A Philosophical Premise of 'Naturalism'?

The main objection some prominent intelligent design (ID) creationists have against evolution is that it is unjustifiably based on the philosophical underpinning of naturalism. "The Neo-Darwinian conclusion about the process of evolution is based on a premise of metaphysical naturalism: that there are no causes except matter in mindless motion." (ARN, 1996) And "The metaphysical assumptions of scientific materialism are not themselves established by scientific investigation, but rather are held a priori as unchallengeable and usually unexamined components of the 'scientific' worldview." (Johnson, 1989) This leads to the claim that evolution excludes God (Johnson, 1999), and that it is only fair to teach an alternative (intelligent design) that allows supernatural influence. This essay, however, will show that the above claims are false. Although science does make some assumptions that might be considered naturalistic in a sense, the assumptions that science is based on are not as restrictive as creationists claim. Furthermore, the proponents of intelligent design make exactly the same assumptions in their own work. Finally, we will see that the complaint about naturalism is applied unfairly to discredit only those parts of science that naturalism's critics oppose on ideological grounds.

Naturalism

We first must clarify (or try to do so) what is meant by "naturalism." Naturalism is the philosophy that states that explanations for all phenomena must be in terms of natural causes. Some usages of "materialism" are similar, and the two terms are sometimes used interchangeably. The main point that naturalism's critics object to is exclusion of the supernatural. Some people distinguish between philosophical naturalism, which states that natural causes are all there are, and methodological naturalism, which says merely that natural causes are all that is available for science to work with. In either case, the definition invites the question of what "nature" means. A complete definition would have to explain how to distinguish whether something is natural or supernatural. I have never seen that problem addressed satisfactorily, and I will not attempt to do so here. I will use the terms "nature" and "supernatural" in their usual informal senses. "Supernatural" refers to certain inexplicable or inscrutable phenomena that are traditionally given that label, and nature refers to everything else in the universe.

Naturalism gets associated with science because natural explanations have such a good track record for explaining observed phenomena. To date, natural explanations have been determined for very, very many previously unknown areas, and supernatural explanations have been determined for none. When exploring another unknown area, the possibility of a natural explanation is the way to bet. Researchers bet that way routinely, and as a result the human race has benefitted with incredible advances in medicine, agriculture, electronics, materials science, and more. Supernatural explanations, on the other hand, have led nowhere.

Indeed, many supernatural explanations are rejected not because they are supernatural but because they cannot or do not lead anywhere. It is possible to come up with any number of possible explanations for anything -- lost socks could be caused by extradimensional vortices which our observations prevent from forming; hiccups could be caused by evil spirits inside us trying to escape; stock market fluctuations could be caused by the secret manipulations of powerful extraterrestrials. Scientists reject such claims on the grounds of parsimony. All of those claims are possible, but they require adding complicated entities which there is no adequate evidence for. To make matters worse, the nature of those entities effectively prevents investigation of them, and the impossibility of investigation prevents us from learning anything new about them. We cannot conclude that any of those explanations are wrong. But from a scientific standpoint, they are worse than wrong; they are useless.

The naturalism that anti-evolutionists most object to is philosophical naturalism, which insists on natural explanations even outside science -- i.e., that "nature is all there is." Many scientists, however, do not accept philosophical naturalism either. Some are staunch believers in God or other supernaturalism, including major contributors to evolutionary theory, such as Alfred Russel Wallace, Theodosius Dobzhansky, and Ronald Fisher, and active researchers and defenders of evolution today, such as Kenneth R. Miller and Francisco J. Ayala (see also Slack, 1997). In the United States, by one poll, roughly 40% of scientists believe in an active personal God, and there are surely many more who believe in a God fitting a definition less restrictive than the one used in the poll (Larson & Witham, 1999). These scientists would hardly work to support a philosophical position that they are steadfastly opposed to. Right away, then, we see that the main complaint about naturalism is trivially untrue.

Critics of naturalism (I will call them ID advocates for short, although some other creationists make the same criticisms) still deny such obvious facts, though. One method of denial is to claim that the God that their opponents believe in doesn't count. For example: "Naturalistic evolution is consistent with the existence of 'God' only if by that term we mean no more than a first cause which retires from further activity after establishing the laws of nature and setting the natural mechanism in motion." (Johnson, 1990) To those of us who know a few evolutionary biologists personally, such assertions are beyond ludicrous. There are likely some people who believe as Johnson describes, but there are many others for whom God is a personal, ever-present force in their life. Several denominations of Christianity and other religions, including Catholics, Methodists, Presbyterians, and Jews, see no conflict between God and evolution. (NCSE, 2000) This could hardly be the case if a naturalism inherent in evolution was inimical to theistic religion.

The other common method of denial is to focus attention on the handful of scientists who do support philosophical naturalism, such as William Provine and Richard Dawkins. These scientists, however, do not speak for all of science. Indeed, no scientists do. Part of science's strength is its diversity. Since scientists of many diverse religions are studying evolution, any religious bias one scientist tries to insert into it will soon be rejected by another. Moreover, philosophers of science, who have no stake in actual theories, also scrutinize science for unwarranted assumptions. With these watchdogs, we can be confident that the theory in the end will be virtually free of religious bias. Likewise for various philosophical, political, and cultural views. Some scientists will disagree with some of the things I say below about the supernatural. But the fact remains that there are many scientists who accept supernatural views in their religion -- some who even see their religion as motivating and inspiring their science -- and who are completely accepted in the field of science. Once one understands the basic requirements of science (more on this below), this should not be surprising. Focusing only on the most materialist scientists and disregarding the rest is a propaganda ploy, not an argument.

Most scientists would admit that there will always be phenomena that have not been explained. The more we learn, the more areas of ignorance we uncover. The wise person, when looking at these unknown areas, will say simply, "I don't know." The ID advocates, on the other hand, see the unknowns as openings for the supernatural, perhaps even evidence for it. This is the god of the gaps. Many people, including religious scientists, reject the god of the gaps for purely theological reasons, reasons that have nothing to do with naturalism. For example, they see such a position as opposing a belief in a God that is active in all creation; and, as new discoveries fill the gaps in which God is placed, they see the god-of-the-gaps as undermining a reason to believe in God. (Miller, 1998; Lamoureaux, 1999) Far from denying the supernatural, they are denying that human ignorance is a basis for worship.

Spirituality expresses itself differently to different people. Some people see their God denied by the theory of evolution. Others see God in the operation of nature, inseparable from the theory of evolution; they see a need for blatantly supernatural evidence of God as effectively denying God. Others have a variety of entirely different views. This range of views exists among scientists as well as the population at large. One may fail to understand all these views, but to pretend they don't exist is the height of insensitivity. A single spiritual view will not apply to everyone, and trying to impose one will benefit nobody but the arms dealers.

A related claim is that adherence to naturalism rules out, a priori, the possibility of detecting design (SEAO, n.d.). This claim also is easily seen to be utterly false, and not just because scientists needn't adhere to naturalism. Even when assuming naturalism, detecting design is obviously possible. One example comes from Carl Sagan, who suggests that design can be inferred from a sequence of bits counting out the first few prime numbers. In fact, this is a favorite example of one of intelligent design's main advocates (Dembski, 1998a). Carl Sagan certainly didn't assume exceptions to naturalism when he proposed that indication of design. (It is worth noting that actual SETI researchers look for an entirely different kind of evidence. They aren't looking for any pattern in the signal except a narrow bandwidth, which they consider a likely indicator based on what people would do. (SETI Institute, n.d.)) Evidence could conceivably be found that points to design of biological organisms, too; for example, records from an ancient ET civilization describing their bioengineering on Earth. Detecting design is a routine part of science already; there is no reason to change existing scientific practices to make it possible.

What Science is Based On

Many people, including some scientists, misunderstand the foundations of science, believing that science assumes naturalism in some form. As noted above, though, science is based on nature, not on naturalism. To explain this more fully, we must say something about what science is and what it is based on. There is disagreement among philosophers over the exact definition of science, but for our purposes, we needn't go into such depth. We will cover only the basic philosophical assumptions that science makes and qualities of science that are generally agreed upon.

Some basic philosophical assumptions are necessary, because conclusions can't be made until you have something to make them with. Whether they realize it or not, virtually everybody makes just a few very basic philosophical assumptions; most people would call them common sense. First, we assume that our memories are not altogether faulty; in other words, that the past is (or was) real. Second, we make an assumption about the future, namely that patterns and principles that have held true in the past will probably continue. These two assumptions together may be considered the single assumption of continuity of phenomena. Most people also assume that there is an external reality, and that our senses give at least a partially accurate indication of it.

The assumption of a continuity of phenomena is used by everybody. Consider eating, for example. You need to make assumptions about the past and its applicability to the future in order to find food, even if finding food means nothing more than remembering what cupboard it is in. You need the assumptions again to decide, say, that drain cleaner hasn't suddenly become edible today. You need the assumption to decide that this thing that looks and tastes like an apple is, in fact, and apple and not an old shoe. In short, the assumption is so basic that we need it for survival.

Those basic assumptions--a memorable past, a predictable future, and an observable external reality--are the only assumptions made by science (and even the assumption of external reality is rejected by some philosophical idealists). Science makes no other assumptions. With perception and memory, we can see that there are certain regularities in the world, and with induction, we can put them to use. In short, we can learn. Science assumes only that there is a past, present, and future that we can know something about. Once we have that, the real world provides the rest.

It is worth repeating that those assumption are not limited to science. Everybody makes them. Even if they deny them with their words, they live their lives according to them. Most people make additional assumptions, but they make those basic ones, too.

Some people think that science makes additional assumptions, but it really doesn't. It has been suggested, for example, that science assumes that the laws of nature have been constant throughout time (e.g., Morris, 1994). However, that is not an assumption but a conclusion. Uniformity of natural laws is something that scientists actively test. To date, their tests show that there has been little if any change in the last six billion years, but there is some evidence (still relatively weak) that the fine structure constant has changed slightly before that (Webb et al, 1999).

The assumption of naturalism is another assumption that science gets falsely accused of. Science does not make this assumption. Science does not assume that gods are necessary, but it does not assume they are absent, either. Science does not assume that miracles occurred, but neither does it assume a priori that they never have. (Miracles and science are discussed more below). Science is in the business of testing assumptions, not adding new ones. Individual scientists may believe one way or the other, but their beliefs are not a basis for science.

All science is based on observations of nature, which leads some scientists to say that science must assume methodological naturalism (e.g. Singham, 2002). But a little investigation shows that even this is an overstatement. The observations that science is based on are natural, but that is simply because the things we call supernatural are not observable, at least not directly. Supernatural forces can, in theory, have effects that are observable. Science allows for this possibility. In fact, several scientific studies have been done to investigate phenomena that most people would consider supernatural, including the power of prayer (Benor, 1990; Byrd, 1988; Harris et al, 1999; Cha et al, 2001), divination (Randi, 1982; Enright, 1999), prophecy (Witztum et al., 1994; McKay et al., 1999; Perakh, 2000), life after death (Schwartz et al., 2001), ESP (Wiseman et al., 1996), and more. Some organizations actively encourage scientific investigation of the supernatural (JREF, 2002). Science can hardly be called naturalistic when it actively delves into the supernatural.

If a supernatural phenomenon is found to give repeatable, verifiable results, science will study it. For example, if fairies appear where they can be repeatedly observed, measured, and tested, then they will be valid objects of scientific study. Under such circumstances, though, most people would start calling the phenomenon "natural." The fairies that come to be part of normal shared experience will get labelled "natural" even if we don't yet understand how they fly, make the little sparkling lights, and turn some of the researchers into frogs. As I mentioned earlier, delimiting the supernatural is not easy.

But what about individual miracles? What about so-called supernatural events that can't be studied? Suppose, for example, an apparition of a dead relative appears and speaks to one person on one occasion, and nothing like it ever happens again. Science has a place for such phenomena as well: that place is outside science. But they are outside science because the observations cannot be verified, not because they are supernatural. Unverifiable natural events are also outside of science. When President Harrison signed the statehood proclamations admitting North Dakota and South Dakota to the United States, he purposely did not let anyone see which he signed first. The question of which state was admitted earlier is, in practice, outside of science, because no verifiable observations can be made to answer it. (However, simply being a one-time event does not place something outside of science. The observations must be repeatable, not necessarily the event being studied. Most events have observable consequences that persist long after the event. The origin of the moon, for example, can be studied scientifically because different mechanisms for its origin imply different modern-day properties such as the chemical composition of moon rocks.) To the extent that a reputed supernatural event leaves lasting evidence, the event can be studied scientifically. And again, we find science actively engages in studying such events. However, where verifiable evidence is lacking, science does not apply.

Scientists and philosophers can disagree over other defining features of science, but at least one requirement is clear. For something to qualify as science, the observations must be independently verifiable by others. Perhaps the greatest strength of science is that all its findings are subject to testing, and verifiability of the raw data is foundational to such testing. The effect of this requirement is to remove from scientific consideration subjective impressions and unevidenced phenomena. This does not imply that subjective and unevidenced phenomena aren't important, merely that they cannot be used as the basis for scientific research.

Science has never claimed to be all-encompassing. The few people who say otherwise are usually people who want the good reputation of science to apply to their own ideas outside science. Intelligent design proponents fit in this group (Dembski, 1998b). What these people want is more akin to scientism than to science. They want the reputation of science without having earned it.

The status of Intelligent Design as science has nothing whatsoever to do with its being natural or supernatural. As we have seen, simply being supernatural doesn't disqualify something from scientific study. Intelligent Design is rejected from science simply because there is no verifiable evidence to support it. Most of Intelligent Design theory is purely subjective, saying little more than "it sure looks designed to me." Only two lines of argument have even a pretense of being scientific. The first, irreducible complexity, is a God-of-the-gaps argument. Certain biological systems, it is claimed, could not have evolved, leaving design as the alternative (Behe, 1996). This argument fails first because a lack of evolution does not imply design, and second because the arguments fail to allow for several biological processes that make the evolution of irreducible complexity not only possible but expected (Muller, 1939). The second supposedly scientific argument for design is specified complexity (Dembski, 1998c). But specified complexity is also a god-of-the-gaps argument. In fact, Dembski's "explanatory filter" for detecting design is really just the god-of-the-gaps expressed as a formal flow-chart; plus, it relies on irreducible complexity for its conclusions. The ID advocates deny that their arguments are god-of-the-gaps, and Dembski's arguments in particular are dressed with lots of rhetoric and confusing and inconsistent terminology to make them look more substantive, but in the end there is nothing behind them (Wein, 2002; Van Till, 2002). Ultimately, the only time they point to actual biological evidence, it is only to ask "how?" and note that they can think of no other answer but design. Their reasons for rejecting evolution are full of holes (e.g. Miller, 1999), and they have no positive evidence at all.

The field of science owes much of its success to the fact that it does not apply to everything. In science, as in all fields, people often have opposing views. Science has a basic criterion for resolving disputes. Since the goal of science is understanding of the real world, the world itself is the ultimate arbiter for determining answers. By limiting itself to areas where data can be tested by multiple independent observers, science ensures that its disputes can eventually be resolved; where science applies, our descriptions of nature get more and more accurate. Increasing the scope of science would destroy its authority by allowing in areas that people could never trust. Furthermore, the requirement for testability acts as a safeguard against people's darker motives. Conclusions based on fraud, selfishness, wishful thinking, and attempts at political power tend to get uncovered quickly because they get tested. Finally, by leaving out subjective ideas, science serves to unify. Different people have different tastes, different moral views, different gods. As long as we apply our personal beliefs only to ourselves, it is not for anyone else to say whether or not they are wrong. And we may associate in communities of people with similar beliefs. But for a common ground with everybody else, the one thing we all have in common is the world we live in. Science represents that part of nature which is universal, applying to everyone equally. This is not to say it rules out any personal beliefs in other areas. As we have seen, it does not; it leaves personal beliefs personal. But it does show a common ground that can and often does override even the greatest differences in religion and politics.

To show the importance of science's restriction to objectively observable fields, let us briefly look at what science would be like without it. If the objection to naturalism in science applies, then it logically applies to all sciences -- indeed, to virtually all areas of human life. Demon possession once again becomes a viable alternative to organic illness; thunder gods are an alternative to meteorology; gremlins may explain engineering failures; etc. If the logic of intelligent design were applied consistently, all other fields would be every bit as questionable as evolution.

Supernaturalistic topics are innumerable -- spiritualism, reincarnation, voodoo, Valhalla, the Dreamtime, Deism, and various New Age practices, to name just a few. If objection to naturalism is used as an excuse to get intelligent design taught as an alternative, fairness and logical consistency demand that all of the above come along as well. Theological differences between and among religions would become a branch of science. In particular, the nature of the designers would become a primary research objective, just as it is in archeology, forensics, and other sciences that deal with design. Even ID advocates do not want such topics addressed as science.

To get intelligent design accepted as science, its proponents attempt to demolish the requirement of independent, objective verifiability; they want to demolish the quality that makes science worthwhile in the first place. If they have their way, the philosophies of naturalism will remain unchanged, but scientific objectivity must be destroyed, and with it, the benefits of science.

Intelligent Design in Practice

The problems with anti-naturalism look even worse when we see the actions of its practitioners.

Despite their complaints of science being naturalistic, ID advocates use that very science when it is convenient for them. A major focus of the ID movement has nothing to do with supporting design or supernaturalism at all; instead, the aim is to tear down evolution. To this end, they cite scientific authorities and claim scientific evidence. Granted, their use of science hardly counts as such because it is selective and out-of-context, but the point remains that, when it serves their interests, they make extensive use of the very tools they claim to detest.

The methods used by ID advocates concentrate heavily on propaganda. Their efforts are almost entirely devoted to writing and speaking appearances, and include also lobbying congressmen and threatening critics with lawsuits. They do no empirical investigation of their own.

And we have already seen that ID advocates oppose the logical extension of applying their position to investigating the nature of the designer and other supernatural claims. Phillip Johnson even rejects theistic evolution on the ground that it denies God "gainful employment." (Hastie, 2001) This is despite the fact that theistic evolution is itself a kind of non-naturalistic intelligent design theory!

The objection to naturalism, obviously, is not intended to advance science at all. It is intended as an opening to allow religious views to replace scientific findings, especially evolution, that some people disagree with. Since evolution is based on observations of nature, and since those observations won't go away, the critics need to discredit either nature itself or the validity of independent observation. Appeal to supernaturalism accomplishes both goals. The selectiveness in the opposition to naturalism (not to mention its supporters' own words) shows its religious nature.

Since science is supposed to be universal (and the ID advocates have not suggested changing that), bringing in one group's religious view means rejecting every other religion. If Phillip Johnson gets his way, then the many religions which are incompatible with His god will become scientifically invalid. But changes won't be limited to religion. Any subjective view could claim scientific standing, at the expense of other views, if there is enough political power to support it. And since everyone holds at least a few minority views, everyone would suffer.

Conclusion

The claims made against naturalism by its critics don't come close to holding water. Consider:

• Naturalism is not a requirement for science. Many reputable scientists already reject naturalism. They accept an active, personal God, and yet they also accept evolutionary theory and reject intelligent design theory. Some of them, in fact, are among the greatest contributors to the theory of evolution, and some are among ID's harshest critics.
• Science is not limited to the natural. The supposedly supernatural is regularly the subject of scientific investigation, including such areas as divination, the efficacy of prayer, astrology, and more.
• The fundamental assumptions of science are basic common-sense principles that ID advocates also accept.
• Science already accepts design. As science is practiced now, design is detected routinely where evidence supports it.

The intelligent design advocates feel that they are restricted by the practices of science. Duh. Those practices are what make science science, and they apply to anyone who wants to do science. The ID advocates are wrong, though, that the restriction has anything to do with naturalism. Intelligent design is not science because there is no objective evidence for it. It is that simple.

The ID advocates claim that they are the victims, that society is restricting their view that miracles must be accepted as an alternative to certain scientific findings. Really, though, they are the ones doing the restriction. Society, including science, already recognizes miracles as an alternative, just not as a scientific alternative. The ID advocates, in an attempt to look respectable and to gain a larger audience, want to break science so that their miracles will fit inside it. And they attack many people's religion as well. Their statements make it clear that their supernaturalism in science will not merely be an alternative; it will be mandatory (Forrest, 2002). And despite their populist claims, they want to include only the miracles they approve of. Beliefs such as theistic evolution are explicitly rejected. The "renewal of science and culture" that ID advocates call for will make science untrustworthy and force a sectarian view on a public with many diverse religious views. That is far too high a price for a change whose promised benefits are no more than what we have already.

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