APS News Online November 2000 Edition


Creationism Versus Physical Science

By Stephen G. Brush


Cartoon by Paul Dlugokencky
Last year, some scientists were surprised to learn from press reports that the Kansas State Board of Education voted to remove Big Bang cosmology, as well as biological evolution, from the required public school curriculum. This should be a wake-up call to alert everyone that all of science education is threatened by the political power of Creationism, even if the latest Kansas election result leads to a reversal of the 1999 decision.

It may seem odd that religious fundamentalists would attack the Big Bang theory, since only a few years ago a number of popular books praised that theory as being favorable to religion: if scientists declared they could never know what happened before the Big Bang, this seemed to leave plenty of room for theologians to fill the gap.

But Creationists refuse to consider any metaphorical interpretation of the book of Genesis. In particular, "Young Earth Creationism" (YEC) insists that the entire universe was created only a few thousand years ago. Hence they reject not only the Big Bang theory (because it postulates an event that must have happened several billion years ago), but any geological theory like plate tectonics, which relies on a time scale of several hundred million years.

In general, the Creationists say any scientific theory that assumes the world has existed for more than about 10,000 years is "Evolution Science," and, they argue, should either be excluded from the science curriculum or "balanced" by the alternative "Creation Science" doctrine. Since the typical general science course offered in secondary schools contains a substantial amount of astronomy and geology, complying with that demand would have a major impact on such courses, as well as on the standard biology course.

The Creationists have learned that they cannot accomplish their objectives directly through state laws banning the teaching of evolution or requiring "equal time" for Creationism. Instead, they now try to remove evolution from the official curriculum on which statewide tests are based; even if that topic is not actually banned, teachers will not spend much time on a subject that is not going to be on the test.

Another effect of the Creationist assault on science education is a threat to the supply of qualified science teachers. There is already a nationwide shortage of high school physical science and mathematics teachers. In smaller high schools, a teacher whose degree is in biology will sometimes also be assigned to the chemistry or physics course. Political pressure to abandon the teaching of evolution is one more factor that discourages good people from pursuing a teaching career.

Physicists should also be concerned about the Creationist claim that Darwinian evolution violates the Second Law of Thermodynamics. It turns out that their version of the Second Law is different from the one taught in thermodynamics courses: it simply asserts that entropy can never decrease. The usual response is to insist that entropy can decrease in an "open system" such as the Earth, as long as it interacts with another open system, such as the Sun, in which there is a compensating increase.

A better response is to point out that the equilibrium state of a system is determined by seeking not the maximum entropy but the minimum free energy, which balances energy against entropy (E-TS). An obvious example is the crystallization of water molecules from a vapor: at low temperatures a low-energy state with low entropy (a crystal) will be favored over a high-energy state with high entropy (a gas). The Creationist version of thermodynamics fails to explain why it snows. As Ludwig Boltzmann noted more than a century ago, thermodynamics correctly interpreted does not just allow Darwinian evolution, it favors it.

In an attempt to justify their rejection of the well-established multi-billion-year time scale for the Earth's history, YEC argues that the decay rates of the radioactive isotopes used to date rocks could have been much greater under extreme conditions in the past, so the rocks are "really" much younger than they seem to be. There is no legitimate evidence for this claim from experimental or theoretical physics.

One reason Creationists want students to accept a Young Earth is to persuade them that there has not been enough time for evolution to produce humans and other modern species by the slow process of Darwinian natural selection. They are willing to reject the foundations of modern geology and nuclear physics in order to get rid of biological evolution.

The justification for rejecting the multi-billion-year astronomical time scale, on which the Big Bang theory depends, is even more remarkable. In response to the objection that many stars visible to us must have existed millions of years ago, since they are millions of light years away, YEC claims that God created the light from those stars en route to us in space, to make it look like it came from actual stars, but that no such stars ever existed.

Some Creationists find that kind of argument a little hard to swallow. In recent years another version of Creationism has come into prominence, called Intelligent Design Creationism (IDC). Its leaders sound more reasonable and some have solid academic credentials: Phillip Johnson is a professor of law at the University of California, Berkeley, and Michael Behe is a biochemist at Lehigh University. They do not necessarily deny that evolution has occurred, but they argue that Darwinian theory cannot adequately explain it. IDC generally refrains from direct attacks on physical science, while trying to hijack some of its ideas, such as the Anthropic Cosmological Principle, to support the theory that the universe has been designed to allow the evolution of life. But the IDC advocates concentrate on trying to show that Darwinian natural selection is bad, because it is materialistic (i.e., it denies any role to supernatural or spiritual causes), and because it allegedly fails to explain all biological facts. I describe IDC as "soft" Creationism because it makes no testable statements, in contrast to YEC, which makes many testable statements, all of which have been tested and refuted.

IDC relies on a logical fallacy: if Darwinian evolutionary theory fails to explain a fact, then that fact is evidence for design. But it is well known to scientists that no theory (with the possible exception of quantum electrodynamics) explains all the facts in its domain; one has to pick the best working hypothesis and try to refute or improve it. Evidence against Theory A is not evidence for Theory B, unless there are no other possible theories; but there are already many anti-Darwinian theories competing with each other.

Advocates of IDC sometimes try to distance themselves from the pro-religious, anti-science views of other Creationists. For example, after the Kansas decision, Behe wrote an op-ed piece in The New York Times (13 August 1999) saying that rather than being banned, Darwinian evolution should be taught in public schools so it could be refuted. But whatever their motives, there is evidence that they are being used by other Creationists as a respectable front or "wedge" to undermine public support for teaching evolution. If that ploy is successful, it is sure to have dire consequences for all of science education.

Both YEC and IDC, along with the late 20th century postmodern skepticism about the universal validity of scientific knowledge, undermine public support for science. We need to understand why a substantial number of citizens - not just hard core religious fanatics - reject or doubt certain basic theories of modern science, if we hope to defend science education from such attacks in the future. A major reason seems to be "guilt by association": according to the televangelists, evolution is allied with secular humanism, which is blamed for abortion, pornography, drugs, homosexuality and crime in the streets. If you teach children they are descended from animals, the reasoning goes, they will assume they can behave like animals.

More thoughtful critics object that in presenting subjects like evolution and cosmology, there is a disturbing tendency for science teachers to treat speculative or unproved theories as fact. Moreover, some physical scientists and engineers do not accept that theories in biology have the same status as those in their own field, because biological theories are not subject to rigorous tests. In particular, the evolutionary explanations given in popular books have often seemed to be no more than plausible but untestable "just so" stories. Even in cosmology, theories like the Big Bang have been presented to students and to the public as established fact, rather than as simply the best working hypothesis, still subject to modification. Finally, physical laws and theories are sometimes taught as if they provide a complete explanation for everything worth knowing, including human nature and spirituality. I am not saying that these criticisms justify interference with science education, rather that scientists should be aware of them when they address the public.

Several of the mainstream churches have rejected the Creationist position that the credibility of the Bible depends upon the truth or falsity of a particular scientific theory, and actively opposed attempts to force YEC into schools in Arkansas and Louisiana. Scientists themselves, many of whom perceive no conflict between evolution and their own religious beliefs, will have to become more politically active, including running for election to school boards themselves, or at least learning how to lobby those boards effectively. The stakes are high.

Stephen G. Brush is a professor of the history of science at the University of Maryland, College Park. He is also co-author (with Gerald Holton) of Physics, the Human Adventure: From Copernicus to Einstein and Beyond, to be published in 2001 by Rutgers University Press.



Copyright 2000, The American Physical Society.
The APS encourages the redistribution of the materials included in this newsletter provided that attribution to the source is noted and the materials are not truncated or changed.