This is the second installment in a series inspired by exchanges with Jerry Coyne. Readers might want to read the first in the series for orientation.
Editor's Note: The corrected version of Part II was posted on October 2.
The first straw man I want to examine is Coyne’s strong assertion that scientific ideas are empirical and testable and religious ideas are not. I would be the first to admit that this is largely true. Ideas from the hard sciences—physics, chemistry, biochemistry—are solidly empirical in ways that ideas from religion can never be. But then ideas from the hard sciences are empirical in ways that ideas from sociology and economics can never be. The degree to which a body of knowledge is empirically grounded ranges broadly as one passes from physics, thru chemistry and biology, into the social sciences.
Coyne compares the well-understood function of penicillin to belief in the incarnation of Jesus and notes that the former is well-established as true but the latter is just a matter of faith with nothing more than a “book” to suggest that it might be true. (And, of course, he notes that the “book” of the Christians is just one holy book among several, all making different claims with no clear way to adjudicate among them.) In making this comparison, Coyne is pulling a simple and strongly empirical example from one end of the spectrum and making a major point about how it differs from an idea at the other end of the spectrum.
Here is why I think this argument fits into the logical pattern of the “straw man.” The various truth claims being made by science can be arrayed along a spectrum that starts with ideas that can appropriately be labeled “established as true.” One of the great achievements of science is to establish truths with such magnificent clarity that we forget how great the achievement was in the first place. Few people are impressed any more with the way that science established the roundness of the earth, its motion around the sun, the elliptical shape of its orbit, or its great age. But these were all incredible achievements. Ditto for the periodic table of the elements, the function of DNA, and the behavior of penicillin. The scientific community is united behind these claims which can all be considered “established as true.”
But the spectrum of science is not exhausted by such straightforward claims about the world. Nor were these ideas always so well-established and unambiguous. The initial proposals that the earth moved about the sun were rejected by scientists in the 17th century—called natural philosophers in those days—in large part because there was no empirical evidence that the earth was moving. It is a myth—a straw man myth—that the objections were based entirely on the Bible. The arguments for the motion of the earth were not strongly empirical and it would be two centuries until empirical evidence was forthcoming. But the motion of the earth became widely accepted despite the absence of empirical evidence, not because of it. The reasons had to do with the “elegance” of heliocentricity and the “mathematical simplicity” of sun-centered models of the solar system.
In much the same way today we have an animated discussion about multiple universes. Many leading scientists believe in multiple universes. But no empirical evidence of any sort exists for these universes. None. The reasons to believe in multiple universes have to do with abstract mathematical arguments. Cosmologists have “equations of the universe” they solve that have more than one solution. Some of the equations appear to have an infinity of solutions. And one of the solutions is a mathematical description that looks like something that resembles our universe. But what is the status of all these other solutions? Can we say that other universes exist just because they are “allowed” by the mathematics?
Mathematics relates to the world in very complicated ways. The typical equation of mathematical physics will have more than one solution and physics students are taught to compare all the solutions to the real world and “throw away” those that don’t match. A trivial example of this would be an equation for the length of the side of a square with an area of 4. The length of the side will be the square root of “4,” which has the value “2.” But “-2” is also a square root of 4. (-2 times -2 equals 4). So what do we do with this other solution that makes no sense? We throw it away because it doesn’t correspond to any real squares.
We know from experience that the there are more “mathematically allowed” realities than there are actual realities. Mathematics allows us to have squares with sides of negative length. But such squares don’t exist in the actual world, as near as we can tell.
There is an amazing story though, about such square roots. The great mathematician Paul Dirac was once working with a square root dealing with Einstein’s theory of relativity. The square root had the famous solution E = mc2. But there was a second solution that Dirac’s peers had been simply throwing away, as they had been trained to do. Dirac had a heightened confidence in the ability of math to describe the real world and he decided that the “wrong” solution should not be thrown away, and he set about trying to figure out what it could mean. After some frustration, he decided that it might be “anti-matter,” for which there was no evidence. But, as we know, anti-matter turned out to be very real.
The status of mathematically suggested alternate realities is quite mysterious.
Such examples could be multiplied endlessly. What we know from experience is that the solutions to our equations often tell us things about the real world that we did not know. But they often tell us nothing, and we simply throw them away as meaningless collateral.
This is the situation with the multi-verse today. We have equations with solutions that may or may not describe a reality for which at present there is not a shred of evidence. This uncertainty may resolve itself or it may not. Leading scientists may continue to dispute whether our universe is unique, or one of many, or one of an infinity.
The straw man argument comes into play when we take the simplest settled truths of the hard sciences and contrast them with the ambiguous and unsettled “truths” of other fields, or the less settled claims of the hard sciences, or the claims of fields for which “settled truths” would not be expected. Science itself has many ambiguous and unsettled “truths.” This is not to say that religious truths are thus now on the same playing field with scientific truths. Science purchases its great success by choosing easy problems and thus will always provide a clearer model for thinking than, say theology, or literary criticism, or sociology, or aesthetics. And religious claims, being predominantly moral and metaphysical, are fundamentally different to begin with.
Exclaiming about how much clearer our understanding of penicillin is than our understanding of the Incarnation is nothing more than a statement that truth claims lie along a spectrum. Claiming that this is an argument that invalidates religion goes way too far.