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Our future, our universe, and other weighty topics

Thursday, June 19, 2014

The Professor's Cosmic Confusions

There was an interview in the New York Times a few days ago with Tim Maudlin. The topic was the relation between religious ideas and modern cosmology. Since Maudlin is a professor of philosophy at New York University, and the author of a book on the philosophy of physics, readers might have expected some keen insights, but what they got instead was very shaky reasoning. 

Maudlin spends the first part of the interview trying to suggest that cosmology has discredited religious thinking because it shows that the universe is very big, that man is not the center of the universe, and that the universe was not created specifically for the human species. Maudlin asserts, “Theism, as religious people typically hold it, does not merely state that some entity created the universe, but that the universe was created specifically with humans in mind as the most important part of creation.“ This is what is called a straw man argument, an attempt to discredit something by presenting some ridiculous caricature of it. Not many serious astronomically-literate thinkers of the past fifty years have maintained that our vast universe was created mainly for the sake of the human species, or that man is the most important species in the universe. Theism may simply be defined as the belief that some higher power created the universe. The outdated belief that man is the most important part of the universe is an entirely separate belief that is not at all a consequence of theism. Discrediting that outdated belief does absolutely nothing to discredit theism.

The interviewer then mentions that some have argued that the universe's fundamental constants seem to be fine-tuned (as discussed here), and that may suggest that the universe was designed by some intelligence interested in having intelligent creatures exist. Here is Maudlin's reply:

Our physical theories contain quite a large number of “constants of nature,” of which we have no deeper account. There seem to be more of them than most physicists are comfortable with, and we don’t know for sure whether these “constants” are really constant rather than variable. This gives rise to questions about “fine-tuning” of these constants. One thing to keep in mind is that the true number and status of the “constants of nature” is not part of any well-established physical theory: It is part of what we don’t yet know rather than what we do know...Since we don’t even know if the “constants” are constant, we certainly don’t know enough to draw any conclusions about the best account of why they have the particular values they have right now and around here. Since we don’t know how the various “constants” might be related to each other by deeper physics, the game of trying to figure out the effect of changing just one and leaving the rest alone also is not well founded.

These statements are a combination of misinformed falsehoods and irrelevancies. Very far from being “part of what we don't yet know rather than what we do know,” the fundamental constants are some of the more well-understood aspects of nature. We pretty much know everything about them except why they have the numerical values that they have. We know the fundamental constants of nature (things such as the gravitational constant, the proton charge, the proton mass, and the speed of light) so well that we have measured their values to six decimal places or more, as shown in the table below. Maudlin's claim that the constants of nature are “not part of any well-established physical theory” is hilarious. The constants of nature are, in fact, fundamental parts of the most well-established theories in modern science: Einstein's theory of special relativity, Einstein's theory of general relativity, quantum mechanics, and the Standard Model of Physics. We also know with a very high likelihood that the constants of nature have varied by almost no amount over the course of billions of years. Studies of quasars and isotopes typically produce a result such as a variation of less than 1 part in 100,000 over a billion years. Whether they vary by a very tiny amount over billions of years is irrelevant to discussions of whether such fine-tuned constants support the idea that the universe was purposefully created.

“Trying to figure out the effect of changing just one [constant] and leaving the rest alone” is not a game, but a perfectly serious scientific task which quite a few scientists have engaged in over the past five decades, publishing their results in scientific papers (100 examples can be found here). Far from being “not well founded,” such results are numerically rigorous and as well-founded as any other scientific results. In short, almost everything Maudlin says on this topic is off-base.

Fundamental physical constants

Maudlin also reasons as follows:

One thing is for sure: If there were some deity who desired that we know of its existence, there would be simple, clear ways to convey that information. I would say that any theistic argument that starts with the constants of nature cannot end with a deity who is interested in us knowing of its existence.

This argument is irrelevant because whether a creator wants us to know of his existence is a separate issue from whether such a creator exists. It is entirely possible that there exists a creator who is not particularly interested in whether tiny small-brained bit-player creatures such as us are certain of that creator's existence at this point in our development. A theist could also argue that the creator has left signs of his work in nature (the Big Bang, the exact equality of the proton charge and electron charge, the extreme fine-tuning of the cosmological constant, the improbable smoothness of the universe, and so forth), and that the gradual unveiling of such signs over decades (with the help of science) is ultimately more uplifting than some one-shot affair of seeing something like a “God exists” sign in the sky.

Perhaps realizing that he has failed to shoot down the idea that the universe's fine-tuning may suggest a cosmic creator, Maudlin then resorts to the favorite last resort of the champions of blind chance: a theory of an infinity (or near-infinity) of other universes. When all else fails, pull a multiverse out of your hat. Maudlin concedes that “this idea is highly speculative, and there is no direct evidence in its favor. “ One might also add that postulating an infinity of universes fails from the standpoint of Occam's Razor (“entities should not be multiplied beyond necessity”), because it leads you to the most complicated explanation possible rather than the simplest explanation. Moreover, a multiverse fails as an explanation because it postulates a situation in which there may be a likelihood of some universe being habitable, but does not change the odds of our universe being habitable, which are exactly the same regardless of whether a multiverse exists. There is also the fact that while we know many things are due to coincidence and we know that many things are due to design, in the history of explanation there is not one verified case of anything being successfully explained by assuming a multiverse; so in that sense a multiverse explanation is not on solid intellectual ground. We may also wonder: if Maudlin doesn't think the fine-tuning of physical constants is such a big deal (as he suggests), then why he is going to the extreme of suggesting a vast number of universes to try to explain it?  

Discussing whether the Big Bang (the sudden origin of the universe about 13 billion years ago) may support the idea that the universe had a creator, Maudlin says, “I think we don’t know enough to make any plausible guess about even whether there was an initial state, much less what it might have been. This goes beyond what we have good evidence or theory for.” Most cosmologists would disagree with that statement. Such scientists say that we do have good evidence that the universe suddenly began about 13 billion years ago in the event called the Big Bang. The evidence includes the cosmic background radiation and the expansion of the universe (“rewinding the tape” on a universe in which galaxies are all flying farther and farther apart from each other leads inevitably to a point of sudden origin in a state of incredible density).

Schematic diagram of Big Bang and expanding universe

There is abundant evidence that something like the Big Bang was the beginning of our universe, which is why Penzias and Wilson won the Nobel Prize. There may be some small degree of uncertainty in regard to this beginning, a little wiggle room for doubt, but it is not accurate to claim as Maudlin does that “we don’t know enough to make any plausible guess about even whether there was an initial state.” We do have enough not just to make a plausible guess, but to make a high-probability conclusion: the evidence very clearly indicates us that there very probably was a sudden beginning 13 billion years ago. It also indicates that the initial physical state of the universe had "an enormous amount of fine-tuning," in the words of a recent scientific paper on the topic, discussed here.

Maudlin also states, “As yet, there is no direct experimental evidence of a deity, and in order for the postulation of a deity to play an explanatory role there would have to be a lot of detail about how it would act.” But, in fact, modern scientists do grant an explanatory role for things for which there is no direct experimental evidence, even when they don't have any details about such things or how they act. Two such things are dark matter and dark energy, both of which are completely mysterious, not understood in any detail, and not things that have been confirmed by any experiment. Scientists are willing to adopt completely vague ideas of the likely existence of dark matter and dark energy, without any details, because they find postulating such things useful in explaining certain hard-to-explain characteristics of our universe. So by requiring a “lot of detail” about an explanatory factor before making an explanatory assumption, Maudlin is setting up some artificially high hurdle for the hypothesis of a divine creator, one that scientific assumptions are not required to meet.

Postscript: A huge team of scientists (the Planck satellite team) has just released a paper finding that two of the fundamental constants of nature (the fine structure constant and the electron mass) have changed by less than 1 percent since the beginning of the universe.