[Second revision (May, 1997) of the paper originally presented at the Conference on Naturalism, Theism and the Scientific Enterprise, sponsered by the Department of Philosophy, The University of Texas, Austin, Texas, February 20-23, 1997. A further Web revision will appear soon. This paper will ultimately be revised and submitted for publication in a philosophical journal. You may link to this page, but please do not quote this unpublished version without permission. Thank you.]
Verachte nur Vernunft und Wissenschaft,
des Menschen allerhöchste Kraft,
laß nur in Blend- und Zauberwerken
dich von dem Lügengeist bestärken,
so hab' ich dich schon unbedingt.
Mephistopheles in Goethe's Faust 
Naturalism is, ironically, a controversial philosophy. Our modern civilization depends totally for its existence and future survival on the methods and fruits of science, naturalism is the philosophy that science created and that science now follows with such success, yet the great majority of humans (at least 90% of the U.S. population) believe in the antithesis of naturalism--supernaturalism. Our culture persistently indulges and celebrates supernaturalism, and most people, including some scientists, refuse to systematically understand naturalism and its consequences. This paper proposes to show that naturalism is essential to the success of scientific understanding, and it examines and criticizes the claims of pseudoscientists and theistic philosophers that science should employ supernatural explanations as part of its normal practice. Along the way I will speculate briefly on the reasons why such individuals are today advocating what would appear to be such an oxymoronic conjunction as supernaturalistic science (or worse, theistic science). Also, quite a bit of this essay is devoted to examining basic concepts in metaphysics and the philosophy of science, since there seems to be some confusion about them.
"a species of philosophical monism according to which whatever exists or happens is natural in the sense of being susceptible to explanation through methods which, although paradigmatically exemplified in the natural sciences, are continuous from domain to domain of objects and events...[thus, there cannot] exist any entities or events which lie, in principle, beyond the scope of scientific explanation" (Danto, 1967, p. 448);
"the view that nature is all there is and all basic truths are truths of nature" (Audi, 1996, p. 372);
"the twofold view that (1) everything is composed of natural entities--those studied in the sciences--whose properties determine all the properties of things, persons included, ...abstract entities... like possibilities...and mathematical objects...and (2) acceptable methods of justification and explanation are commensurable, in some sense, with those in science" (Post, 1995, p. 517);
"the view that everything is natural, i.e. that everything there is belongs to the world of nature, and so can be studied by the methods appropriate for studying that world..." (Lacey, 1995, p. 604);
"the philosophical movement that "wishes to use the methods of science, evidence, and reason to understand nature and the place of human species within it"..."skeptical of the postulation of a transcendental realm beyond nature, or of the claim that nature can be understood without using the methods of reason and evidence"... and "the philosophical generalization of the methods and conclusions of the sciences" (Kurtz, 1990, p. 7, 12).
In my own definition, a synthesis of those above, naturalism is the philosophy that maintains that (1) nature is all there is and whatever exists or happens is natural; (2) nature (the universe or cosmos) consists only of natural elements, that is, of spatiotemporal material elements--matter and energy--and non-material elements--mind, ideas, values, logical relationships, etc.--that are either associated with the human brain or exist independently of the brain and are therefore somehow immanent in the structure of the universe; (3) nature works by natural processes that follow natural laws and can, in principle, be explained and understood by science and philosophy; and (4) the supernatural does not exist, i.e., only nature is real, therefore, supernature is non-real. Naturalism is therefore a metaphysical philosophy opposed primarily by supernaturalism.
Naturalism is, noncontroversally, a subset of metaphysical realism. Naturalism is not an ethical system, although a variety--pragmatic naturalism, a synthesis of pragmatism and naturalism--does develop ethical positions. Philosophical naturalism is also the key part of naturalistic humanism, without question the most important personal worldview or philosophy of life that exists as an alternative to the planet's many supernaturalistic, transcendental religions and religious philosophies. Humanism exists in two varieties, religious and secular, and as a dynamic, fulfilling, and intellectually compelling alternative to transcendental religion, humanism is a frequent subject of criticism by supernaturalists; indeed, part of the motivation for the attack on naturalism in science by creationists and intelligent design proponents is their explicit and long-founded antipathy to naturalistic humanism. Philosophical naturalism itself exists in two forms: (1) ontological or metaphysical naturalism and (2) methodological naturalism. The former is philosophical naturalism as described above; the latter is the adoption or assumption of philosophical naturalism within scientific method with or without fully accepting or believing it. As will be exhaustively discussed below, science is not metaphysical and does not depend on the ultimate truth of any metaphysics for its success (although science does have metaphysical implications), but methodological naturalism must be adopted as a strategy or working hypothesis for science to succeed. We may therefore be agnostic about the ultimate truth of naturalism, but must nevertheless adopt it and investigate nature as if nature is all that there is. This is methodological naturalism.
Is naturalism true? We may think so, but we can't know for certain. Naturalism's truth would presumably depend on the existence of a supernatural realm. If there were empirical evidence for the supernatural or a logical reason to believe in the supernatural without such evidence, then naturalism would be false. If we knew for certain that the supernatural did not exist, then naturalism would be true. But if there is no evidence for the supernatural and no reason to believe in it despite the lack of evidence (both of which are the case), the supernatural could still possibly exist without our knowledge. Such a lack of evidence and reason forces one to be agnostic about the existence of the supernatural and thus about the ultimate truth of naturalism. However, because of such lack of evidence and logical argument, it is more reasonable to disbelieve the supernatural and believe that naturalism is true.
Fortunately, whatever we think about the supernatural, we may all agree that a natural world exists. Naturalism could be accepted as the most reasonably true philosophy by examining and justifying it's statements as a scientist would examine and justify the statements of a scientific theory. In scientific terms, the truth of naturalism could be considered reliable knowledge, since naturalism's statements have a great amount of empirical evidence in support of them, it has a highly-reasoned logical structure, and the statements of this logical structure have been repeatedly and skeptically tested and corroborated. Such a truth, however, as with all such scientific truths, must be held skeptically and tentatively, since it is only reliable knowledge, not absolute, ultimate truth (whatever that is). This idea of demonstrating the truth of a philosophy by the same means one would use in the scientific method to investigate natural elements (examining empirical evidence, using logical reasoning, skeptically testing one's claims to achieve corroboration, etc.) seems reasonable to me, but it may not seem so to more knowledgeable philosophers. But I have no better justification for naturalism's truth than this scientific one.
Even though naturalism has two primary sources in philosophy, "materialism in metaphysics and empiricism [and skepticism] in epistemology" (Kurtz, 1990, p. 12), naturalism does not necessitate a commitment to materialism, a philosophy with which it is often confused (more on this below). Materialism recognizes the existence of non-material elements, but claims that they are unconditionally produced by or associated with material elements, that is, the non-material elements would not exist if the material elements did not exist. Certainly most philosophical naturalists today are materialists, and methodological materialism is probably universally adopted among scientists today, but idealism or dualism could be true and naturalism would still be viable. Some of the early logical positivists were phenomenalists (phenomenology is a type of idealism). Furthermore, non-material elements (such as the conscious mind) undoubtedly exist, and their relation to or association with the material world (such as the brain) is still problematical and a concern of both scientific investigation and philosophical analysis (e.g., Dennett, 1991, 1996). I reference Daniel Dennett, a noted philosopher, to show that the overwhelming belief among scientists that mind is a function of matter, the brain, is still legitimately the subject of philosophic analysis, even though Dennett uses our scientific knowledge of brain and consciousness to ultimately defend an entirely naturalistic and materialistic interpretation. The point is that although we believe that materialism is true, it is still a metaphysics like naturalism, and its truth or untruth does not affect the standing of naturalism or our belief in it veracity.
The above authors and I would agree, therefore, that naturalism is much broader in scope than materialism, and it could entertain a wide diversity of metaphysical positions, such as idealism or materialism, monism or dualism, atheism, and even theism, since a natural deity or god could be conceived as one immanent in the universe (pantheism) or contained in the self. Idealism, dualism, and theism are therefore legitimate stances within naturalism but, for a number of reasons, are not very popular among naturalists. Individuals who would normally believe such things are usually already supernaturalists, and so don't care about these tiny subcategories of naturalism. Metaphysics in this context is important, and I reject the positivist idea that metaphysics is cognitively meaningless and that science alone provides genuine knowledge, since I believe that science itself is based on a number of highly-developed philosophies (epistemologies), as explained below.
Supernaturalism, the antithesis of naturalism, includes belief in supernatural beings (gods, goddesses, lesser deities, angels, devils, fairies, trolls, leprechauns, ghosts, wood nymphs, etc.), their activities (miracles, raising from the dead, faith healing, virgin birth, life after death, communication between living and dead, communication between human and god, ritual symbolic cannibalism of the avatar, etc.), their realms (heaven, hell, spirit worlds, etc.), and their concerns (transcendence, sanctification, salvation, sin, immortal souls, spirits, etc.)--in short, as many would claim, belief in superstition from the highest to the lowest. Since everyone agrees that the natural exists, it is the responsibility of the supernaturalists to demonstrate the existence of the supernatural. This they have not done.
Although some may disagree with me about this, it is obvious that there is no empirical evidence for supernatural elements and no reason to believe in them despite the lack of evidence, but their overwhelming popularity makes naturalism a distinctly minority philosophy among popular philosophies today, especially in the United States. Belief by wishful, hopeful, and emotional faith, and by authoritarian admonition, are the most common ways belief in the supernatural is promoted and justified, but that is not our issue here. We are concerned with the relationship of science and naturalism, whether science assumes or necessitates methodological or ontological naturalism or both, and whether supernaturalism can or should be a part of science.
What is Science?
Science is a truth-seeking, problem-solving, method of inquiry. The reliability of its scientific method depends on the correctness of three ancient philosophies that science uses: empiricism, rationalism, and skepticism. This strange combination of epistemologies--for historically they were at odds with each other, and in extreme form remain so today--was used and molded by scientists through the centuries to construct modern science. Empirical evidence is used to propose hypotheses which logically explain natural causes by predicting natural effects; because explanations might be fallacious, hypotheses are skeptically tested by additional empirical observations or experiments to see if their predictions are fulfilled; if so, the corroborated hypotheses are used to construct logical theories that explain the universe. This one sentence describes a method so powerful that it has profoundly and irrevocably changed human society, culture, and philosophy.
I can't defend the truth of these three philosophies here, and perhaps I don't need to, but I do acknowledge that these three epistemologies are logically and methodologically prior to science, although I believe that scientists (including "natural philosophers") were the individuals first responsible for rigorously practicing them, demonstrating their truth, and in some cases (e.g., Aristotle), first analyzing and explaining them. Today these three epistemologies are taught in schools as "critical thinking," a methodology indistinguishable, in my opinion, from scientific thinking. This point cannot be made too strongly. Paul Kurtz (1990, p. 7) states, for example, that "Science is not interpreted as an esoteric method of inquiry, but is continuous with standards of critical intelligence used in common, ordinary life." I have long told students--as a justification for university science requirements--that when they learn scientific thinking in their science courses, they will in addition learn critical thinking, the best and most reliable type of thinking, that will enable them to successfully solve problems and answer questions throughout their lives. I am not aware how grateful they are for this justification, but it's convincing to me.
Science uses critical thinking to discover new and reliable knowledge about nature, but critical thinking can be used in all other aspects of life as well. Critical thinking has been epitomized as "the scientific method" in science, simply because scientists must practice it to be successful, so it is in science that critical thinking finds its most thorough-going and rigorous praxis. But critical thinking is also used in business, government, jurisprudence, the arts, the humanities, the social sciences, and especially philosophy. Natural science has no monopoly on critical inquiry or reliable knowledge, or on the empiricism, rationalism, and skepticism that underlie them. Science is undoubtedly the most visible and systematic practitioner of critical inquiry, since its use in the other disciplines is less pervasive (although highly valued by some in the social sciences and the humanities). Indeed, non-critical types of thinking--authoritarian, dogmatic, canonical, emotional, wishful, hopeful, subjective, biased, persuasive thinking--are often just as popular and successful as critical thinking in non-science disciplines, so critical inquiry is sometimes not valued as highly as it is in science. My major point, however, is that critical inquiry is humanity's surest path to reliable knowledge in all areas of inquiry, not just in science.
The principles of critical inquiry or scientific thinking are straightforward: when dealing with the natural world--that is, the universe--truth claims require empirical evidence and logical arguments to support and legitimatize them. You now have hypothetical knowledge, but that is not good enough, because you are still skeptical of the results. So you test your hypotheses, and when corroborated, you now possess reliable knowledge, which is as close as humans can get to the truth in a natural world, but it is close enough. Later in this paper, I will demonstrate that naturalism is a methodological necessity in the practice of science by scientists, and an ontological necessity for understanding and justifying science by scientists. But I can discuss the general justification for the essentiality of naturalism in science now. The alternative to naturalism is supernaturalism, and unless naturalism is true and supernaturalism false, empiricism--comprehending reality solely by sensory experience--is not sufficient to comprehend reality; rationalism--the use of logic in reasoning--is not sufficient to understand reality; and skepticism--the questioning and evaluation of one's knowledge system and beliefs--is not sufficient to arrive at reliable knowledge of reality. Simply put, empiricism, rationalism, and skepticism--the foundations of science--will not be epistemologically reliable unless naturalism is either true or assumed to be true, since by not doing so, part of reality will remain unexplained and unexplainable.
Naturalism implies a unity and lawfulness in nature, a condition in which nature's reality can be objectively understood, without which the pursuit of scientific knowledge would be useless and uncertain. If supernaturalism were true, miracles would allow unique, non-repeating, and non-controllable events to cause natural effects that would be incomprehensible using empirical methods of investigation. Omnipotent deities could act arbitrarily and irrationally without compunction and violate natural laws for no humanly-comprehensible reason. No acceptable criteria exist or can exist for establishing the validity of supernatural events, so any example of supernaturalism is meaningless as a form of knowledge. Supernaturalism, therefore, makes a mockery of skepticism, since in a supernatural world everything imaginable is possible. If everything imaginable is possible, then skepticism is unnecessary and meaningless. The meaninglessness of skepticism is possibly the greatest objection of naturalists to supernaturalism, because a supernatural world allows everything and anything to be possible, so all beliefs about things are therefore permissible and thus all actions that follow from those beliefs are permissible and morally defensible (postmodernism would actually be true in a world where the supernatural was real!). Even a casual acquaintance with human history reveals the magnitude of human suffering brought about by such supernaturalist thinking operating under this perfectly valid--but unsound, if supernaturalism is not true--syllogism.
Widespread human belief in pseudoscientific, paranormal, and preternatural phenomena has its basis in the initial human acceptance of supernaturalism. It is ironic that so many religions criticize and condemn Pagan and New Age beliefs in pseudoscience and the paranormal--these are cases of competing irrationalisms, fighting among themselves for turf and influence but sustained by their underlying commonality: a rejection of naturalism. Without naturalism, anything is permitted. For example, the reality of parapsychological phenomena (telepathy, telekinesis, clairvoyance, precognition, etc.) is controversial and under investigation by both parapsychologists and legitimate scientists, but Uri Geller claims that, "Parapsycholgogy is true because God exists!" Well, who can argue with that! It is common for religionists to very unfairly criticize naturalistic humanists--who have no absolute moral beliefs--with the slogan, "You believe that if it feels good, do it!" In fact, however, just the opposite prevails: supernaturalists believe that if it feels good, believe it! And since one acts on one's beliefs, supernaturalists end up doing what feels good, as history has amply shown.
Naturalism is not an assumption or presupposition on the part of scientists, a common claim by critics of science; it is, instead, a hypothesis that has been tested and repeatedly corroborated, and so has become reliable knowledge itself. I have justified the truth of naturalism by using the same methods (evidence, reason, testing, corroboration) that one would use to demonstrate the truth of some fact or theory of nature. Whatever the value of such an attempt, the question now is: How can one possess confidence in the scientific method? That is, how can one demonstrate that the reliable knowledge that science produces is the best, most truthful knowledge that humans can obtain, and that it should therefore be believed in preference to knowledge obtained by other methods of knowing? Entire books have been written to answer these questions using sophisticated logical and epistemological arguments (mostly older books by neopositivists--such books are less common now!); I could reference them, but will refrain. Instead, I will justify the reliability of scientific method by a single pragmatic argument: Of all human disciplines or methods of inquiry, science alone has fulfilled its promises of a better, progressive, greater understanding of and control over nature. Humans depend on science--and its applied offshoot, engineering--for food, clothing, shelter, energy, medicine, communication, transportation, information, weapons, entertainment, etc. Our modern civilization would collapse without the continued support of science. No other human endeavor can make these claims; science, solely because of its method, is the most successful human endeavor in history. The others don't even come close. Because of the immense and continuing success of science, it and scientists have achieved great legitimacy and prestige among both intellectuals and the public. This fact will be important later in this essay.
Phillip Johnson (1995, p. 68) calls this argument the "argument from success," and although he recognizes it as a good argument, he criticizes it by claiming that "all statements made in the name of science are not equally reliable," and "the technical achievements of science" are not on the same level as statements concerning such "vast theoretical scenarios" as the prebiotic chemical origin of life, evolutionary biology, and cosmology. Johnson's counter-argument is fallacious, of course; all scientific statements are the product of an identical method and therefore have the same reliability. Johnson may be surprised to learn that safe bridges, electronic appliances, hybrid crops, reliable and abundant energy, and the things he mentions--"airplanes, nuclear bombs, antibiotics and computers"--all depend on "vast theoretical scenarios" for their existence and success. They all depend on the reliable theoretical structure of science. But perhaps he knew this, and was merely using the common creationist tactic of falsely distinguishing technical "facts" from scientific "theories." Scientists have as much confidence in the theory of evolution as they do in other scientific theories; all that scientists really have, after all, are their theories, which just happen to consist of the most reliable knowledge that humans can possess. As another example of Johnson's misrepresentation in this context, he says that scientists freely concede that "the materialistic theory of mind is only a hypothesis" (p. 69). Of course it is a hypothesis, a highly reliable hypothesis that has been tested and corroborated to such an extent that it can legitimately be considered a scientific fact, something that only someone perverse or irrational would persist in denying. The existence of gravity and the occurrence of evolution fall in this same category of scientific facts. "Only a hypothesis" and "just a theory" must be the most frequent phrases found in any computer word search of the creationist literature.
The Limits of Science
Since I am a scientist speaking at a philosophy conference, perhaps I should clarify some issues. Some may suggest that my defense of science is an example of scientism. Scientism has been defined as "the belief that science, especially natural science, is much the most valuable part of human learning--much the most valuable part because it is much the most authoritative, or serious, or beneficial" (Sorell, 1991, p. 1). I would say that this definition is an overstatement, especially since it is exactly what I believe, and I am not scientistic. Scientism is, rather, the belief that science is the only valuable part of human learning, that knowledge comes only through the methods of investigation available to science, that science by itself gives us reliable answers to questions about morality and epistemology, that science enables us to solve all serious human problems, and that science will give us a comprehensive and unified understanding of the meaning of the universe. I believe none of these. Science may illuminate serious ethical, epistemological, aesthetic, and metaphysical problems and suggest solutions, but, in the end, many human problems must find solutions in human philosophies, even if the answers are unsatisfactory for a variety of reasons.
Science does give us reliable knowledge about the material universe, that is, about everything in the universe that is made of matter and energy. Reliable knowledge, or justified true belief, is knowledge that has a high probability of being true because it has been justified by a reliable method. Furthermore, science is not just the best method--it is the only method that humans possess (at least, the only one discovered so far) that provides such reliable knowledge about the material world. Other ways of knowing about the material world give us knowledge of nature, certainly, but that knowledge is not reliable, for it may be true or false and we can't be sure which. Non-scientific methods, therefore, don't even come close to science as a method of understanding and explaining the cosmos. Since we humans are ourselves material, inhabit a material world, and depend on this material world for our existence, sustenance, and survival, it seems to me that the discipline that allows us to reliably understand and control the material world must be much the most valuable, authoritative, serious, and beneficial part of human learning. But certainly not the only part.
Science is less reliable if we examine more difficult questions about the relationship of the material world to the immaterial world of the conscious mind: the world of thoughts, ideas, beliefs, dreams, truths, values, morals, meanings, purposes, intentions, reasons, logical relationships, imagination, free will, and self-awareness. All of these elements in a second, immaterial world are undoubtedly part of the nature, and science certainly helps to investigate them and provide reliable knowledge to help us understand them, but, on its own, it has not provided final answers to our questions about them. Perhaps, in principle, it can ultimately do this, but so far it has not. Philosophy is therefore required along with science in our investigation of the immaterial world, although their combined reliability is no sure thing, either. The immaterial world includes, of course, the nature of truth and knowledge, and therefore includes the ultimate reliability, certainty, and objectivity of scientific knowledge. Thus, I am happy to acknowledge the vital importance of philosophy in the effort to explain how science works. I emphasize that science and philosophy are both involved in understanding and explaining all non-material aspects of nature. Furthermore, I emphasize that philosophy of science explains how science works--it does not and should not tell scientists how to work. (This final point is important in our present discussion, in which theistic philosophers are insisting that science consider the supernatural in its practice.)
We turn now to the really difficult, perhaps intractable, questions about the immaterial world. Do ideas, truths, logical relationships, etc., exist independently of a conscious mind? I don't know. If materialism is true, mind does not exist independently of a brain, so we would at least have to have a material world to have an immaterial world. This explanation seems most likely and has the most evidence in support of it. If one is a dualist, then mind exists independently of the material world, but there is little support for that philosophy today; in fact, Daniel Dennett (1996, p. 24) says that dualism has "been relegated to the trash heap of history," so this pretty well decides that question. The next question must be: Does an immaterial world--with its ideas, truths, morals, etc.--exist independently of matter and energy? This is the philosophy of idealism, which we can relegate in the same way as dualism, sensu Dennett. But the ultimate question must be this: Does yet a third, transcendent world exist independently of both the material and immaterial natural worlds. An affirmative answer to this question requires belief in supernaturalism, so the answer is probably no. 
Supernaturalists identify--misidentify, I believe--the immaterial world of the human mind, which obviously exists and is part of nature, with the transcendental world of their supernatural beliefs. This practice is so pervasive that I must briefly discuss it here. Let us name and classify the three philosophical worlds and their elements: First, the material or physical world of nature that includes matter and energy; second, the immaterial world of nature that includes mind, ideas, values, imagination, logical relationships, etc.; and third, the transcendental world of supernature that includes gods, spirits, souls, etc. Belief in the first two worlds with denial of the independence of the second constitutes materialism, belief in worlds one and two without necessary denial of the independence of the second constitutes naturalism, while belief in all three worlds constitutes supernaturalism. While the identification of brain with conscious mind is relatively easy, supernaturalists invoke this third world and identify--misidentify, in my analysis--conscious mind with soul. Similarly, naturalists identify brain with imagination and emotion, but supernaturalists misidentify imagination and emotion as transcendence. Similarly, brain is self is misidentified as spirit; brain is dreams (or psychosis) is misidentified as revelation; brain is imagined all-loving, all-powerful authority figure is misidentified as a deity; unexplained natural phenomena are mysteries misidentified as miracles; wrongful acts are immoral acts are misidentified as sins, and so forth. In short, supernaturalists are exploiting the uncertainty and ignorance of science regarding the second world of immaterial elements to create and justify their belief in a third world of supernature. Supernaturalists would object to this analysis, I am sure, but it explains to me why they continue to harbor their beliefs despite centuries of being unable to demonstrate even the slightest bit of empirical evidence or formulating a single unrefuted valid reason. They think they have evidence and valid reasons, to be sure, but I think they are misinterpreting elements of a perfectly natural but non-material second world to sustain their mistaken belief in a supernatural third world.
Science and Postmodernism
Science has, as have other intellectual disciplines, been challenged by postmodern thought. Such thought questions whether human reason conforms to any objective standards of belief. Postmodernism says that there is no such thing as objective, truthful knowledge in art, literature, history, philosophy, and even (or especially!) science. It seems useful to briefly consider these concerns here. There are at least three criticisms postmodernists level against science:
Externalism -- The criticism that scientists are humans who perform their work within a culture or society, and their findings and knowledge claims reflect that society and are motivated, determined, and legitimatized by cultural, economic, gender, and political forces within that society, but external to science. Whatever biases or prejudices exist in a society will be found in its science; thus, scientists and their scientific conclusions and theories have been racist, misogynist, sexist, anthropomorphist, jingoist, mercantilist, etc., all reflecting external societal forces or pressures.
Relativism -- The claim of scientists to an objective, progressive truth is refuted, according to postmodernists, by the ever-changing nature of scientific truth: one theory replaces another, a paradigm becomes insupportable and is overthrown by a competing paradigm in a scientific revolution. There is no objective truth, only subjective and relative truth that can and will be succeeded by yet other subjective and relative truths. The relativity of truth and subjectivity of knowledge are essential components of postmodernism to which science must respond. Indeed, postmodernism even challenges rationalism, the possibility of humans being able to reason correctly to reach valid conclusions.
Subjectivism -- The idea here is that science is a human or social construct, not a system of reliable, objective knowledge gained by application of a reliable method. Scientists, in this postmodern view, create their explanations, laws, and theories by constructing a belief system, not by discovering one using objective methods to analyze nature. Social constructivists, the post-modernists who claim this, focus on language and attempt to free it from concepts and referents; specifically, one cannot have confidence that meaning exists independently of language, and therefore questions whether such words as "truth" have objective meaning. Social constructivists conclude that knowledge or belief systems are unavoidably personal and subjective. In other words, scientists create their understanding of nature by imposing their apriori, subjective beliefs, biases, assumptions, and presuppositions on nature, not by--as they claim--objectively and disinterestedly investigating nature to discover what is there. Finally, social constructivists analyze intellectual disciplines by taking apart--deconstructing--the literature of that discipline, thus revealing its hidden, subjective meanings; for this reason, social constructivists are sometimes known as deconstructionists.
The postmodernist critique of science undoubtedly finds its strongest expression in the historicist school of the philosophy of science, a movement opposed to the logical positivist school that was dominant until the early 1960s. I have no trouble identifying Thomas Kuhn, Paul Feyerabend, and others as postmodernists, and although I acknowledge that they poked holes in the remarkable edifice of positivism (logical positivism, logical empiricism) of Rudolf Carnap, Hans Reichenbach, Carl Hempel, Ernest Nagel, and others, I am not convinced that positivism should be totally abandoned, as some suggest, but only selectively abandoned. Logical positivism was prescriptive and ahistorical, and therefore unquestionably did not characterize the true nature of science, but its emphasis on empirical evidence and logical structure cannot be discarded. Present-day philosophers of science are attempting to forge a new, third-generation, synthetic philosophy of science based on the best attributes of the previous two schools; this new school is called, remarkably enough, the naturalist school. This turn or return to naturalism is now dominant among philosophers of science (Kitcher, 1992; Callebaut, 1993). These philosophers believe that matters of fact are as relevant to philosophical theory as they are to science (a positivist stance), but they also claim that the history of scientific discovery and theory formation is vital to understanding and explaining the workings of science (an historicist stance). I think the naturalist school is a very positive development in the history of philosophy of science, although I point out that they come to no agreements concerning the objectivity and credibility of science. Their work is still in progress.
The surest sign that postmodernism is wrong is that postmodern critiques of science have had absolutely no effect on the practice of science or the continuing achievements of science. If there had been any truth at all to postmodernism, scientists would have changed their scientific methods and procedures to try to escape the postmodern pitfalls of relativism, subjectivism, and externalism. The fact that few scientists know or care about postmodernism, and none have been influenced by it, speaks volumes. (Karl Popper's neopositivistic falsificationism, on the other hand, has--for better or worse--been remarkably influential.) Some scientists have taken the time to understand postmodernism and, in their minds, it is easy to refute (Gross and Levitt, 1994; Gross, Levitt, and Lewis, 1996). Although some philosophers probably don't believe this, scientists are and have long been aware of the minefields of relativism, subjectivism, and externalism, and they firmly believe that the scientific method, as it is now and as it has long been practiced, eliminates--not just minimizes--these problems. (Admittedly, this process of elimination is historical and may take years, decades, or even centuries!) I have long believed this myself, and now that I have become acquainted with the postmodern critiques of science, I still believe it. Avoiding relativism, subjectivism, and externalism is what scientists learn in science school. The end result of the scientific method is the most reliable knowledge that humans can possess, although not necessarily ultimate, absolutely true knowledge (whatever that means), but that is good enough and better than the alternative.
Naturalism and Materialism
So many metaphysical naturalists believe in metaphysical materialism that naturalism and materialism are often confused with each other. This confounding is not serious in most circumstances, but in this essay I must clarify their distinctiveness to prepare for the discussion of the methodological/ontological assumption/necessity of naturalism in science. The primary purpose of this paper is to examine the claims of Phillip Johnson (1990, 1991, 1994a, 1994b, 1995) and the authors in The Creation Hypothesis (Moreland, 1994) that scientists, by advocating and teaching the fact of evolution, are promoting the unconstitutional establishment of a religion (metaphysical naturalism) in the intellectual life of our country, and that true, value-neutral (i.e. metaphysical-neutral) science should consider supernatural explanations as well as natural ones. In her otherwise astute and properly highly critical review of Johnson (1990), Eugenie Scott repeatedly confounds naturalism and materialism, and my agreement or disagreement with her depends on which one she really means, since her refutation of Johnson's claims concerns on the problems I am addressing.
Her review (Scott, 1993, p. 43) of Darwin on Trial (Johnson, 1991) contains the following passage:
Johnson manages to set up another strawman that does not accurately reflect the real relationship between evolution and religion. Evolution is presented as a "fully naturalistic process," implying an antithesis between evolution and the supernatural....Johnson confuses the necessary methodological materialism (or naturalism) of science with philosophical materialism/naturalism. Science neither denies nor opposes the supernatural, but ignores the supernatural for methodological reasons.
In an important paper, Scott (1996, p. 514-515) repeats this idea:
Creationists...claim that the rejection of the supernatural in modern science is a function of "naturalism" (materialism), a philosophy that defines reality only in terms of material causes. Because evolutionary scientists supposedly are caught up in a metaphysical viewpoint that rejects the possibility of a creator, creationists contend that evolutionists are unable to countenance evidence for supernatural intervention in the history of life. Actually, modern science has omitted the supernatural for methodological, not philosophical, reasons....[W]e simply get better explanations by ignoring the possibility of supernatural intervention or causation. Much confusion exists between materialism as a philosophy, and the methodological materialism that informs all of modern science. It is logically possible to decouple philosophical and methodological materialism, and individual scientists who are believers do it all the time. Gregor Mendel was certainly not a metaphysical naturalist, but he developed his understanding of the rules of heredity using methodological materialism....I stress methodological materialism as a tool to understand the natural world better....
Actually, naturalism is not a philosophy that defines reality only in terms of material causes. Again, in the same paper (p. 518):
First, science is a limited way of knowing, in which practitioners attempt to explain the natural world using natural explanations. By definition, science cannot consider supernatural explanations...So by definition, if an individual is attempting to explain some aspect of the natural world using science, he or she must act as if there were no supernatural forces operating on it. I think this methodological materialism is well understood by evolutionists.
Again, in the same paper (p. 519):
Scientists, like other teachers, must be aware of the difference between philosophical materialism and methodological materialism and not treat them as conjoined twins. They are logically and practically decoupled.
There is an important point in these quotations--the distinction between methodological and ontological (Scott uses the term "philosophical") naturalism--and I do not want to see it lost by the practice of confusing naturalism with materialism. Johnson, also, mistakenly conflates naturalism and materialism in a footnote (1995, p. 38): "'Naturalism' is similar to 'materialism,' the doctrine that all reality has a material base. I prefer the former term because it avoids any confusion by the ordinary language distinction between matter and energy...." He uses the term naturalism exclusively from then on, which makes his arguments quite clear (but not thereby valid). I don't think he needs to worry about confusion between matter and energy; both of these are material, both being composed of elementary particles, as he recognizes. He is also correct, as he states later in that footnote, that both naturalists and materialists understand nature to be "all there is," but he is incorrect to state that they also understand nature to be "fundamentally mindless and purposeless." Humans are both material and part of nature, and they are not mindless and purposeless. Presumably he means that, except for humans, philosophical naturalists understand nature to be fundamentally mindless and purposeless, and here I would agree. Of course, this doesn't eliminate the possibility of supernatural mind and purpose in nature; the only requirement would be the demonstration of its existence and mechanism, which is up to the supernaturalists to provide. We are still waiting.
The point in this section is this: Of course scientists adopt methodological materialism; everyone in the world does, even metaphysical idealists. This is hardly controversial or interesting. Scientists are also methodological monists and realists. Scientists and almost everyone else do not have the time to contemplate whether subatomic particles or ideas are primary, whether there is one ultimate substance or two, or whether the universe is real or an illusion. (Materialism is not, I wish to emphasize, an assumption or presupposition on the part of scientists; science would be equally successful if idealism, dualism, or antirealism, rather than materialism, were true. I consider materialism to be a working hypothesis--a metahypothesis, as discussed below--whose essential validity has been corroborated by experience over the centuries.) The important question we face is the adoption of methodological and ontological naturalism by science, which is certainly the real concern of Scott, Johnson, and myself, so let's not confuse ourselves and others by using inaccurate terminology.
The Origin of Naturalism and Its Relation to Science
Science and naturalism are not the same thing. Science is a way of knowing, a powerful method that uses three epistemologies in a unique and systematic way to discover the secrets of nature. Science is not metaphysical. Naturalism is a philosophy, a metaphysics or ontology that posits a particular picture of reality, being, and existence that excludes the supernatural. What is the origin of naturalism and its relationship to science? I can deal with these issue only briefly and superficially.
Naturalism did not exist as a philosophy before the nineteenth century, but only as an occasionally adopted and non-rigorous method among natural philosophers. It is a unique philosophy in that it is not ancient or prior to science, and that it developed largely due to the influence of science. Naturalism begins with Galileo and Isaac Newton, who began to explain nature by theoretical and experimental descriptions of matter and their motions. Their correct and lasting discoveries were all made within a completely naturalistic methodology. The outstanding success of this method led others to emulate them, and a comprehensive understanding of the universe was initiated. Galileo and Newton were not ontological or metaphysical naturalists; they did not hesitate to attribute supernatural causes to things that they thought could not be explained by natural causes. Until the late eighteenth century, most scientists agreed with them, but the influence of the Enlightenment led scientists, such as Antoine Laurent Lavoisier, Pierre Simon de Laplace, and James Hutton to abandon all supernatural explanations in favor of natural ones. Biology was the last science to be "naturalized"--by Jean Baptiste Lamarck and Charles Darwin. I am convinced that all of these men intentionally tried to emulate Newton: to be the Newton of his day and science by finding purely natural laws to explain natural processes and objects in their respective areas of expertise.
Under the influence of philosophers John Herschel and William Whewell, methodological naturalism was systematized and promulgated, so that, by the end of the nineteenth century, methodological naturalism was embedded in science. Naturalism as a necessary part of science thus developed gradually as science developed gradually with the practice and understanding of scientists. Appreciation of the hypothetico-deductive method and empirical-skeptical testing of hypotheses required naturalism, since legitimate, scientific supernatural predictions cannot be made or supernatural conjectures tested. Holdout scientists who persisted in using supernatural explanations were gradually abandoned intellectually by their students and colleagues, and they eventually died with no successors. There was never a single moment or event when supernaturalism was evicted from the structure of science and replaced by naturalism. However, by the turn of the twentieth century, supernaturalism had been methodologically eliminated and the scientific method came to be identified as naturalistic. The last legitimate creationist scientists died around this time, and creationist pseudoscience was soon to be born. Thus, methodological naturalism became historically an essential part of science.
As methodological naturalism became a necessary part of science, it simultaneously became a necessary part of critical inquiry, since as I emphasized earlier, scientific method is not an esoteric method of inquiry, but only the rigorous, systematic application of a method continuous across many disciplines. Procedural, methodological naturalism in all areas of intellectual inquiry (except theology) meant the procedural, methodological suspension of belief in supernaturalism, and I think this, more than anything else, led to the rise of liberal religions and the freethought and humanist movements, and to the reactions against them, the fundamentalist religions and religious movements. The spread of methodological naturalism in scientific, religious, social, political, and economic institutions in the late nineteenth century created the modern world and the concomitant psychological crisis of meaning in which people still find themselves today: they do not know what to believe about themselves and the world in a universe devoid of transcendant meaning and purpose, and therefore attempt to find solutions in pseudoscience, the paranormal, strange cults, and extreme political, social, and economic ideologies, as much as in science and traditional religions. Today, we take for granted the dominance of critical thinking in all areas of intellectual inquiry, which is why today supernaturalism finds itself increasingly irrelevant, attacked, and unsustainable, and is therefore undergoing a reactionary resurgence to save itself. The specific reason is not because people claim to not believe in supernaturalism any more (they don't claim this), or because it is untrue (this has never been demonstrated), but because methodological naturalism is so effective, powerful, and successful, while methodological supernaturalism is not effective and is, in fact, positively ineffective and counter-productive, especially in attempts to understand the natural world. An education which includes science and other disciplines that inculcate critical inquiry, as most do, only reinforces this perception.
Ontological naturalism developed subsequently from this methodological naturalism. Under the influence of Charles Sanders Peirce, the first great American philosopher, naturalism developed--primarily in the United States--with the writings of F. J. E. Woodbridge, Morris Cohen, John Dewey, Ernest Nagel, and Sidney Hook (Ryder, 1994). Naturalism, as a twentieth century American philosophy, reached its zenith during the 1930s and 1940s. It has been kept alive by the work of philosophers Paul Kurtz (1990), David Papineau (1993), and Kai Nielsen (1996), and it is making a resurgence, in a less formal guise, in the philosophy of science by the work of Michael Ruse (1986), David Hull (1988), Philip Kitcher (1992, 1993) , and many others. Explicitly naturalistic humanist authors such as Dewey, Hook, and Kurtz have developed a form of naturalism called pragmatic naturalism, which is much more than a straightforward ontological system, involving, as it does, ethical, social, and political components in addition to metaphysical ones. As such, pragmatic naturalism more or less provides the philosophical underpinnings of naturalistic humanism.
Naturalism is almost unique in that it would not exist as a philosophy without the prior existence of science. It shares this status, in my view, with the philosophy of existentialism. Scientists first discovered the meaninglessness and purposelessness of the mind-external universe, and established this fact in the philosophy of naturalism. For example, a frequently quoted phrase describing the naturalistic view of existence is that of George Gaylord Simpson (1967, p. 345), one of the great paleontologists and evolutionary scientists of this century; he said, "Man is the result of a purposeless and natural process that did not have him in mind. He was not planned." This fact consequently forces humans, largely against their wills, to deal with their unplanned existence by creating meaning and purpose entirely within their own minds by their relations with other human minds, not a pleasant prospect or experience. (I have humorously labeled this insight, for what it is worth, as "science precedes existence precedes essence.") Existentialism deals with human realization of the fact of natural meaninglessness and purposelessness, and the task of accepting and overcoming it, if possible.
But none of this answers the main question: How important is methodological and ontological naturalism for science to work and be successful? Must ontological naturalism be true or assumed to be true to practice science, or is it irrelevant to the scientific method?
Methodological Naturalism and Ontological Naturalism
Is it true that science does not entail a belief in metaphysical naturalism, but only the temporary, uncommitted adoption of methodological naturalism? Methodological naturalism is the adoption or assumption of philosophical naturalism in scientific belief and practice without really believing in naturalism. Ontological or metaphysical naturalism (the two terms are synonymous) is the claim that naturalism is the correct descriptor of existence or reality, i.e. the act of sincerely accepting that naturalism is true. (Ontology and metaphysics usually mean the same thing--a philosophical understanding or description of existence, being, and reality--so naturalism can be prefaced by either "ontological" or "metaphysical" and mean, in the present context, that a person believes in naturalism as the ontology or metaphysics that explains reality. I prefer not to use the term "philosophical naturalism" in this context, since even a methodological naturalist is using naturalism as a philosophy--just not being sincere about it.) One might say, "Isn't it rather silly to assume the truth of a philosophy--just for your scientific work or for scientific beliefs about the universe--that you don't actually believe?" I do say it: I think such a stance is logically and morally absurd, although I recognize it as legitimate in a certain pragmatic sense, which is to have it both way--to save appearances--always a popular attitude among humans. But this is not the same as saying that science entails ontological naturalism.
Methodological naturalism combined with supernaturalism is perhaps the most popular metaphysical position in the United States today. All theistic scientists adopt such methodological naturalism, as well as the 40-50% of the U.S. population who believe in science, evolution, and also in God, the view known as "theistic evolution" (all of these individuals would be metaphysical supernaturalists). Of the others, 40-50% believe in creationism and God (also all supernaturalists), and the remaining 10%, including probably most scientists and philosophers, are nontheist believers in science and evolution (so are all metaphysical naturalists). Therefore, no more than 10% of Americans sincerely believe in ontological naturalism; 90% are ontological supernaturalists with about half of these being methodological naturalists when it suits them.
These figures belie the notion that metaphysical naturalism is some sort of secular religion being established in the public schools by atheistic scientists (Johnson, 1990, 1995). It should be obvious that metaphysical theistic supernaturalism is the established civil religion in this country. What really bothers Phillip Johnson is that informed, educated, scientifically-knowledgeable people--always a minority--are largely ontological naturalists and don't agree with his brand of God-active-in-nature theism. We may dispose of his claim that metaphysical naturalism is an established civil religion very easily. First, from the figures discussed above, ontological naturalism is distinctly the minority position in our population by a huge margin. Even among intelligent, educated people it is the minority philosophical position (this group, like most, is not really knowledgeable about science and its philosophy).
Second, metaphysical naturalism is not a religion by any definition of religion, even the open-ended ones, such as "the means by which one derives answers to ultimate questions." Although naturalism may answer ontological questions, this hardly exhausts the superset of "ultimate questions." The establishment clause of the First Amendment deals with religions, not metaphysical philosophies. Naturalistic humanism, a world view that promotes metaphysical naturalism along with other ethical viewpoints (such as democracy, humanitarianism, freedom of conscience, and moral relativism), would be a better candidate for Johnson's established religion, but its alleged religious status has been litigated in courts on a number of occasions and found to be without foundation. Metaphysical naturalism makes no moral or normative statements, and it advances no social concerns, both of which seem to me to be essential elements of any religion.
Third, if one really objects to the establishment of a philosophy in violation of the First Amendment, why doesn't Professor Johnson rail against the establishment of metaphysical realism--not only in schools, but in all agencies of the federal government and all U.S. corporations, and one that I would agree is insidiously and pervasively established. What Professor Johnson really wants, of course, is to have his own brand of theism established rather than other brands of theism and nontheism, and to achieve this he uses one of the oldest rhetorical tricks in the book: overstate your case by claiming that the intellectual opposition has an advantage in numbers or power that must be opposed by the emotional and active involvement of every reader or listener. He probably would agree with those who claim the news media is overwhelmingly liberal--have they listened to the radio or read a newspaper lately?
Let's get back to the main topic, one of legitimate disagreement and importance--the use of methodological or ontological naturalism by scientists in practicing the scientific method. I extensively quoted Eugenie Scott above regarding her use of the terms naturalism and materialism. Her primary, quite valid point is that science adopts methodological naturalism--not ontological naturalism. She says that science "neither denies nor opposes the supernatural, but ignores the supernatural for methodological reasons," that "modern science has omitted the supernatural for methodological, not [ontological], reasons," that "it is logically possible to decouple [ontological] and methodological [naturalism], and individual scientists who are believers do it all the time," and "by definition, science cannot consider supernatural explanations," so "if an individual is attempting to explain some aspect of the natural world using science, he or she must act as if there were no supernatural forces operating on it." Science cannot consider or deal with the supernatural for many good theoretical and methodological reasons, so a scientist must adopt, at least, methodological naturalism. Scott's description of how science works is extremely common among scientists and the informed public, and has not really been controversial (until now); Frederick Grinnell (1994) also defends its use with good reasons I do not repeat here. Even Phillip Johnson (1994, p. 15) says the following:
Methodological naturalism--the principle that science can study only the things that are accessible to its instruments and techniques [and, I might add, to its method]--is not in question. Of course science can study only what science can study. Methodological naturalism becomes metaphysical naturalism only when the limitations of science are taken to be limitations upon reality.
Precisely. Science investigates the natural, but the supernatural may exist as part of ultimate reality, so let's not say that the natural is all that exists because that is what science investigates (Johnson (1995, p. 212) emphasizes this point again in his latest book). There seems to be no question that scientists must, at a minimum, practice methodological naturalism (but I will discuss objections to this statement below). Methodological naturalism in science seems to be acceptable and uncontroversial. Not so, however, for the alleged link between science and ontological naturalism. Phillip Johnson, in his many books and articles, maintains that teaching evolution as a fact of science establishes ontological naturalism in intellectual society among people who would not and do not believe such a philosophy. Is he right?
Why do Scott and others go to such great lengths to decouple the two aspects of naturalism? The primary reason is that they believe that this is the correct scientific and philosophical position, but Scott's important second reason is to protect the religious sensibilities of theistic evolutionists, the largest class of supporters of scientific evolution, who also happen to be the largest class of opponents to scientific creationism.  She (1996, p. 518) takes William Provine, Paul Kurtz, and Daniel Dennett to task for promoting metaphysical naturalism and materialism because they, she claims, argue that "Darwinism makes religion obsolete, and [they] encourage their colleagues to argue likewise." However, I suspect that these individuals have many reasons for rejecting religion, or whatever specifically they object to (since the word "religion" can refer to so many things), and I doubt that Darwinism (whatever that means) is the sole reason.
Scott correctly argues (p. 519) that the naturalistic world of science precludes it from rejecting the possibility of the supernatural. After stating her repeated distinction between ontological and methodological naturalism, she says, "if it is important for Americans to learn about science and evolution, decoupling the two forms of [naturalism] is essential strategy." In her conclusion (p. 520), she states the following:
I suggest that scientists can defuse some of the opposition to evolution by first recognizing that the vast majority of Americans are believers, and that most Americans want to retain their faith. It is demonstrable that individuals can retain religious beliefs and still accept evolution as science. Scientists should avoid confusing the methodological [naturalism] of science with metaphysical [naturalism].
Protecting the religious sensibilities of theistic evolutionists seems a poor reason for insisting that scientists decouple methodological and ontological naturalism in their explanation of science, and I also intensely dislike referring to this as a "strategy," as if we are going to keep our followers in the fold by following a strategy. Scott's primary reason, however, is to ask that scientists properly explain the scientific method. Science, an inanimate discipline, demands methodological naturalism from its practitioners for science to work properly (as explained in a preceding section), and science could care less whether metaphysical naturalism is true or not, or whether its practitioners believe it or not. Restricted to being a descriptor of science and the scientific method, Scott's admonitions are unobjectionable and uncontroversial, and I fully support them.
Scientists and others who believe in science, however, are humans, and their beliefs are another story. How convincing is the argument made by theistic methodological naturalists, individuals who believe in both science and the supernatural, that evolution--or any statement of science--is firmly established by a naturalistic method in which they don't really believe? Not very convincing. I find difficulty with Scott's insistence that methodological and ontological naturalism are "logically and practically decoupled." I maintain that the practice or adoption of methodological naturalism entails a logical and moral belief in ontological naturalism, so they are not logically decoupled (but could remain practically or pragmatically decoupled for those who wish or must for personal reasons). Most scientists presumably practice naturalism in science because they believe in naturalism as an ontology. Theistic scientists, on the other hand, only assume--do not really believe--methodological naturalism, because they are actually supernaturalists (this argument also applies to the much larger group of non-scientists who believe in both theism and the conclusions of science, such as evolution).
Do theistic scientists think they are playing a game, in which they do science during the day with naturalistic methods, but at night go home and leave naturalism behind in the laboratory, since they don't really believe it describes a true picture of reality? How can an individual scientist not believe that the work he or she is doing actually discovers true and reliable knowledge about reality and still be motivated to perform that work? One might reply that his or her work does indeed discover such reliable knowledge about a part of reality, the natural part, and the other, supernatural, part is unknowable by science but presumably knowable by some other method (revelation, faith, authority, etc.). But this distinction is based solely on a definition, not on any real knowledge of reality. In effect, it involves the identification of the supernatural in a description of the realm of the natural, and thereby justifies one's adoption of methodological naturalism by ignoring methodological naturalism. I think theistic/supernaturalistic methodological naturalists are being illogical in this instance.
Theistic naturalists must believe in naturalism to methodologically assume or adopt it in science, and they cannot logically maintain a belief in supernaturalism at the same time unless they maintain that there is absolutely no connection at all between the natural and supernatural worlds. But this is something no supernaturalist maintains. Even the most naturalistic theistic naturalist--a deist who claims that God is the ultimate Creator of the universe, but that everything after that singular event is natural and operates by natural causes--believes in a supernatural origin of the universe. But ontological naturalism makes no exception for the origin of the universe. It must have been natural, too. For supernaturalists who believe in miracles or the dogmas of Christianity, the hurdle is even higher. It is not logically possible for them to describe nature naturalistically when, in fact, they believe in supernatural violations of natural law, i.e. the manifestation of miracles. These arguments suggest to me that methodological naturalism, itself alone required by science, is logically untenable for humans unless one is simultaneously an ontological naturalist.
The moral entailment of ontological naturalism by methodological naturalism does not create an ethical lapse among those supernaturalists who assume methodological naturalism, but something similar to an insincerity or want of courage; theistic naturalists want to both believe in the claims of science--a prestigious, powerful, intellectual knowledge system--but also want to escape the opprobrium of being known as ontological naturalists--that is, as atheists! Theistic naturalists say, in effect, "I don't ultimately believe in naturalism, but I believe in the reliability of knowledge gained by its assumption, and I expect you to believe in it too!" As with all moral arguments, one can accept or deny this argument on just about any ethical basis, so I do not claim it has the same status as the logical arguments above. I merely want to suggest that supernaturalistic methodological naturalists may wish to examine their metaphysical beliefs more closely, since I think they are illogically engaging in self-deception. In the words of the Philosopher, "The unexamined life is not worth living." Theistic naturalists might reply that, as a practical matter, they need to get on with their lives, practice and believe in science, live in communities of theists and supernaturalists, and not really examine their metaphysical beliefs too closely, since life is too short for indulging in such inconclusive intellectual activity. They might quote the words of Anonymous, "The unlived life is not worth examining."
The power of science lies in the fact that it is not a metaphysics, but an epistemological method; it has no prior commitment to a description of any specific reality, being, or existence, that is, a commitment to any specific metaphysical philosophy. It makes no assumptions and has no presuppositions about its subject matter or methods. I fully realize that critics of science claim just the opposite: that science assumes that the universe is real (realism), that matter and energy constitute all of the universe (materialism), that immaterial things like consciousness, mind, and ideas are ineluctably associated with material objects like the brain (monism), that the natural universe is all there is or all we need to consider (naturalism), that the universe is comprehensible (comprehensibility), that natural processes follow natural laws by cause and effect relationships (causation), that natural laws do not change through space and time (actualism), etc., and if these assumptions were simply not made, science would be more open to supernaturalist hypotheses and intelligent design theory. To assume the truth of any of these, in my opinion, would indeed make science a metaphysics rather than an epistemology. Instead, science treats these high-level propositions as working hypotheses, what I would call metahypotheses. These metahypotheses (realism, materialism, naturalism, monism, causation, actualism, etc.) have themselves been repeatedly tested and corroborated throughout the centuries, and like other, ordinary, corrborated hypotheses in science, we have great confidence that they are true. Metahypotheses can be considered reliable knowledge, as true as anything we know, and they are recognized to be important heuristic and pragmatic parts of the scientific enterprise. The point is that everything in science is hypothetical, the methods and rationales--the metahypotheses--as well as the objects and processes--the ordinary hypotheses.
Ordinary hypotheses must be testable and falsifiable by empirical investigation and rational arguments to be scientific. In scientific practice, ordinary hypotheses that deal with natural objects and processes are, in fact, often falsified during testing by experimentation or subsequent observations. What about metahypotheses? Can they be falsified? Of course they can, but not easily. To falsify a metahypothesis, its antithesis must be shown to be true. For example, a demonstration of a supernatural event, being, or process would falsify naturalism. A demonstration of an idea or consciousness existing independently outside of a animal brain (or supercomputer) would falsify monism and probably also materialism. A demonstration of a natural law such as gravity operating differently in another galaxy or natural selection operating differently in Earth's ancient past would falsify actualism. A demonstration of an uncaused effect would falsify causation. Unfortunately, although the great majority of humans believe that these demonstrations have occurred, they actually have never happened (excluding the quantum realm, of course, which I ignore here). The problem is how we would recognize such a demonstration if it in fact occurred. I don't know. And since I don't believe that any such demonstrations are possible, I can't think of any way to falsify metahypotheses that I would actually believe.
The falsification of actualism, monism, materialism, and causation are difficult, but at least conceptually possible in theory. The falsification of naturalism, however, is in another class altogether: it is probably impossible. David Hume in 1748 discussed this very problem in the famous chapter "Of Miracles" in his An Inquiry Concerning Human Understanding. Evidence that appears to support occurrence of a miracle (violation of natural law or naturalism) could just as easily be accepted as a demonstration that our knowledge of the natural world is incomplete, that is, its occurrence falsifies our current scientific conception of the natural world. What is needed to demonstrate a miracle--or any supernatural event, being, or process--is criteria that properly distinguishes between true supernatural violation of natural law that does not constitute a falsification of such law and those apparent transgressions which are truly falsifying because of our incomplete understanding of nature. Such criteria do not exist, because such criteria would have to be independent of both nature and supernature, a seeming impossibility. Another way to state this argument is as follows: Proponents of the miraculous or supernatural would be obliged to produce evidence that simultaneously shows that (1) the overriding of natural law by a supernatural power does not constitute true falsification of the laws of nature because (2) we have a complete and true understanding of nature and its natural laws. Or, in the words of Hume himself, "...no testimony is sufficient to establish a miracle, unless the testimony be of such a kind, that its falsehood would be more miraculous, than the fact, which it endeavors to establish..." (Hume, 1985, p. 32). Hume's argument has never been refuted, and it destroyed the traditional rationalist argument for the truth of Christianity. Theologians abandoned reasoned defenses of the supernatural, and turned instead to natural theology and arguments from design--which Hume also criticized but did not completely discredit. This was left to Darwin, and following him, all that was left to apologists is the argument to faith, or fideism, which cannot be refuted by the methods of critical inquiry or science, because it unintellectually appeals solely to the emotions. These facts make it clear that intelligent design proponents will never actually invoke the supernatural in their statements of the alleged intelligent design process and its predicted effects, because to do so they would have to abandon science and critical inquiry, things they want to keep to maintain their aura of intellectual respectability and scientific legitimacy. Since it would seem to the average person that an intelligent design theory of the universe that ultimately recognizes God as the Creator and Designer would have to involve the supernatural at some point--at least once in the beginning for deists, but much more frequently for nonbelievers in evolution--then intelligent design theorists are going to have to choose among three options: invoke natural intelligent designers (see below), abandon scientific and critical inquiry, or become metaphysical naturalists like the real scientists.
I call scientific working hypotheses metahypotheses for two reasons. First, they are indeed metaphysical and therefore not subject to easy or any verification or falsification. Their truth is as much a matter of philosophical analysis as of scientific investigation. Second, metahypotheses are above--higher than--ordinary scientific hypotheses, because ordinary scientific hypotheses and theories derived from such hypotheses make no sense unless the metahypotheses are implicitly or explicitly believed or accepted. For example, scientists would have no confidence in their scientific laws and theories unless they believed that they explained nature as it is (naturalism) and were true throughout nature (actualism). To perform the tedious work of science, scientists are motivated by the prospect of the universality of their discoveries. Specifically, if one believes that one's scientific conclusions are true except when supernatural forces contradict those conclusions, then what reason is there to perform science? Isn't it ironic that theistic scientists and other supernaturalists feel that naturalism should only be temporarily adopted in its methodological form, when it is now at least as reliable as everything else in science? If they reject naturalism, what is their rationale for believing anything scientific? They could just as reasonably reject it all.
Of the various metahypotheses of science that have been overwhelmingly corroborated over the centuries, certainly one of the most important is naturalism itself. This is undoubtedly a metaphysics, but it has been examined, tested, and repeatedly corroborated by empirical, rational, and skeptical methods. While naturalism is in principle and in fact unfalsifiable, it is nevertheless the most reasonable ontology, because it's reliability has been justified by those reliable methods. Furthermore, while science as a process only requires the adoption of methodological naturalism, I think that the adoption of methodological naturalism by scientists and others logically and morally entails ontological naturalism. Although I certainly recognize the possibility and practicality of decoupling methodological and ontological naturalism, I believe assuming the truth of naturalism only for the purpose of practicing or believing in science is a logical error and moral mistake. I would grant robots the status of being solely methodologically naturalistic, with no necessary commitment to ontological naturalism and no concomitant logical and moral error--and since according to Daniel Dennett (1996) we humans are all robots anyway, theistic methodological naturalism may be okay after all!
Naturalism versus Supernaturalism in Science
We now turn to the other major topic of this paper, the claim by scientific creationists, theologians, and philosophers who believe in theism and metaphysical supernaturalism that (1) supernaturalistic explanations are preferable to some scientific naturalistic explanations, particularly concerning questions of origins, and that (2) scientists can and should explain some natural phenomena by using supernaturalistic hypotheses within science (Thaxton, Bradley, and Olsen, 1984; Geisler and Anderson, 1987; Johnson, 1990, 1991, 1994a, 1994b, 1995; Davis and Kenyon, 1993; Moreland, 1994; Behe, 1996). Although, on their face, these suggestions sound preposterous (and I think they are preposterous), nevertheless they are serious suggestions from authors who are able to make their cases with greater or lesser cogency, so they deserves a serious analysis and refutation, which I can only initiate here in a somewhat general way.
The writers cited above have produced books that are different in many respects from the grossly pseudoscientific, intellectually incompetent genre best exemplified by books from the Institute for Creation Research. While these titles are more intelligently written and better argued, some of the authors, to some degree, make the same specious arguments, indulge in the same misrepresentations of scientific information and misunderstandings of scientists and their writings, do not understand or do not wish to acknowledge the now voluminous critiques published in recent years by evolutionary scientists that explicitly refute creationist arguments, and continue to promote the same contempt for evolution that creationists always have. While I cannot deal with such topics in this paper, I and others have done so in the past (references follow). Why don't creationists attack something like thermodynamic theory or the theory of plate tectonics for a change? It is no fun to have to spend time dealing with creationist literature, but the degree of understanding of science among the public is so small that many people can be and are fooled by creationist arguments, so someone who understands the issues needs to deal with it.
I view the method of critical inquiry (= critical thinking, scientific thinking, scientific method) as the most reliable method of discovering truthful knowledge in any discipline, especially including science and philosophy. Critical inquiry is the best truth-seeking, problem-solving method humans have to examine scientific hypotheses and theories, evaluate competing truth claims, or establish the validity of a philosophy or philosophical position (I used it superficially earlier to demonstrate the validity of naturalism). Along with Susan Haack (1996), I believe that truth matters in epistemology, and we should understand what it means to claim to know truth. The truth that critical inquiry produces is called reliable knowledge, knowledge that has a high probability of being true because it has been justified by a reliable method that uses empiricism, rationalism, and skepticism. Without going into a lengthy analysis here of an understanding of critical inquiry that I and many other scientists and philosophers have shared for years, let me just refer readers to a recent book that exemplifies this method: The New Skepticism: Inquiry and Reliable Knowledge, by Paul Kurtz (1992). While the use of empiricism and rationalism in science and philosophical inquiry have been around for years (centuries), participants in the modern skeptics movement, including myself, have increasingly emphasized the skeptical (tentative, fallibilist) aspects of critical inquiry, and the book by Kurtz presents a good summary of these ideas.
It is refreshing to state that, unlike theistic methodological naturalists, theistic metaphysical supernaturalists who promote supernaturalism within science or instead of science engage in no logical or moral errors in support of their beliefs: they unequivocally and explicitly support the action of supernaturalism in both nature and supernature. What they wish to practice and promote, however, is not science, but pseudoscience. Science, as I hoped everyone understood by now, requires at least methodological naturalism; supernatural explanations, therefore, are illegitimate. Perhaps I should clarify this issue.
The boundary between science and pseudoscience is a problem for the philosophy of science, termed the "demarcation problem." The argument is as follows: there is a continuum from normal science to frontier science, fringe science, and pseudoscience, and the boundary between legitimate science and pseudoscience is not clearly known or defined. I acknowledge and accept this problem of demarcation (I am familiar with the work of Larry Laudan and other philosophers of science who explicitly discuss this problem; Laudan's articles are reprinted in Ruse, 1996a). I have sometimes wondered how Michael Ruse would have testified about scientific method before Judge William Overton if the topic had been the constitutionality of state legislation passed to ensure fair and balanced treatment for "punctuated equilibria along with the prevailing theory of phyletic gradualism," or for "cold fusion along with the universally-accepted theory of thermodynamics," or for "extrasensory perception along with the prevailing view of its absence within psychology." All three of these examples are legitimate demarcation problems between science and pseudoscience, falling as they do among the categories of frontier and fringe science.
But I maintain that there is at least one criterion of legitimate science that correctly identifies scientific creationism and all forms of supernatural explanation in science as pseudoscience. This is the criterion of testability. It dates from the beginning of the nineteenth century when scientists began to explicitly eschew supernatural explanations, and it was quickly recognized and identified in the work of the first philosopher of science, John Herschel, who is responsible for first explicating the hypothetico-deductive method of science. It is now commonly accepted, for example, that Charles Darwin deliberately used Herschel's characterization of correct scientific method in his effort to establish the fact and his theory of evolution in 1859 (Ghiselin, 1969). In the twentieth century, Karl Popper championed and extended this same idea in his work on prediction, deduction, testing, and falsification in science. I am completely aware that Popper's solution to the demarcation problem is incomplete. (How would one apply it in the continuing controversy over the reality of ESP, for example, when it is the very predictions, tests, and statistical degree of falsification that is under controversy?) I maintain, however, that the criterion of testability or falsifiability is a necessary but not sufficient solution to the demarcation problem, and while I admit it cannot distinguish science from pseudoscience in all areas of interest, the "necessity of being susceptible to falsification" criterion is quite capable of eliminating all supernatural explanations, such as creationism and intelligent design, from legitimate science--because such explanations cannot be falsified.
Pseudoscience is false science, an ideology masquerading as science. Often the ideology is religious, as is the case with Christian fundamentalism, but sometimes it is political, such as is the case with Lysenkoism. There is a very fine line between religious and political ideologies, and each adopts many of the characteristics of the other. For example, scientific creationism can easily be considered a political movement, seeking, as it does, to gain intellectual respectability by holding conferences at respected secular universities and gain access to public school textbooks and classrooms through legislative efforts and the courts. For its case, Lysenkoism had the status of a cult within the religion of Soviet state communism. Pseudosciences cannot be falsified because they claim supernatural, preternatural, and paranormal elements exist and that these interact with the natural world, and the existence of these elements and the nature of their interactions with the natural world cannot be investigated and tested by the naturalistic methods of science.
There are many other criteria that prove scientific creationism to be a pseudoscience, such as its advocates failure to publish their work in the standard scientific literature, their misrepresentation of scientific information, their use of specious and fallacious arguments, their continued ignoring or disbelieving of scientific refutations of their claims, their flagrant mistakes, untruths, quotes out of context, and so forth (see Kitcher, 1982; Ruse, 1982; Futuyma, 1982; and Godfrey, 1983, which contains my own contribution, Schafersman, 1983; for Johnson's Darwin on Trial, see Scott and Sager, 1993, and Scott, 1993; for many creationist books, see NCSE, 1994). Goals of creationist pseudoscience are to subvert legitimate science in courts, legislatures, and school boards, to confuse the public about the methods and powers of science, and especially to derogate the heroic accomplishments of science that overwhelmingly demonstrate the truth of evolution (such as the finches of the Galapagos Islands (Weiner, 1994), the cichlid fish in Lake Victoria (Goldschmidt, 1996), the fruit flies of the Hawaiian Islands, the whale, horse, reptile-to-mammal, hominid-to-human transitional sequences in the fossil record, Cambrian fossils (Gould, 1990), etc.). These efforts are not only morally reprehensible, they are dangerous in an age when viruses, bacteria, and insects are evolving rapidly due to human selection pressures--microbes may once again become the primary agent of human population control.
For the purposes of this paper, however, I am only considering the failure of creationists to present a scientifically-acceptable theory of creation, which I claim they have not done because it is impossible for them to do so within legitimate science. Their solution to their very real, implicitly recognized, problem is to attempt to change the definition of science to allow supernatural explanations. This reveals, I hope, the tremendous irony of the current attempts by creationist and supernaturalistic philosophers to change the nature of science by forcing it to accept supernatural elements. The current effort is the implicit admission by creationists that scientific creationism or intelligent design requires supernatural explanations and that scientific creationism is not now part of science. For the current effort would not have to be made if either (1) scientific creationism did not require supernaturalism or (2) scientific creationism was currently part of science. For decades, scientific creationists have claimed that their ideology was scientific, and they have tried to force their doctrine into public schools by the rationale that it is as scientific as evolutionary science. Scientists have repeatedly disputed these claims; now, with their current efforts to create a supernaturalistic science, the creationists implicitly agree with us!
The scientific creationist political effort to have people believe that supernatural religious beliefs are scientific is prompted by science's great intellectual legitimacy and prestige, brought about by its tremendous success. People will naturally be attracted to such a knowledge system and thus be exposed to its associated philosophy of methodological naturalism and the metaphysical consequences. Scientific creationism is a religio-political effort that tries to subvert science, to create a misunderstanding in people's minds about the true nature of science. Scientific creationists accomplish this by confusing people about how science works, the scientific method, the nature of scientific evidence, reasoning, and skepticism, and the overwhelming evidence for evolution. Assaults on science textbooks, debates with scientists, creationist seminars and presentations, and most spectacularly, the attempts to pass balanced treatment laws--all are aimed at reducing scientific literacy among the lay public by promoting pseudoscience.
Scientific creationists in particular and scientific supernaturalists in general claim, of course, that the new supernaturalistic science they propose does make predictive supernatural explanations based on good evidence, that these explanations are legitimate scientific hypotheses that can be tested and falsified, and therefore the conclusions they reach that invoke the supernatural can and should be considered legitimately scientific. This is the primary thesis of the books cited above, and the explicit thesis in some of them, such as Moreland (1994). I strongly disagree with this claim. Contrary to Larry Laudan, I do not consider scientific creationism to be merely "bad science"; parapsychology, cold fusion, and many other topics are bad science--creationism is pseudoscience.
Larry Laudan (three papers reprinted in Ruse, 1996a) has contempt for the testability criterion, claiming that many pseudosciences would be scientific under this criterion because they are, in principle, falsifiable, and their claims have been falsified. He puts scientific creationism in this category. I am not sure if Laudan is as familiar with the creationist literature as Michael Ruse and I, but he is wrong. I agree with Laudan that when pseudosciences like scientific creationism make statements about the natural realm, such as a 6000-year old Earth or a specific fossil sequence, the predictions are easily falsified. This is also true for the many other pseudosciences that Laudan identifies. If they restricted their predictive "hypotheses" to the natural realm, used valid arguments, accepted empirical evidence to the contrary as valid, and agreed that they would change their views if conflicting evidence was present, all of these pseudosciences would long ago have disappeared because they would have been falsified. The reason they haven't vanished is because their proponents invariably make claims that have supernatural, preternatural, and paranormal elements, and these elements cannot be tested and falsified, so pseudosciences can persist just as Popper claimed (but then he once thought that modern scientific evolutionary theory was unfalsifiable, so what does he know?).
Michael Ruse (1996b) uses a similar argument is his reply to Laudan; he quotes Duane Gish (1979) and Henry Morris (1966) to the effect that the Creator used processes that "are not now operating anywhere in the natural universe," that we "cannot discover by scientific investigations anything about the creative processes used by the Creator," and "it is...quite impossible to determine anything about Creation through a study of present processes..." I certainly agree with these refreshingly candid, clear, but old statements; times change, and now the authors of The Creation Hypothesis and Of Pandas and People insist that we can use the intelligent design hypothesis in science.
The Three Societies Argument
Supernatural creation requires a supernatural creator. Does the intelligent design hypothesis require a supernatural creator? Yes and no! One can construct an argument for intelligent design as follows: There are many animal societies on Earth that exist on a continuum from very simple to highly complex. Flatworm society is simple and human society is complex. If flatworms had a science, they would comprehend humans as superflatworms--as Unseen Watchers, creators of microscopes and petri dishes, despoilers of meadow ponds, givers of life and agents of death: able to snatch any flatworm from its pond and take it to flatworm heaven. Perhaps they imagine that a human looks like a flatworm, but one with superflatworm powers: transformer and manipulator of matter and energy, possessing seemingly instantaneous abilities of transport, all-powerful, all-knowing, probably all-good, since flatworms would project their highest moral understandings onto their Human, and any Human-caused injury to flatworm society (such as draining a pond) is all part of an ineffable plan. Flatworms would probably consider their Human to be above flatworm nature, that is, supernatural from their point of view.
Now, let's consider a third society, one greater and more powerful than human society to the same extent that human society is greater than flatworm society. This third society consists of extraterrestrial aliens living somewhere in the universe. The product of billions of years of biological evolution, just as with humans, but also millions of years of cultural evolution and scientific accomplishment greater than humans. Their name is the Dogon. The Dogon aliens have such an advanced technology that they have mastered the creation, transformation, and manipulation of matter and energy at any magnitude. They can create and move stars and planets, or destroy them. Creating living organisms from lifeless molecules is easy for them. They have even seeded simple life forms on suitable nearby planets and are studying the results, although they are completely aware that it will take billions of years for anything really interesting to evolve. The Dogon technology allows them to instantaneously travel throughout the universe, but the universe is so large that they have only explored a very tiny portion of it. They have found no other intelligent life forms in the universe, since they haven't yet visited Earth or even its galaxy, the Milky Way. While they have found living organisms on many other planets, not a single one has animals that have developed a technology.
An important aphorism states that, "Any sufficiently advanced technology is indistinguishable from magic." I revise this as follows: "Any sufficiently advanced technology is indistinguishable from miracles." Magic is illusion, deception, and we are considering the real thing here. The Dogon are obviously superhuman; their technology allows them to perform miracles from a human perspective: they can levitate, turn chemicals into life, revive dead organisms with their medicine, instantaneously transport themselves through time and space, transform matter and energy into any form, extend their minds by extrasensory perception--in short, they are all-powerful and all-knowing by human standards. In addition, they long ago discovered the advantages of removing evil from their society, so they are also all-good.
How would the Dogon appear to us? They are unquestionably Intelligent Designers. They are completely natural, and if we knew something about them, we could legitimately specify their activities in our scientific theories about nature. In fact, we would be obligated to, as obviously would flatworms about humans in flatworm scientific theories. If flatworms were conscious, they would have to be aware of humans--how could they miss us? Humans would pervade their scientific understanding of nature. If the Dogon existed and we were aware of them, the same would be true of our scientific understanding of nature. We would be obligated to hypothesize at least one Intelligent Designer--maybe more. That's the wonderful thing about the intelligent design hypothesis--you don't have to stop at one. There could be many Intelligent Designers. And, since some of the Dogon are not as thoughtful or careful as others, one can hypothesize an Unintelligent Designer (perhaps it was this Dogon who designed the close proximity of human reproductive organs to the systems that eliminate metabolic wastes).
If we knew of the Dogon aliens, we could explain so much. The possibilities would be endless for scientifically legitimate naturalistic explanations involving an intelligent designer. So why don't scientists use intelligent design explanations. Because we know of no Dogon. There is no empirical evidence for them, and no reason to believe in them despite the lack of evidence. Naturalistic explanations do an excellent job of explaining a great deal about nature, including the presence in our bodies of a sewage disposal pipeline in the middle of a major recreational area. Scientists don't use supernaturalistic/intelligent design explanations because naturalistic explanations have been so successful, and we have confidence that they will continue to be successful in those frontier areas that currently have no really good, widely-accepted theories, such as origin of life and origin of universe questions.
I am aware of the argument put forward by proponents of intelligent design that says the following: if evolutionary scientists can legitimately use arguments of unintelligent design (human body inadequacies and imperfections, such as lower back pain from upright posture, position of the larynx and esophagus, propensity of cardiac arteries to accumulate fat deposits, vestigial organs, structure of the eye, etc.; Rube Goldberg devices in nature, such as the panda's thumb, the rotated eye of flatfish, etc.) to refute creationism and thereby support evolution, then creationist scientists should be able to legitimately use intelligent design arguments to support the existence of an intelligent designer--whom they usually equate with a creator--and cast doubt on evolution. Although this argument appears to be convincing, like most creationist arguments it breaks down when carefully examined.
Unintelligent-design arguments (also called arguments from imperfection or imperfect design) were legitimate in science during the nineteenth century when the creation hypothesis was still a viable option in biology; Darwin used some in the Origin, for example. As evolution became quickly accepted, design arguments disappeared in science because they became unnecessary. They are offered today by scientists in a specific context: popular science writing addressed to individuals who still are unaware of the overwhelming evidence for evolution and who still may believe in creationism and intelligent design. No scientist today would think of using an unintelligent design argument in a formal scientific paper in a legitimate scientific journal, that is, in the primary literature. Such design arguments are only found in the secondary literature of popular science essays and books for nonspecialists. Their sole purpose is to remind readers--who often do not really understand evolutionary theory--that seemingly compelling arguments from intelligent design can be refuted easily by counter examples. Furthermore, such imperfect-design arguments are not meant literally--no real unintelligent designer is hypothesized to exist--for the appearance of design in nature is explained as adaptation due to evolution by natural selection, a mechanistic but deterministic natural process working on organic variability, that is, not as design at all, but merely the appearance of design. Finally, as discussed above, if we had a reason to suppose the existence of a purely natural creator or intelligent designer, we could legitimately use such arguments in science, but we do not, since no such reason exists, not to mention the fact that no evidence exists for such a designer. I maintain, therefore, that intelligent design arguments assuming a supernatural creator or intelligent designer are today invalid in science, as they have been since the late nineteenth century, because they are not necessary and because they cannot be tested.
There is no way for supernaturalists to establish the truth of an intelligent design hypothesis using the methods of science. I maintain that it is impossible, in principle, for natural evidence and arguments to demonstrate the existence of anything supernatural, such as creation, intelligent design, or a god. In order to demonstrate the reality of such supernatural processes or entities in this way, one would have to know the relationships or interactions between the natural and supernatural, and we don't know these (or we would have to be able to control most of the supposed relationships or interactions, to discover the one we don't know, but we can't control these). Furthermore, by the methods of science, we can't know these relationships anymore than we can know the supernatural elements. Attempts at explaining these relationships have included natural theology (classical arguments from design) and the anthropic cosmological principle, neither of which has been successful. Modern attempts using intelligent design or creation hypotheses will likewise fail, because in essence these are all god-of-the-gaps explanations, attempts to use God or an Intelligent Designer to explain current natural mysteries that seemingly have science stumped, such as the origin of life, the origin of the universe, the origin of phyla in the Cambrian, and so forth. When natural scientists succeed in solving any natural mystery or problem, that gap vanishes and the available room for the intelligent designer becomes smaller. Simple lack of knowledge for some natural process or event is not sufficient to justify a supernatural explanation. Frankly, I consider these god-of-the-gaps intelligent design arguments to be unworthy of modern analysis. So the use of natural evidence and arguments to demonstrate the existence of the supernatural is not sound.
A major problem for intelligent creation and design advocates is that before they can use the hypothesis of a creator or intelligent designer in their hypotheses, they must first demonstrate its existence. Premises of logical arguments, which is of course what predictive scientific hypotheses are, must be true if the conclusion is to be true. The terms "creator" and "intelligent designer" are currently as devoid of comprehensibility as the term "god." Before these terms can be used in scientific hypothetical premises, they must first be found in a conclusion that does not assume their existence. But no one has ever produced such a valid argument, either scientifically or logically. Since I argued in the previous paragraph that natural, scientific evidence could not be expected to demonstrate the existence of a supernatural creator or intelligent designer, I see no alternative but to use logical, rational arguments to do this. There are ontological arguments that purport to establish the existence of God (Plantinga, 1967; but see Oppy, 1996, for a refutation), and I see these arguments as superior to natural ones, such as design or cosmological arguments, but not thereby more convincing.
The problem of "origins" is the main area that creationists and intelligent design proponents see as the difficulty for naturalistic science. Perhaps 90% of science does not deal with the "origin" of something, and presumably creationists would not find this major part of science objectionable; this may explain, for example, the lack of creationist activity in criticizing plate tectonic theory or relativity theory. Efforts were made (Thaxton et al., 1984; Geisler and Anderson, 1987) to identify two different kinds of science, "operations science" and "origins science." The distinction that these authors make deals with natural phenomena that occur "with regularity" and those that occur "singularly." Regularly-occurring phenomena can be studied by operations science, essentially the normal, legitimate science we have today. But singular phenomena, such as the origin of species, of life, the Earth, the solar system, the galaxy, and the universe, can only be studied by origins science. Furthermore, these authors maintain that there are also two different causes in operation in nature, primary causes and secondary causes. Thaxton et al. (1984) explicitly identify the primary cause as the "God hypothesis," and while agreeing that using this primary cause in operations science is not permissible, in origins science it is not only permissible, but essential, since God would have willed many singular natural effects using supernatural causes, i.e., miracles.
Needless to say, this two-faced science is a false dichotomy: there is no split in science between singular and repeatable phenomena. There are a number of reasons for this, but basically it boils down to the following: all phenomena in nature are singular, and all are repeatable. The component parts or steps of a repeating or regular phenomenon can be examined as if each was a singular event (such as the movements of electrons between shells of different energies), and every singular event is merely an example of a class of singular events that are essentially identical (such as a speciation or origin of life event). The only exception to this refutation is, of course, the singular origin of the universe. We believe we understand how the universe formed--by the explosion of a singularity (black hole) and subsequent expansion--but we have no idea what the singularity was doing there in the first place, and we may never know. Why is there something rather than nothing? We don't know. The Big Bang created time and space as well as matter and energy, so there was no "before" before the explosion of the singularity, and this timeless state (there is no intelligible or real "there" or "first place" for the singularity to be "there in the first place"!) is certainly a great mystery. But we need not indulge in supernaturalism to solve it. It is manifestly possible to live with some uncertainty or ambiguity about existence, and not grasp at ineffable solutions that only really increase our uncertainty and ambiguity, not reduce it.
Scientific hypotheses must contain a cause and effect relationship within their predictive explanations. Testing the explanatory predictive hypothesis requires understanding the hypothesis and understanding (or controlling) the steps between the cause and the effect. Invoking a supernatural intelligent designer destroys the cause and effect relationship of any deductive scientific hypothesis, preventing us from understanding the hypothesis, and thus disallowing it as really explanatory. So, I would accept the hypothesis of a purely natural creator/intelligent designer--such as the Dogon--if one was necessary, but as Laplace would say, I have no need for that hypothesis. As for the hypothesis of a supernatural creator/intelligent designer, I have no need for that hypothesis either.
Verachte nur Vernunft und Wissenschaft,
des Menschen allerhöchste Kraft,
laß nur in Blend- und Zauberwerken
dich von dem Lügengeist bestärken,
so hab' ich dich schon unbedingt.
These wonderful lines from Faust, Part 1, lines 1851-1855, express Johann Wolfgang von Goethe's view of human reason and science, and the consequence of their abandonment by proponents of superstition. The excerpt has been translated in a variety of ways. Walter Kaufmann (1961, p. 195) gives it in a rhyming translation as follows:
Have but contempt for reason and for science,
Man's noblest force spurn with defiance,
Subscribe to magic and illusion,
The Lord of Lies aids your confusion,
And, pact or no, I hold you tight.
Carlyle F. MacIntyre also prefers a rhyming translation:
Scoff at all knowledge and despise
reason and science, those flowers of mankind,
Let the father of all lies
with dazzling necromancy make you blind,
then I'll have you unconditionally.
Stuart Atkins (1994, p.47), in a literal and non-rhyming translation, has it as follows:
Scorn learning, if you must, and reason,
the highest faculty mankind possesses,
let your fondness for self-deception
involve you deeper still in magic and illusion,
and its dead certain you'll be mine!
My own translation is completely naturalistic. Goethe, no supernaturalist, used the word geist in Faust in a variety of ways, referring not just to spirit or transcendent being, but also to human psyche or psychological condition (i.e., spirit in a purely materialist sense). Self-deception is therefore an excellent translation of Lügengeist, "lying spirit," meaning Mephistopheles himself in a literal context, but symbolically much more. Mephisto is the supreme geist of the drama, both the personification and abetter of that "lying spirit" within humans, the "spirit" of self-deception--that is, of uncomprehended and unacknowledged ignorance and misunderstanding--the bane of human happiness, self-actualization, and civilization. (Faust, for example, despite his wisdom and learning, is himself a victim of self-deception: this is one of the major themes of the story. Goethe's point, of course, is that despite humanity's wisdom and learning, we are and will always be victims of self-deception if we despise or ignore reason and science. It is our nature to deceive ourselves: this must be one of the great lessons of science, literature, and history!)
I translate the lines as follows:
Despise reason and science,
humanity's greatest powers,
indulge in illusions and magical practices
that reinforce your self-deception,
and you will be unconditionally lost!
 I can't say "certainly no," as much as I would wish to, for I must be agnostic about the supernatural. Just because I have no knowledge of it's existence doesn't mean it does not exist. Nonbelief does not necessarily entail denial. Supernature may be real without empirical evidence or logical reason, and we may just be unaware of its reality. But I don't believe in the supernatural, so I am also an asupernaturalist (or nonsupernaturalist). The reason for this nonbelief is a simple application of critical thinking: there is no empirical evidence for the supernatural and no reason to believe it exists despite the lack of evidence, so skepticism demands that one not believe in it.
The same arguments hold true for theism. A common misunderstanding is that agnosticism is an intermediate position between theism and atheism, but this is quite mistaken. Atheism and agnosticism are not mutually exclusive. Atheism is the simple nonbelief in a god; the term for believing that a god does not exist, and for stating that a god does not exist, is antitheism. I personally know many of the most eminent atheists on this planet, and not one of them claims that a god does not exist; they are agnostic on that subject. Atheists may be antitheistic about specific gods, such as Allah, Jehovah, and the Christian Trinitarian God, but never about the possibility of a god in general--here we are agnostic. Many less well-informed atheists today prefer (and many famous historical atheists, such as Thomas Henry Huxley and Robert Ingersoll, preferred) to be called "agnostic" instead of "atheist" because of the well-known pejorative association of being known as an atheist; perhaps, as a self-descriptor, they might consider the synonymous term "nontheist," which doesn't sound so bad. (Use of the word "atheism" as simple nonbelief in a god has been the uniform understanding within freethought for centuries; other definitions, such as those equating atheism with denial of God's or a god's existence, have been forced upon atheists by theists as a rhetorical device to confuse what must be demonstrated and by whom, in order to strengthen the theist position.)
 So willing is Eugenie Scott to protect theistic supporters of evolution, that she quite unjustly rebukes Douglas Futuyma and George Gaylord Simpson for making over-generalizations about reality and presenting their metaphysical philosophies in the guise of science. She writes (Scott, 1996, p. 519):
To further defuse the religious issue, scientists can be more careful about how they use terms. For example, evolutionists sometimes confuse the evidence we have for considerable contingency during the course of evolution with evidence for a lack of ultimate purpose in the universe. Futuyma  writes,Perhaps most importantly, if the world and its creatures developed purely by material, physical forces, it could not have been designed and has no purpose or goal....Some shrink from the conclusion that the human species was not designed, has no purpose, and is the product of more material mechanisms--but this seems to be the message of evolution.
G. [G.] Simpson  is regularly quoted with dismay by creationists as saying "Man is the result of a purposeless and natural process that did not have him in mind. He was not planned." A theist might respond that we do not know what God's purpose is or what [H]e planned. It is possible that if there is a...deity, it was part of its plan to bring humans and every other species about [by evolution]. Of course, this would be a theological statement, but that, indeed, is the point. Saying that "there is no purpose in life" is not a scientific statement. We are able to explain the world and its creatures using materialist, physical processes, but to claim that this then requires us to conclude that there is no purpose in nature steps beyond science into philosophy.... [I]n my opinion, for a nonreligious [Scott means someone who is a metaphysical naturalist] professor to interject his own philosophy into the classroom in this manner is as offensive as it would be for a fundamentalist professor to pass off his philosophy as science.
It should be obvious that Eugenie Scott is confusing categories here. The statements of Futuyma and Simpson are completely correct and scientifically accurate: there is no purpose in nature, and humans were not planned or designed in the course of their evolution. (We are all intentionally ignoring human purpose, of course). This is one of the supreme discoveries of science, and for Scott to suggest that scientists engage in self-censorship to protect the religious sensibilities of theistic methodological naturalists (evolution's most numerous supporters and scientific creationism's greatest enemy) is authoritarian and moralistic. Neither author above said or knows whether there is a supernatural purpose: they were both speaking from a completely scientific and therefore naturalistic point of view. They would not deny that there might be a supernatural purpose. I am sure they would say that if supernaturalists want to believe there is such a supernatural purpose, let them believe it, but don't try to say that such a purpose exists in nature--it doesn't, as science has revealed beyond all doubt. Simpson and Futuyma are obviously ontological naturalists, but they were not trying to pass off their philosophy as science. They were only speaking about what science knows about nature, and everything they say in the quotations above is completely correct and proper. In other words, it is not "philosophy" to say there is no purpose in nature: this is a scientific fact. The worst they are guilty of is promoting methodological naturalism, but I don't see how any scientist, even theistic ones, can avoid promoting this.
There is another, more subtle, error in Scott's remarks that I cannot pass over. I am sure that both Futuyma and Simpson know about contingency in evolution and did not confuse contingency with the "lack of ultimate purpose in the universe." The lack of cosmic purpose in nature does not depend solely on the fact of evolutionary contingency. Simpson, as a matter of fact, was the first author to explicitly identify and discuss the evolutionary implications of contingency (1964, 1967); he was the originator of this concept. Subsequently, Ernst Mayr discussed this also (Mayr, 1985), and today we know about this important element of evolutionary theory from the writings of, for example, Stephen Jay Gould in his book Wonderful Life (1990).
Atkins, Stuart, editor and translator, 1994, Faust I & II, Vol. 2 of Goethe: The Collected Works, Princeton University Press.
Audi, Robert, 1996, "Naturalism," in The Encyclopedia of Philosophy Supplement, Donald M. Borchert, editor in chief, Macmillan Reference USA, p. 372-374.
Behe, Michael J., 1996, Darwin's Black Box: The Biochemical Challenge to Evolution, The Free Press.
Buell, Jon, and Virginia Hearn, editors, 1994, Darwinism: Science or Philosophy, Foundation for Thought and Ethics.
Callebaut, Werner, 1993, Taking the Naturalistic Turn, or How Real Philosophy of Science is Done, University of Chicago Press.
Danto, Arthur C., 1967, "Naturalism," in The Encyclopedia of Philosophy, Paul Edwords, editor in chief, The Macmillan Co. and The Free Press, New York, p. 448-450.
Davis, Percival, and Dean Kenyon, 1993, Of Pandas and People: The Central Question of Biological Origins, Second Edition, Haughton Publishing Co.
Dennett, Daniel C., 1991, Consciousness Explained, Little, Brown.
Dennett, Daniel C., 1996, Kinds of Minds: Toward an Understanding of Consciousness, BasicBooks.
French, Peter A., Theodore E. Uehling, Jr., and Howard K. Wettstein, 1994, Midwest Studies in Philosophy, Volume 19: Philosophical Naturalism, University of Notre Dame Press.
Futuyma, Douglas J., 1982, Science on Trial: The Case for Evolution, Pantheon Books (1995, Sinauer Associates, Inc.)
Geisler, Norman L., and J. Kerby Anderson, 1987, Origin Science: A Proposal for the Creation-Evolution Controversy, Baker Book House.
Ghiselin, Michael T., 1969, The Triumph of the Darwinian Method, University of California Press (1984, University of Chicago Press).
Gish, Duane, 1979, Evolution: The Fossils Say No!, Third Edition, Creation Life Publishers.
Godfrey, Laurie, editor, 1983, Scientists Confront Creationism, W. W. Norton & Co.
Goldschmidt, Tijs, 1996, Darwin's Dreampond, The MIT Press.
Gould, Stephen Jay, 1990, Wonderful Life: The Burgess Shale and the Nature of History, W. W. Norton & Co.
Grinnell, Frederick, 1994, "Radical Intersubjectivity: Why Naturalism Is an Assumption Necessary for Doing Science," in Buell and Hearn, p. 99-106.
Gross, Paul R., and Norman Levitt, 1994, Higher Superstition: The Academic Left and its Quarrels with Science, The Johns Hopkins University Press.
Gross, Paul R., Norman Levitt, and Martin W. Lewis, editors, 1996, The Flight From Science and Reason, The New York Academy of Sciences.
Haack, Susan, 1996, "Concern For Truth: What It Means, Why It Matters," in Gross, Levitt, and Lewis, p. 57-63.
Hull, David L., 1988, Science as a Process: An Evolutionary Account of the Social and Conceptual Development of Science, University of Chicago Press.
Johnson, Phillip E., 1990, "Evolution as Dogma: The Establishment of Naturalism," p. 1-17, Foundation for Thought and Ethics special publication, Haughton Publishing Co.
Johnson, Phillip E., 1991, Darwin on Trial, InterVarsity Press.
Johnson, Phillip E., 1994a, "Darwinism's Rules of Reasoning," in Buell and Hearn, p. 6-20.
Johnson, Phillip E., 1994b, "Darwinism and Theism," in Buell and Hearn, p. 42-49.
Johnson, Phillip E., 1995, Reason in the Balance, InterVarsity Press.
Kaufmann, Walter, translator, 1961, Goethe's Faust, Doubleday & Co.
Kitcher, Philip, 1982, Abusing Science: The Case Against Creationism, MIT Press.
Kitcher, Philip, 1992, "The Naturalists Return," Philosophical Review, vol. 101, p. 53-114.
Kitcher, Philip, 1993, The Advancement of Science, Oxford University Press.
Kurtz, Paul, 1990, Philosophical Essays in Pragmatic Naturalism, Prometheus Books.
Kurtz, Paul, 1992, The New Skepticism: Inquiry and Reliable Knowledge, Prometheus Books.
Lacey, Alan R., 1995, "Naturalism," in The Oxford Companion to Philosophy, Ted Honderich, editor, p. 604-606, Oxford University Press.
Luntley, Michael, 1995, Reason, Truth and Self: The Postmodern Considered, Routledge.
Mayr, Ernst, 1985, "The Probability of Extraterrestrial Intelligent Life," in Extraterrestrials: Science and Alien Intelligence, E. Regis, Jr., ed., Cambridge University Press, p. 23-30; reprinted in Toward a New Philosophy of Biology: Observations of an Evolutionist, 1988, The Belknap Press of Harvard University, p. 67-74.
Moreland, J. P., 1994, The Creation Hypothesis, Scientific Evidence for an Intelligent Designer, InterVarsity Press.
Morris, Henry M., 1966, Studies in the Bible and Science, Presbyterian and Reformed Publishing Co.
NCSE, 1994, Reviews of Creationist Books, National Center for Science Education.
Nielsen, Kai, 1996, Naturalism Without Foundations, Prometheus Books.
Oppy, Graham, 1996, Ontological Arguments and Belief in God, Cambridge University Press.
Papineau, David, 1993, Philosophical Naturalism, Blackwell.
Plantinga, Alvin, 1967, God and Other Minds: A Study of the Rational Justification of Belief in God, Cornell University Press.
Post, John F., 1995, "Naturalism," in The Cambridge Dictionary of Philosophy, Robert Audi, editor, p. 517-518, Cambridge University Press.
Ryder, John, 1994, American Philosophic Naturalism in the Twentieth Century, Prometheus Books.
Ruse, Michael, 1982, Darwinism Defended: A Guide to the Evolution Controversies, Addison-Wesley.
Ruse, Michael, 1986, Taking Darwin Seriously: A Naturalistic Approach to Philosophy, Blackwell.
Ruse, Michael, editor, 1996a, But Is It Science: The Philosophical Question in the Creation/Evolution Controversy, Prometheus Books.
Ruse, Michael, 1996b, "Pro Judice," in Ruse, 1996a, p. 356-362.
Schafersman, Steven D., 1983, "Fossils, Stratigraphy, and Evolution: Consideration of a Creationist Argument," in Godfrey, p. 219-244.
Scott, Eugenie C., 1993, "Darwin Prosecuted," Review of Darwin on Trial by Phillip Johnson, Creation/Evolution, Issue 33, p. 36-47.
Scott, Eugenie C., 1996, "Creationism, Ideology, and Science," in Gross, Levitt, and Lewis, p. 505-522.
Scott, Eugenie C., and Thomas C. Sager, 1992, Review of Darwin on Trial by Phillip Johnson, Creation/Evolution, Issue 31, p. 47-56.
Simpson, George Gaylord, 1964, "The Nonprevalence of Humanoids," in This View of Life, Harcourt, Brace and World, New York.
Simpson, George Gaylord, 1967, The Meaning of Evolution, Yale University Press.
Sorell, Tom, 1991, Scientism: Philosophy and the Infatuation with Science, Routledge.
Thaxton, Charles B., Walter L. Bradley, and Roger L. Olsen, 1984, The Mystery of Life's Origin, Philosophical Library.
Weiner, Jonathan, 1994, The Beak of the Finch: A Story of Evolution in Our Time, Alfred E. Knopf.