(Left: Anti-evolutionists like to argue that belief in evolution does not derive from considering the scientific data, but from arbitrarily choosing a "starting point" of human reason over God's Word.)
A common argument against evolution as science is that science can study only present-day processes. Claims about what happened in the past are just conjecture, since we were not there and thus cannot confirm that processes of the past were the same as those in the present. By restricting the focus of science in this way, the methodology of the historical sciences is supposedly undermined.
Henry Morris, in his classic Scientific Creationism, put it like this:
The essence of the scientific method is experimental observation and repeatability. A scientific investigator, be he ever so resourceful and brilliant, can neither observe nor repeat origins! This means that, though it is important to have a philosophy of origins, it can only be achieved by faith, not by sight.
From this subtly misleading definition of science Morris then infers: “it is impossible to prove scientifically any particular concept of origins to be true.”
This limitation, argued Morris, is fundamental to science: Morris wrote these words decades ago and, despite a rather thorough refutation by philosophers of science, his claims are still being repeated. In a recent blog post Ken Ham repeats Morris’s statement from several decades ago:
Now it is true that those scientists who believe in evolution discuss and research such things as natural selection, speciation, mutations, genetics, and so on—but such things involve observational science that all scientists (including evolutionists and creationists) can deal with. However, when evolutionists use what they observe in the present (such as speciation) to extrapolate these observations in an attempt to explain molecules to man evolution, they are in the realm of belief.
The study of present-day processes is sometimes called operations science—that is, it asks how the world operates now—while the study of past process is called origins science, which wonders how the world operates in the past.
The anti-evolutionists need to split off the study of origins from the larger scientific enterprise to make their arguments work.
If, as Ham suggests, evolution is in “the realm of belief,” then he can argue that ideas about origins are all based on assumptions. In fact, this is the predominant strategy employed in the literature of Answers in Genesis and in the Creation Museum. One large display in the Museum proclaims that there are “different views for different starting points.”
The argument is developed that evolution is not based on careful science but follows from a particular starting point embraced for personal reasons, such as rejection of God or the enthronement of human reason.
This is the reason, says Ham, why “creationists and evolutionists develop totally different reconstructions of history.” Their “different conclusions about origins arise from different starting assumptions, not the research methods themselves.” And, since the “starting assumptions” are not scientific, the final conclusion is not either.
The distinction that Ham and the anti-evolutionists demand between the past and the present, however, does not exist. The study of present-day processes fades smoothly into the study of past processes with no sudden or even gradual break to distinguish operations science from origins science.
Take astronomy and cosmology for example. As I write these words the sun is coming up. Or I think it is. It takes eight minutes for the light to reach me so that regular event called “sunrise” is actually in the past. A few hours earlier the stars were out. The light from the closest stars—a group called proxima centauri— took four years to reach earth. When we look at these stars we see them as they looked before the Great Recession—seemingly oblivious to the impending financial catastrophe. The light from the stars in the Hyades cluster began its journey toward earth centuries ago, at roughly the same time that Captain Cook was heading off on his great voyage.
Because there are so many stars, we can find them at almost any distance we want. No change of any sort indicates that we have suddenly—or even gradually—entered a realm where “assumptions” have taken over. This simple fact obliterates arguments that the universe is a few thousand years old because that “model” requires that there be something different going on to explain how light can have been traveling in the universe for millions and even billions of years. Unless a real distinction can be found between operations and origins science when it comes to stars, there is simply no way to make sense of all this.
Practicing scientists in almost every discipline work with assumptions. But an assumption is not, as Ham implies, a guess based on one’s religious beliefs or lack thereof. Assumptions in science are typically positions we hold because they are so well established we don’t need to think about them any more.
We all assume the sun will come up tomorrow and plan accordingly. Chemists assume that all hydrogen atoms are identical because no evidence has ever indicated otherwise. Astronomers assume that light always travels at the same speed because every measurement indicates this. Physicists assume that radioactive decay rates are constant because they have never detected any variation.
Simple examination of the most recent past—the last few minutes—indicates that it is like the present. Ditto for last year. And, as we gradually work our way back to the distant past—a few billion years ago—we encounter no boundary where our assumption that the past is like the present needs to be re-examined.