NY Times, August 15, 1999, Sunday Week in Review

It's a Fact: Faith and Theory Collide Over Evolution


George Johnson

Educators and scientists may find it shocking or merely tedious that politicians are still fighting over whether evolution should be taught in school. But those who champion scientific over religious explanations might strengthen their case if they conceded a point to the opposition: Since evolution is indeed a theory and not a fact, it can be taught side by side with creationism. The result would be a wider appreciation that creationism isn't even a theory, and that what evolution's opponents consider its weakness is actually its strength: Like all of science, it is based on malleable human knowledge.

When the Kansas Board of Education voted last week to discourage the teaching of evolution and eliminate questions about the subject from student evaluation tests, the rationale was familiar. Since no one can rewind the universal clock and be present at creation, any idea about how life began is, at best, informed speculation.

Using the same reasoning, the board also cut the Big Bang, cosmology's unifying vision, from the curriculum.

The implication was that, in Kansas, students will be considered educated if they learn to accept only what is directly evident to their senses or what they trust was observed by competent witnesses -- with an exception made for what they believe because it is decreed by their particular religion. Taken to the extreme, this would eliminate not only the reigning theories of biology and cosmology but almost all of science including the atomic theory of matter and the heliocentric model of the solar system.

The skewed view of science that won over the Kansas school board is epitomized by the warning used in Alabama classrooms: "This textbook discusses evolution, a controversial theory some scientists present as a scientific explanation for the origin of living things, such as plants, animals and humans. No one was present when life first appeared on Earth. Therefore, any statement about life's origins should be considered as theory, not fact."

The first sentence is false. Most scientists, by far, accept the theory; the controversies are over details. But the second part of the warning is undeniably true, and science would benefit if it were more often presented this way.

Science consists entirely of theories -- tentative, fluid proposals based on people's best bets for how the world works. It is because they are not set in stone that these ideas have a chance of being nudged closer and closer toward describing reality, or discarded in favor of something better. Last week, two days after the Kansas school board decision, paleontologists published evidence that may push back the appearance of complex life -- single cells with nuclei -- by as much as a billion years.

Whenever setbacks like the one in Kansas occur, scientists leap forth to point out the fallacy of the creationist position: There is no compelling reason to single out the evolution of life or the cosmos as being less than absolute. It would be just as sensible for school boards to affix a warning inside physics books: "No one has directly observed the detailed substructure of matter. Therefore, any statement about it being made of atoms should be considered as theory, not fact."

The problem is that the dynamic view of science doesn't come across strongly enough in the classroom. For reasons of expediency, scientific theories are presented as done deals. Little appreciation is conveyed for the intellectual struggle that went into interpreting the data or examining the assumptions -- always open to question -- that lurk behind the experiments. Lost from most explications is the exhilarating possibility that a theory that seems undeniable today could be overturned tomorrow.

With science presented almost as though it were received wisdom, it's little wonder that some legislators and school board members confuse it with a competing religion, and misconstrue a religious belief like creationism as an alternate scientific theory.

They're encouraged to do so by a new wave of creationists who, in an act of intellectual jujitsu, promote their belief in absolute knowledge by invoking the relativistic arguments of post-modern philosophy: While creationism is built on belief in a caring, all-powerful, constantly intervening creator, who completed his work thousands of years ago, evolution has its own tenets of faith. The most fundamental is the belief that the world consists of insentient matter unfolding on its own over vast eons of time -- eons that can only be inferred from indirect evidence. One is still free to believe in a deity, but it's not a necessary part of the equations.

Among the other fundamentals of science is the doctrine of uniformity, that the physical laws are the same now as they were in the past.

And this is closely related to another unprovable assumption, Occam's razor: Given two explanations for a phenomenon, the simpler one is more likely to be true. If one chooses to reject these assumptions, then evidence taken to support evolution, like radiocarbon dating, can be rearranged to support creationism.

Viewed this way, science may seem like just another religion -- based on things one chooses to believe because they seem deep down to be true. But giving creationism equal time in the classroom would undermine the comparison.

Granted that it is possible, starting from naturalism or supernaturalism, to draw different pictures of the world, which one, the lesson plan could ask, seems more ad hoc, more a case of special pleading? Can you envision evidence that would cause science to support a much younger Earth? The answer is yes. It would take very convincing data coming from many different directions, but the mechanisms used to measure geological time are not unshakable truths.

Then the teacher could ask, Is there any conceivable experiment that would cause creationists to accept a four-billion-year-old planet or the evolution of human life from a single-celled ancestor? Maybe. But then it wouldn't be creationism anymore. For something to be called a theory, it has to be falsifiable, capable of being overthrown.

Students could also be taught the dangers that come when a scientist mistakes a theory for eternal truth, shoring up flimsy hypotheses by contorting the data. They could learn of cases in which a religion flexibly adjusted its doctrines because of new social realities, allowing, for example, homosexuals into the ministry.

But slowly, by giving creationism equal time with evolution, the class would see a powerfully subtle difference. Science is, foremost, a method of interrogating reality: proposing hypotheses that seem true and then testing them -- trying, almost perversely, to negate them, elevating only the handful that survive to the status of a theory. Creationism is a doctrine, whose adherents are interested only in seeking out data that support it.

In making sense of the world, one is always free to start from different assumptions. But part of a good education is learning what you are trading off in the bargain.