life, and the origin of consciousness. We are puzzled by a thousand mysteries of time, space, and Mind that we haven't figured out. An extraterrestrial species might look at us as we might look at little children playing at the sea shore, trying to figure out the ocean from the waves and the shells. Looked at from such a perspective, our knowledge of things is very fragmentary and very small, not “so large” as Roger argues. So the “new paradigm” scenario Roger mentions is very plausible, not “extremely unlikely” as Roger argues.

One problem with Roger's approach is that only part of the “network of assertions” made by modern physicists is actually fact. There is also a great deal of theory being asserted, much of it wild and speculative (physicists these days love to advance all kinds of extremely weird theories). Then there are also quite a few assertions that come under the category of “widely held assumptions” that have no direct scientific support, such as claims that the universe is entirely random, or claims that all consciousness can be explained by brain activity (no one has ever published a scientific paper proving either assumption). It is a nightmare to sort out which parts of the modern scientist's “network of assertions” is fact, which is theory, and which is personal opinion advanced more out of a sociological kind of peer group conformity than scientific necessity. So how could “coherence” with such a network of assertions be a reliable basis for judging truth – particularly since “coherence” is a vague, wooly, subjective term, incapable of being objectively measured, without any of the precision that scientists like to have?

It's easy to imagine examples that show that a coherence theory of truth doesn't work. Let us imagine that some astronomical analysis software has a bug, and because of the bug a scientist who is analyzing a distant solar system concludes mistakenly that such a solar system has an Earth-sized planet. Then let us imagine that a second scientist in another country uses the same buggy software to analyze that distant solar system, and therefore draws the same incorrect conclusion that such a solar system has an Earth-sized planet. According to a coherence theory of truth, the second scientist must have stated a true assertion – because his assertion not only has excellent coherence with other scientists finding Earth-sized planets, but also good coherence with the previous scientist concluding that there was an Earth-sized planet at the particular distant solar system the second scientist analyzed. But, in fact, the second scientist has not made a true conclusion, because there is no Earth-sized planet in that particular solar system.

There is a much better and simpler theory of truth than Roger's. It is called the correspondence theory of truth. According to that theory, an assertion is true simply if it corresponds to a factual reality. So even if the entire world thinks that a particular celebrity is dead, if I assert that this celebrity is alive and well and in Chicago, and that celebrity is alive and well in Chicago, then my statement is true; otherwise it's false. The truth or falsity of my statement in no way depends on whether it agrees or disagrees with a “network of assertions” being made across the world and the Internet.

Roger takes a weak poke at this correspondence theory of truth, claiming that it does not work well with universal statements of truth such as “matter is made up of atoms and molecules.” This is not at all correct. In this particular case, the correspondence theory of truth says that such an assertion is true if matter is actually made of atoms and molecules, and false if matter is not made up of atoms and molecules. That works just fine.

The correspondence theory of truth is a far more sensible theory of truth than the coherence theory of truth advanced by Roger. When it comes to the truth of a matter, what matters is facts, reality, and observations, not fitting in with the assumptions and taboos of revered authorities, whether academic or ecclesiastical.

Postscript: I criticize here merely one part of Mr. Newton's book, a work which makes many sound and valid points.