My answer to the title question is a qualified “Yes.” A certain rare form of creationism is in principle testable and compatible with natural law, and therefore scientific, however, this is a moot point. I arrive at my conclusions purely through thought experiments. But before getting to that, let us first consider the issues of what creationism is and what it means for a theory to be scientific.
1. What is creationism?
Creationism comes in different versions but in general it is the view that the universe, life, or humanity, or any combination of these, was created by some being or beings. It is sometimes called “the theory of intelligent design.” It usually takes the form of theistic creationism, which is the view that the creator was God, as conceived by western religions. A special version of theistic creationism is biblical creationism, which maintains that God created the universe, life, and humanity as described in the Bible (that is, within a period of six days, about 6000 years ago, as may be inferred from the genealogies provided in Chapters 5 and 11 of Genesis and Chapter 3 of Luke). There are other versions of theistic creationism. Two of them are what are often called “progressive creationism” and “theistic evolutionism.”
According to progressive creationism, God created the universe, life, and humanity, but he did it over a period of time billions of years long. As various species evolved from earlier species, God intervened periodically to give the process a helping hand. Without God’s assistance, evolution would never have progressed as rapidly as it did on our planet. Theistic evolutionism is more liberal, for it maintains that God only created the universe and simple life, not any complex form of life, including humanity. The idea is that after God created a very simple life form on our planet about three billion years ago, he departed the scene and allowed evolution by means of natural selection to take over. Thus, all forms of life on our planet today, including humans, are descended (by purely natural means) from that earliest life form. A still more liberal outlook, which might be called “deistic evolutionism,” maintains that God only created the universe (about fifteen billion years ago) and nothing else. Everything other than the universe itself, including the earth and its first life form, arose by purely natural means.
There could in principle also be forms of creationism that make no reference to God or to any supernatural entities. They could be put under the heading of naturalistic creationism. The hypothetical creator(s) would need to be a being or group of beings that work completely within the natural realm and in accord with the laws of nature. Perhaps there are powerful extraterrestrials who visited earth and created things here. Since the creative activity may have been performed by a group of beings rather than a single being, they should be referred to as “the creator(s)” (with a small “c”) and the proper pronouns to use here are “they,” “them,” and “their.” Such plural pronouns would help avoid slippage of the view toward theistic creationism, which almost always employs masculine singular pronouns (sometimes capitalized). The point here is that naturalistic creationism is a quite different theory from all forms of creationism that appeal to God, and the difference needs to be continually emphasized.
Naturalistic creationism is also different from what has been called “the theory of abrupt appearance,” which has been defined as “postulating abrupt appearance in complex form” and which does not directly appeal to the idea of creation at all. Naturalistic creationism may be regarded as superior in that it attempts to provide an explanation for life or for biological change, whereas abrupt appearance theory does not. To say of something that it “appeared abruptly” is quite unclear. (It might be said, for example, of party crashers.) The concept is devoid of content in that it leaves open the possibility of creation, but is also compatible with other ideas, such as spontaneous origin out of nothing. In contrast, naturalistic creationism puts forward an explanatory concept and so deserves the label “theory.” Because of its vacuousness, so-called “abrupt appearance theory” does not deserve that label.
2. What is it for a theory to be scientific?
Theories are sets of propositions put forward to explain facts or observations. They could come to be widely known to be true and thereby become facts (or sets of facts). One example of that is the heliocentric theory of the solar system. Though not initially known to be true, several centuries ago it became a set of facts. I would say that a scientific theory is one that is capable of being produced by, or used in, science. Hence, it must be capable of employing empirical method, which relies on interpersonal observations within a framework of natural law. The main criterion for such capability is whether or not the theory is: (1) testable (i.e., test procedures that appeal to interpersonal observations can be clearly described for the theory) and (2) compatible with natural law (i.e., conforming to the known laws of nature). The theory need not be true and need not be used by current scientists, but it does need to be the kind of theory that might fit in. Scientific theories satisfy this “empirical method” criterion, as it might be called, whereas unscientific ones do not. If a theory is unscientific, it is because it is not part of an empirical pursuit of knowledge but something else, perhaps a system of thought based on revelation or authority, or something derived only from personal experiences or imagination rather than interpersonal observations.
As a paradigm example of an unscientific theory, I offer the “gremlin theory of car failure.” It maintains that the reason why some cars won’t start is that they have gremlins in them, where gremlins are by definition undetectable beings who dwell inside engines and cause them on occasion to malfunction. They do this by means of a supernatural power which also enables them to forever elude observation, no matter how sophisticated the investigator’s detection devices may be. Consider the prediction that gremlins will prevent a certain car from starting. Is this testable? I would say, “Only partly, not fully.” The prediction can be analyzed as the conjunction of these two statements:
(a) The car’s engine won’t start.
(b) The cause of that is gremlins.
Only statement (a) is testable, not (b). Since statement (a) can be falsified, the entire prediction can be falsified. But falsifiability of a prediction is not enough to make the theory on which the prediction is based testable. Since part of every prediction made by the theory is untestable, the theory itself is untestable and should not be called “scientific.” It also fails to conform to natural law, since the gremlins do things by means of forces that lie outside the known laws of nature. That would be another reason for regarding gremlin theory to be unscientific.
It has been objected that the attempt to draw a line of demarcation between scientific and unscientific theories is misguided. Two reasons are commonly given. One is that all the proposed definitions of “scientific theory” are failures because of some obscurity within them. And the other is that, even if the boundary could be clearly defined, the distinction is useless, because, whatever purpose one might try to fulfill by means of it, it would be better to try to achieve that purpose by drawing a different boundary, in particular, that between “good” theories and “bad” theories. Let us look more closely at these objections.
The first objection maintains that all the various attempts to demarcate between scientific and unscientific theories have been failures. But what is wrong with the criterion that I propose above: that a theory is scientific if and only if (1) it can be empirically tested and (2) it is compatible with natural law? It might be objected that some theories in physics do not meet requirement (1). For example, quantum theory cannot be empirically tested because it deals with entities that are in principle unobservable. My reply is that this is an overly narrow conception of testability. Quantum theory does generate empirically testable predictions and that should suffice to satisfy requirement (1). The details of this issue lie beyond the scope of the present essay. It should be noted, though, that the testability requirement is a fairly standard one and is used by scientists themselves, as well as philosophers of science.
The second objection maintains that even if a clear line of demarcation can be drawn between scientific and unscientific theories, it is not required for any useful purpose. Why draw the distinction at all? One reason is pedagogical. Schools need to decide what to teach under the heading of “science” and what to exclude. A related reason pertains to publications and libraries. Editors and librarians need to decide which manuscripts and essays are “scientific” and which books belong in the “science” section. Still another reason has to do with funding. Agencies like the National Science Foundation need to decide whether or not a proposed research project is “scientific” or not. There are many such purposes served by the given line of demarcation. The objection being considered is that instead of distinguishing “scientific” from “unscientific” theories, it would be more appropriate to distinguish “good” theories from “bad” theories. Thus, the reason why gremlin theory should not be taught in schools, or funded, or published, or given library space, is not because it is “unscientific” but because it is a “bad” theory. My reply is, first, that the line of demarcation between “good” and “bad” theories is not any clearer or easier to draw than that between “scientific” and “unscientific.” And second, there is still a need for the scientific-vs.-unscientific distinction within our present institutions. Libraries and schools, for example, will always have “science” sections and “science” classes, and not “good theory” sections or “good theory” classes. So, the suggested shift in focus is simply impractical, given the organizational structures within our present institutions. For these reasons I find the objection to be a failure.
I shall proceed on the assumption that a line of demarcation between scientific and unscientific theories can be drawn, somewhat along the lines suggested above, and that the standard objections to such an approach to our topic can all be satisfactorily rebuffed.
3. Can creationism be scientific?
We are now in a position to answer our title question. The criterion of scientificness outlined above requires that the theory be: (1) testable and (2) compatible with natural law. I see no way for theistic creationism to satisfy both parts of that criterion, although, possibly, it might satisfy the first part. Let us consider the two parts separately. First, many people take God to be a spirit that transcends space and time. That appears to place God in the same category with gremlins, so far as interpersonal observation is concerned. There is no possible way to perceive a spirit or anything that transcends space and time or anything that is eternal, omnipresent, or all-powerful, all of which are properties commonly ascribed to God. No empirical test procedures for any of those properties can be described, so when God is conceived in the given way, the God Hypothesis would be clearly untestable. I would grant, however, that there may be other concepts of God which do not assign such divine attributes, and in the case of those other concepts, the God Hypothesis might meet the testability requirement. I shall not pursue that possibility in this essay.
Second, God is supposed to be able to perform miracles. But miracles, by definition, are not compatible with natural law. They are supposed to be forever unexplainable in terms of natural causes. How, then, could such events fit in with the work of scientists? In all that they do, scientists assume that the laws of nature hold. Suppose an unusual event were to happen. How could a scientist ever ascertain that it is permanently beyond naturalistic explanation (or that it is produced by a supernatural power)? There seems to be no way to apply empirical method to miracles or the supernatural, or to fit them into what scientists do, and so they are necessarily outside the domain of science. It follows that the concept of God must also lie outside science, since that concept is essentially connected with miracles and the supernatural. Although there may be versions of the God Hypothesis which meet our first requirement (testability), there are none which meet our second requirement (compatibility with natural law). For that reason, no form of theistic creationism could be properly regarded to be a scientific theory.
There have been attempts to connect God with natural events such as the “big bang” or the origin of the first life form, but they are all failures. It adds nothing to our understanding of the world to say, “God did it,” for we have no clear idea what God is or how God is supposed to do anything, except that, however he does things, it does not conform to known laws of nature. A special problem is introduced if God is defined as either a perfect being or a transcendent being, for then it would be a contradiction to say of God that he performed an action within space and time. Perfect beings (who lack nothing) can have no motive to do anything whatever, and transcendent beings are not present in space or time to perform any spatio-temporal action. In any case, God, by definition, is supernatural, and the supernatural, by definition, is beyond empirical method and scientific understanding. Hence, all the suggestions to the effect that science has come up with evidence for the existence of God are totally misguided.
However, in answer to the title question, I would say, “Yes, creationism can be a scientific theory,” because naturalistic creationism (in sharp contrast with theistic creationism) would be scientific if it were ever to be pursued by empirical method. That is not anything that has ever been done, but it is at least possible. The main point here is that there isn’t anything within the idea of “creation” that precludes scientific investigation. The reason why theistic creationism is unscientific has to do with its being theistic, not with its appeal to the idea of creation. Psychology, for example, could study creativity within humans and other species. Thus, the idea of an “act of creation” is perfectly compatible with science.
Since naturalistic creationism does not appeal to anything outside the bounds of science, it could, under certain conditions, be a scientific theory. Suppose, for example, that aliens from outer space were to reveal themselves to us and show us how they performed acts of creation on the planet earth in the distant past. Such events could even make the theory of naturalistic progressive creationism highly probable. (But note that it is not anything that a supernatural being could do, for we could not comprehend the idea of the supernatural, except merely as something mysterious and forever unexplainable.) Once the aliens reveal their techniques to us, we could pursue empirical method in recording our observations, formulating hypotheses around them, and coming up with testable predictions based on laws of nature. Facts about biology could be explained by appeal to the newly formulated hypotheses. We would then be doing science that revolves around the theory of naturalistic creationism.
The question arises whether there would be any way to pursue naturalistic creationism as a science in the absence of special revelations from the creator(s). Could anyone do it as things stand now? Presumably not. But if not, i.e., if the hypothesized creator(s) remain hidden, then what would be the difference between them and the gremlins referred to earlier? Wouldn’t naturalistic creationism be just as unscientific as the gremlin theory of car failure? I think there would still be certain differences in principle. The creator(s) would be natural, not supernatural. Unlike the case of the gremlins, we could understand the idea of the creator(s) appearing to us and providing us with new data around which naturalistic creationism might be pursued as a scientific theory. So, from a purely conceptual viewpoint, naturalistic creationism would be potentially scientific, whereas gremlin theory would not be.
It might be objected that this distinction is just armchair philosophy and has no relevance to actual science or the teaching of science. And that is something with which I would agree. From the premise that naturalistic creationism is a potentially scientific theory it does not follow that it should be discussed in science classes. I shall elaborate on that point in the following two sections.
4. Naturalistic creationism vs. the theory of evolution
Although unscientific theories such as theistic creationism cannot be assessed by the criteria of science, naturalistic creationism can be. The most important criterion is that of explanatory power. That has to do with how well the theory explains the various facts and phenomena that need to be explained. When we examine the facts, we seem to find that they are much better explained by the theory of evolution than they are by naturalistic creationism. Consider some examples.
Why are there so many species of plants and animals in the world? The number is in the millions. The theory of evolution explains this by appeal to the processes of mutation and natural selection. Mutations occur haphazardly, producing millions of different varieties. And organisms evolve to suit their environments. Since there are so many different sorts of environments and so many different forms that are suitable for each environment, that allows for millions of different mutations to survive and thrive. In contrast, naturalistic creationism cannot satisfactorily answer the question. Why should the creator(s) want to create so many different species? The theory can only say that they had some motive for it, but we do not know what that motive was. This is nothing more than an appeal to “mystery” and cannot be regarded as a satisfactory explanation.
Why are the species of the world, including those known to be extinct, capable of being arranged in a simple-to-complex spectrum, with no very huge gaps therein? In other words, given that there are millions of different species, why do they range from the very simple to the very complex? Why aren’t they all on pretty much the same level of complexity? The theory of evolution explains this by appeal to the idea that, as evolution (descent with modification) occurred through millions of centuries, new species became gradually more complex, this being a consequence of the natural selection process itself. Thus, the most complex species on earth are relatively recent, and the simpler forms have been here for a longer time. The only way that naturalistic creationism can explain the simple-to-complex spectrum of species is by saying that the creator(s) had some motive for creating species in that way, but we do not know what that motive was. Again, this is just an appeal to “mystery” and does not satisfactorily explain the facts that need to be explained.
Why are the earliest fossils of simpler organisms (such as insects) found only in older rocks, whereas the earliest fossils of more complex organisms (such as mammals) are found in relatively younger rocks? And why is there a time-spectrum ranging from the earliest fossils of simpler organisms to the earliest fossils of more complex organisms, with no very huge gaps therein? It is obvious how this can be explained by the theory of evolution. But, again, naturalistic creationism has no explanation other than to appeal to mysterious motives on the part of the creator(s).
Why is it that geographically isolated organisms, such as on distant islands, always (in thousands of separate cases) differ radically from those of related species found on the mainland or anywhere else in the world? The theory of evolution can explain this easily. As the islands gradually drifted farther away from the mainland, they had less and less contact with it, until finally no further cross-breeding occurred. From then on, all the species on the island followed their own course of evolution. And since the environment was different from anywhere else and since the mutations that occurred were different from anywhere else, it was to be expected that on the island there would evolve totally unique species. When it comes to naturalistic creationism, there is, again, no satisfactory explanation for the given facts. It is ludicrous to suggest that the creator(s), for some mysterious reason, went around to hundreds of isolated regions (mostly islands) and created species totally unlike anything anywhere else. What possible motive could they have to do that? No worthwhile explanation is forthcoming.
There are thousands of other facts that can be satisfactorily explained only by the theory of evolution. This shows that it is a far better theory than naturalistic creationism, when it comes to the criterion of explanatory power. It might be objected that there is one thing the theory of evolution cannot explain and that is the origin of the universe. Whether that is so or not is a controversial matter. But even if it were true, it provides no victory for naturalistic creationism. It would make little sense to proclaim, “It was the creator(s) who created the universe,” for we still do not know what the creator(s) are or how they do anything or where they are supposed to have come from. Furthermore, they are supposed to be natural beings, so how could they have been in existence prior to the universe? It does not explain anything to appeal to a mystery. All in all, therefore, it is clear that, of the two theories, the theory of evolution is the one with the greater explanatory power.
Another criterion for evaluating competing theories is simplicity. Here again the theory of evolution is superior, for it appeals only to natural laws and processes with which we are already familiar, and which can be tested independently of the theory itself. On the other hand, naturalistic creationism appeals to something in addition to familiar natural laws and processes, namely, the creator(s) and the laws and processes employed by them. It thereby violates the Principle of Parsimony: “Do not multiply entities beyond necessity.” Other things being equal, we should always prefer the simpler explanation, which in this case is the theory of evolution.
Still another criterion for evaluating theories is fruitfulness (or fertility). This is the ability of the theory to generate further research and additional knowledge. Here again, the theory of evolution defeats naturalistic creationism, for it has opened up dozens of new fields of investigation for thousands of scientists, from paleontologists to physical anthropologists to biochemists researching the origin of life. No form of creationism has ever been anything but a complete dead-end, so far as generating further research is concerned.
Explanatory power, simplicity, and fruitfulness are the usual criteria for evaluating scientific explanations. When the theory of evolution is compared with naturalistic creationism by those criteria, it comes out a clear winner. That in itself is a good reason for not discussing naturalistic creationism in science classes. It would be like discussing geocentrism, or flat-earth theory, both of which are rejected because of their poor showing with regard to the given criteria. Taken as science, naturalistic creationism would be very bad science, like a theory refuted long ago. There are more important things to do in science classes than to discuss bad theories.
The philosopher Larry Laudan has said:
The core issue is not whether Creationism satisfies some undemanding and highly controversial definitions of what is scientific; the real question is whether the existing evidence provides stronger arguments for evolutionary theory than for Creationism. Once that question is settled, we will know what belongs in the classroom and what does not. Debating the scientific status of Creationism … is a red herring that diverts attention away from the issues that should concern us.
Laudan is here expressing something like the second objection to demarcation criteria between scientific and unscientific theories that was discussed in section 2, above. I do not agree with him that the issue of the scientificness of creationism is a “red herring,” for, as I hope to have shown, a good case can be made for saying that theistic creationism is unscientific. If a theory is unscientific, then the very issue of its evidential support cannot be raised. Since there is no way to evidentially support such a theory, there is no way to do the thing that Laudan suggests, that is, to compare it with the theory of evolution with regard to their respective degrees of evidential support. However, I would agree with Laudan if he were merely to claim that there is in principle some form of creationism which can be compared with the theory of evolution and evaluated according to the usual criteria for scientific explanation. And I would also agree with him that such a form of creationism should not be discussed in science classrooms because of its exceedingly poor showing by such criteria.
5. The problem of “slippage”
Another reason why naturalistic creationism should not be discussed in science classes is a purely pedagogical one: such a practice would incline teachers to “slip” from naturalistic to theistic creationism. Even if they were to start out talking about “the creator(s)” (which is itself rather unlikely), it is almost certain that they would move to talking about “the creator” and then “the Creator” and finally “God.” And that would be bad. To discuss theistic creationism in a science class would be bad because it is not even a potentially scientific theory, and so it would be totally out of place in such a setting.
The above reason applies to all schools, but there is a further reason that applies specifically to public schools. It might be said that theistic creationism, especially biblical creationism, is a form of religion, so to teach it as science in the public schools would be to “establish a religion” in the state, which would be a violation of the anti-establishment clause of the First Amendment to the U.S. Constitution. The unconstitutionality of teaching theistic creationism in public-school science classes has already been determined by federal courts.
But the issue here is naturalistic creationism. Why would those who set out to discuss naturalistic creationism probably “slip” to discussing the theistic form? One reason is that naturalistic creationism is a totally unfamiliar theory, even within the context supplied by our title question. There is no mention of it within the familiar Ruse anthology entitled But Is It Science?. Nor was there any mention of it at the Symposium entitled “Can There Be a Scientific Theory of Intelligent Design?” held at a meeting of the American Scientific Affiliation in 1993. No scientist has ever formulated it, let alone pursued it. There is no one who espouses naturalistic creationism. The public has never heard of it, and if informed, the public would be appalled. People would say things like, “That is certainly not anything I want taught.” Everyone who thinks about creationism or uses the term “creationism” means by it the theistic form. In effect, creationism, in the public mind and in the mind of all creationists and anti-creationists, is theistic creationism. So even if a teacher and students were to start out discussing naturalistic creationism, it is almost certain that they would end up with the familiar theistic form.
Another reason why such “slippage” would probably occur is that everyone who wants creationism discussed in science classes has in mind the theistic (and especially the biblical) form. In other words, even if the unfamiliar naturalistic form were to become familiar, it is not what anyone wants. Hence, there would be little or no motivation on anyone’s part to either discuss naturalistic creationism or have it discussed by others.
My conclusion is that although it would be proper under certain conditions to classify naturalistic creationism as a “scientific theory” (or as a “potentially scientific theory”), that is a moot point and has no application to public policy. There are excellent reasons (of both a scientific and pedagogical sort) for teachers not to present or discuss the theory in any science class. Therefore, let our classification of creationism as “possibly scientific” remain purely a theoretical point in the philosophy of science.
 W. R. Bird, The Origin of Species Revisited: The Theories of Evolution and Abrupt Appearance, two volumes (New York: Philosophical Library, 1987). See vol. I, p. 18.
 Larry Laudan, “Science at the Bar–Causes for Concern,” Science, Technology, & Human Values 7, no. 41 (1982), pp. 18-19. Reprinted in Ruse, below, pp. 354-355.
 Michael Ruse, ed., ButIs It Science? The Philosophical Question in the Creation/EvolutionControversy (Amherst, NY: Prometheus Books, 1988).
 See the report of that symposium by Paul Nelson which appears on the Internet at: <URL:http://www.arn.org/docs/orpages/or152/152main.htm>.