Can science justify universal human rights? - a reply to Sam Harris's Moral Landscape Challenge.
Is scientific inquiry restricted to nature? - at NPR's 13.7 Cosmos and Culture, co-authored with Ursula Goodenough, and relatedly:
Reality and Its rivals: putting epistemology first - Being epistemically responsible pushes us toward science and increases the plausibility of naturalism.
Can science test supernatural worldviews? - an excellent paper by Yonatan Fishman, Dept. of Neurology, Albert Einstein College of Medicine, answering in the affirmative.
Some criteria for good scientific explanations - not definitive of course, but a first cut at the basics, showing that scientific practice doesn't presume the natural/supernatural distinction.
Mike Beyer's essentials of scientific explanation - a boiled-down list of criteria for good explanations and why they matter.
It's wrong to say science excludes God, experts say - but nevertheless, god is excluded from scientific explanations; by Sharon Begley, science reporter for the Wall Street Journal.
On the integrity of science - If Kansas insists on introducing supernaturalism into science, then science equally insists on showing supernaturalism the door.
2 critiques of new age pseudo-science (on the New Age page) Those of the New Age persuasion often suppose that reductionist science threatens what makes us most human, the immaterial soul or spirit, and what makes life most meaningful, the existence of a transcendent non-physical realm. To escape the perils of materialism and mechanism, they take refuge in the pseudo-science of paranormal and occult phenomena. But we needn't resort to pseudo-science or deny our physical nature to defend humanity or find meaning in life.
Science and freedom - Mainstream science supports a physicalist
understanding of human beings and their behavior which challenges traditional
notions of self and free will. But a fully naturalistic, science-based
view of ourselves nevertheless provides a robust basis for morality, while
pointing the way toward humane revisions in our responsibility practices.
Dembski, naturalist? - Intelligent design advocate William Dembski argues correctly that science shouldn't presume naturalism. But he also argues, correctly, that if science confirms the existence of an intelligent designer, such an entity becomes part of the natural world. Is this really what proponents of intelligent design want?
- An open letter to proponents of intelligent design -
Using science to prove the existence of God is like trying to draw a round square. The aims and methods of science strive to unify our understanding of the world, and such an understanding inevitably tends to undermine the dualistic claim that a categorically different supernatural realm exists.
Dear Msrs. Johnson, Behe, Dembski, Calvert, et al.:
As leaders of the movement to bring intelligent design into science education, you believe that science, properly construed, can get us to God. You claim that science as it’s usually presented presumes naturalism as a philosophical starting point, and so rules out intelligent design (ID) on grounds that ID is supernatural. If only science and scientists would rid themselves of this naturalistic bias, then the design hypothesis could compete with Darwinian accounts on an equal footing, thus lending scientific support for the existence of divine intervention in human affairs. You say that as long as science persists in this discriminatory philosophical assumption, it violates the constitutional prohibition on government establishing or favoring a particular religious or philosophical viewpoint. Therefore, in order to restore philosophical balance into science, states should challenge its presumption of naturalism by requiring that science teachers present ID as a viable scientific hypothesis. 1
But, does science as it’s currently practiced really presume naturalism? Does science invoke a metaphysical assumption about causes being strictly natural in order to conduct it’s inquiry? Do scientists start out by declaring their allegiance to naturalism and their rejection of the supernatural? It would seem not. The vast majority of scientific texts, papers, experiments, hypotheses, conjectures, and napkin scribblings make no mention of the natural/supernatural distinction. Scientists rarely, if ever, pronounce up front an allegiance to naturalism as a guiding philosophy when laying out their methodological presuppositions (if indeed that is their guiding philosophy, since many scientists are religious). Science operates without any a priori ontological commitment as to what sorts of entities exist. It need not make such claims in advance, and indeed to make them might very well bias inquiry. Science is, and should be, open to the existence of any entity which gains sufficient empirical, theoretical support in the course of scientific investigation and explanation.
But although science does not presume naturalism, scientific inquiry tends by its very nature to unify our understanding of the world, and such unity is indeed the heart of naturalism. The basic characteristics of scientific explanation 2 are such that phenomena are connected within theories across vastly different levels (from molecules to galaxies) and types (from neurons to consciousness to culture). The success of science lies exactly in demonstrating that empirically grounded fundamental laws, constants, and particles (whether conceived as matter or energy) are the universal building blocks from which all other phenomena in its purview are constructed. The world described by science is of a piece, and necessarily so, since scientific explanations are just those which show how phenomenon X arises as a function of phenomena Y and Z. Whatever becomes the object of scientific investigation will, if the investigation is successful, be incorporated within the single, unified understanding that is the goal of science. Although scientific theories have and will continue to change in response to new objects of inquiry, the goal of science does not.
Monistic naturalism is, therefore, simply the result of sticking with science as one’s preferred route to knowledge about the ultimate constituents of the world. God, traditionally conceived of as a non-physical, spiritual being set apart or above nature in some respect, 3 is logically barred from being incorporated into a scientific understanding of the world. Science as it’s practiced can’t get us to God, since God is exactly that which escapes being pinned down as one of many facts or entities within a unified understanding of existence. Put another way, if science as its currently practiced were successful in proving the existence of God, that god could no longer have the supernatural characteristics traditionally attributed to it. 4 In its pursuit of comprehensive explanations, science tends toward ontological unification, not dualism.
Perhaps, you might say, scientific methods of explanation, although they don’t explicitly presume naturalism or make mention of the natural/supernatural distinction, are nevertheless biased by virtue of this unifying tendency, a tendency which rules out categorically supernatural entities from being included in science. Why should science be monistic and not dualistic in its aims and methods? Doesn’t this constitute a motivational and methodological prejudice that infects the heart of empirical inquiry?
The answer is that scientific inquiry is driven by the urge for explanatory unification, so that in questioning that urge, you question science itself. Scientific empiricism is a human, motivated enterprise that speaks to a defining human characteristic: the desire to understand, predict, and control. From a wider standpoint (which I strongly encourage everyone to adopt), such a desire is just one among many human motives, and so science isn’t the only game in town, by any stretch. But, you can’t fault science for its drive for unity, since that’s just an expression of a widely shared human motive, a motive as valid as the desire for food, companionship, and discovering meaning in life. 5
of us that stick with science in deciding knowledge claims about what
fundamentally exists aren’t compelling anyone else to do so. You are free
to justify what you believe is true by any and all means that suit you, e.g.,
appeals to faith, tradition, commonsense, intuition, revelation – whatever it
may be. But equally, you can’t compel science to lead where, by it’s very
nature, it cannot. Such an effort can only end in the manifest contradiction
of using methods which generate ontological unity while trying to safeguard the
categorically different nature of a deity, designer, or supreme intelligence.
It can’t be done anymore than you can draw a round square.
Tom Clark, www.naturalism.org
1. See, for instance, Phillip Johnson’s work, at http://www.arn.org/johnson/johome.htm, or the letter by John Calvert mailed to Kansas school board members, at http://www.intelligentdesignnetwork.org/June%208%20letter%20to%20Boards.htm. For the impact of this line of thought on proposed legislation, see Ohio bill HB 481, which ostensibly "seeks to promote effective science education." In its statement of intent, this bill says: "Presently national science organizations and others use an irrebuttable assumption that phenomena in nature result only from a combination of chance and natural law - the laws of chemistry and physics - and that design conceptions of nature are invalid in scientific inquiry. This is essentially a philosophical assumption and not a scientific conclusion based on a scientific investigation and analysis per the scientific method. The assumption is technically called methodological naturalism. It is also known as "scientific materialism."....Good science and effective science education requires that origins science be conducted objectively and without an irrebuttable naturalistic assumption, or, for that matter, any other religious or philosophic assumption." My claim here is that this statement badly misdiscribes science as it's practiced, in that it makes no irrebuttable or philosophical assumption about naturalism.
2. For some examples of such characteristics, and why the intelligent design hypothesis doesn’t exemplify them, see "Why Intelligent Design Isn’t Science" at http://www.naturalism.org/science.htm.
3. For a discussion of the supernatural/natural distinction, see "Spirituality Without Faith," the section on naturalism. http://www.naturalism.org/spiritua1.htm
4. For an excellent discussion of the antipathy between science and dualism in the context of consciousness studies, see Maurice K.D. Schouten, "Theism, Dualism, and the Scientific Image of Humanity," Zygon, V36 #4, December 2001, pp. 679-708. See also Dembski, naturalist? about the naturalization of God that would likely ensue were he scientifically demonstrated to exist.
5. Meaning in life is quite discoverable within a naturalistic view of the world, see the spirituality page at http://www.naturalism.org/spiritua.htm.
Contrary to the claims of some proponents of intelligent design (ID), science does not presume naturalism. So science doesn't reject ID because ID is supernatural. Nevertheless, science does reject ID because the ID hypothesis is unsupported by evidence and exemplifies none of the characteristics of good scientific explanations. For some basic characteristics of scientific explanations, see here.
Some of those sympathetic to intelligent design (ID) argue that science as it’s currently taught assumes naturalism, and further that science tries to rule out ID as unscientific on the grounds that ID invokes the supernatural. 1 But science makes no claims about naturalism. Scientists simply propose explanations which are accepted or rejected on the basis of their scientific merit.
Intelligent design fails as science not because science a priori rules out the supernatural (methodologically it doesn’t need to do this, and in fact wastes no time on the matter), but because the intelligent design hypothesis has no merit as a scientific explanation.
Because science doesn’t presume naturalism, there’s no basis for supposing it violates any U.S. constitutional prohibition on states favoring or establishing a particular religious or philosophical view. So ID need not be imported into the science curriculum to provide "balance" or give non-naturalistic views "equal time." Because ID conclusively fails as good science, it should not be presented or taught as a viable scientific alternative to Darwinian accounts of evolution. But ID could usefully be discussed as good example of a failed scientific hypothesis, helping to clarify what science actually is, and does.
Below, I’ve set out what I take to be some fairly uncontroversial, central characteristics of legitimate scientific explanation, and then list reasons why ID doesn’t embody or exemplify these characteristics. I don’t pretend that these are exhaustive, that they aren’t redundant to some extent, or couldn’t be improved upon in many respects, so I invite interested parties to improve upon them (e.g., see here for Mike Beyer's nice synthesis of the 10 characteristics listed below). But it’s crucial to note that in characterizing science, none of the points below invoke the natural/supernatural distinction. By virtue of its aims and methods, science ends up producing a unified view of the world, what we call nature, but it doesn’t start out with ontological assumptions that make it partisan to naturalism.
A first cut at some basic characteristics of scientific explanation:
Note: see Mike Beyer's synthesis of these 10 points into 4 essentials of scientific explanation: coherence, verifiability, transparency, and simplicity.
Why intelligent design (ID) isn’t good science (the corresponding points above are in parentheses):
On proving a negative: In general, ID is a negative thesis - that standard evolutionary explanations cannot, however well elaborated, account for some particular phenomena, e.g., "irreducible complexity." The plausibility of the design hypothesis is thus only a function of the purported failure of selectionist explanations. But there is no argument to support the idea that selectionist explanations will not or cannot be completed, especially as biological mechanisms become better understood, and indeed many selectionist explanations are complete to the satisfaction of many scientists. This means, if selectionist explanations are completed and filled out to a reasonable degree (what’s reasonable is of course a bone of contention), then the intelligent design hypothesis loses this sort of support. The same goes for the origins of life: once a plausible mechanism is established, then ID becomes otiose.
On falsifiability: It is often supposed, although not universally agreed, that scientific hypotheses and conjectures are at least in principle falsifiable, if not directly testable. In contrast, ID is unfalsifiable: no experiment could prove or disprove it. ID simply says that what selectionism or other science can’t explain is explicable by appeal to design, so ID can always fill the gaps left by science: thus there’s no way to prove it wrong. (This point is taken from Larry Arnhart’s piece" Evolution and the New Creationism: A Proposal for Compromise," Skeptic V8#4, 2001, p. 48.)
On low probability events: Science accepts the possibility that certain events and conditions may have been extremely low probability occurrences, but doesn’t draw any ontologically inflationary conclusions from this. In contrast, ID draws the inference that since (let us concede for the sake of argument) it’s highly improbable that the universe has constants which are favorable to life, or that life arose at all, there must have been an intelligent agent that chose the constants and/or created life. But this inference simply begs the question of the prior probability of the existence of the designer.
1. See, for instance, Phillip Johnson’s work, at http://www.arn.org/johnson/johome.htm, or the letter by John Calvert mailed to Kansas school board members, at http://www.intelligentdesignnetwork.org/June%208%20letter%20to%20Boards.htm.
2. "Enthusiasts for ID ignore the growing laboratory evidence for the selection of biological function from random collections of proteins and nucleic acids. Molecular biologists and biotechnologists have shown that selection acting on randomly generated libraries of billions or trillions of biological polymers, such as peptides or RNA molecules, can produce molecules with useful biological functions, such as specificities for small ligands or catalytic activities. Computer scientists, complexity theorists, and even physical chemists have also documented striking examples of order that develops spontaneously. It is simply no longer tenable to equate order, complex structure, or sophisticated function uniquely with conscious design." From Greenspan, N. S., "Not-So-Intelligent Design," The Scientist 16 :12, March 4, 2002, at http://www.the-scientist.com/yr2002/mar/opin_020304.html.
3. "A truly fundamental problem with the notion of ID, as a scientific idea, is that, ultimately, it has effectively no explanatory or predictive power. Suggesting that an unknown Intelligent Designer of unspecified attributes designed the eye, the clotting cascade, or the immune system offers no scientific insights into these biologic marvels and suggests no incisive experiments." Ibid.
4. In response to this objection, Michael Behe has posited an aesthetic motive which prompts the designer to put "flaws" in his creations, but this assumes just those characteristics of a designer needed to explain design, so is ad-hoc (2). This point is taken from Larry Arnhart’s piece "Evolution and the New Creationism: A Proposal for Compromise," Skeptic V8#4, 2001, p. 49.
TWC 3/02, revised 7/09
Mike Beyer's essentials of scientific explanation
Having surveyed the proposed criteria of explanatory adequacy above, Mike Beyer suggested that they could be synthesized into four essential principles. He wrote:
...I began to wonder if there were some way to boil
down the essentials of scientific explanation into a few words or mnemonics. As
a first cut, I'd thought of the following list of features and why they
matter might help us naturalists keep our core principles "in our back
pocket" so to say:
This replies to the claim by John Calvert of the Intelligent Design Network that science as it's currently taught in public school isn't true, objective science because it rules out intelligent design (ID) as a viable hypothesis. True science, driven by the human desire to know, predict and control, must rule out ID, since ID lacks empirical support and fails as a productive scientific hypothesis.
True science, we might all agree, has as its goal objectivity, not bias. So Calvert, in claiming objectivity for the sort of science that countenances intelligent design, claims the mantle of the true scientist. On the other hand, he says mainstream scientists who find intelligent design to be non-science aren’t really doing science. Instead, they’re doing scientific materialism or methodological naturalism, illicitly restricting the scope of scientific explanation to rule out the idea that life could be caused by a purposive intelligence.
Note that this is an empirical claim that Calvert makes. Do mainstream scientists have as their goal “to infer only natural and material causes… for all natural events and phenomena”? No, what scientists actually do is seek the best explanation for phenomena according to widely accepted explanatory criteria, none of which invoke the natural/supernatural distinction. These criteria, among which are ontological conservatism, mechanistic transparency, observational support, experimental replicability, predictive success, connection between classes of phenomena, and theoretical productivity, have yielded the most reliable and unifying sorts of knowledge we possess. Science as a method has itself evolved under the selective pressure of the demand for dependable and comprehensive understanding, and these criteria are the winnowed out result. But it does not, and never has, specified in advance of its explanations what’s natural and what’s supernatural.1
Instead, what’s happened is that scientific explanations and theories, using ontologically and philosophically neutral methods, have gradually defined what’s natural, as opposed to what’s supernatural. Those entities and regularities that secure a place in scientific descriptions of the world (e.g., molecules, neurons, species, the law of gravity) are part of what we call nature, and those that haven’t yet (e.g., unicorns, clairvoyance, morphogenetic fields, astral bodies) are perforce excluded. So it’s not that science prejudges what’s natural as it proceeds, although in building upon existing scientific knowledge it necessarily invokes natural phenomena. Rather, it constructs our conception of nature by virtue of its explanatory success, expanding the domain of our reliable understanding of the world. And science can consider any candidate hypothesis tendered for evaluation, natural or supernatural, as long as it has at least some content amenable to potential observation or experiment (if it doesn’t, then it can’t be evaluated). As skeptic Michael Shermer put it on a PBS TV special on The Question of God, “the existence of god is an empirical question.” If you can sufficiently specify your god, we can scientifically test for it. If you can’t, then do you really know what you believe in?
Now, Calvert might take issue with this empirical claim about what science is and what scientists do, and point to various declarations by scientists that they are indeed materialists or “methodological naturalists.”2 But if they are such, it’s only in the benign sense mentioned above, that scientists will first look for explanatory resources within existing science, which is perforce about nature as we currently understand it. This, to repeat, is not to decide in advance what counts as natural according to some philosophical or ideological criterion, but to proceed on the basis of the relatively secure knowledge already in hand about what we call the natural world.
So, if this account of science is true, Calvert et al. can no longer claim that science is biased toward naturalism in the way they suggest, and their case collapses for an “objective” science that would entertain hypotheses empty of testable or observable content. Given that the canon of scientific explanation is philosophically neutral, and that the intelligent design conjecture is indeed empty, ID could only be taught as an object lesson in bad science, as a failed hypothesis.
The last tactic available to those wanting ID to count as viable science is to amend the explanatory criteria that our desire for reliable, unifying knowledge has produced. Imagine that they manage to require, by voter initiative, court decision, or legislation, that science taught in public schools must include among its accepted, viable explanations that phenomena are produced by unspecified agents or intelligences. [note: this happened in Kansas as of December, 2005] Instead of having to understand and apply the theory of natural selection in explaining the body plans of organisms, students could simply cite a designing intelligence about which nothing is known.
As soon as this possibility is broached, its failure as scientific explanation is apparent. The design hypothesis tells us precisely nothing about the processes or mechanisms of creation, and only these can actually explain how the phenomenon in question came to be as it is. Explanations that appeal to unknown, unspecified agencies play no role in science since they produce no reliable knowledge, in fact no knowledge whatsoever. So the mandate that such explanations be part of science would be futile; it would simply be ignored by practicing scientists in favor of explanations involving specifiable processes and mechanisms. And learning it as an explanatory maxim would put students at serious disadvantage in competition for science jobs, and jeopardize their understanding of how the world works. So revising the explanatory requirements of science by fiat must inevitably fail.
There is, finally, no principled reason or practical basis upon which intelligent design could be introduced into the public school science curriculum except as an example of failed science. True, effective science, driven by the human desire to know, predict and control, won’t countenance any elision in our understanding. Science isn’t philosophically biased, nor can intelligent design count as good science. Until independent evidence accrues that establishes the nature and existence of the designer, there's no reason to suppose he exists.
TWC, 3/05, revised 7/09
1. See http://www.naturalism.org/science.htm for more on this.
2. For instance, here’s an excerpt from an interview with Barbara Forrest, co- author with Paul Gross of Creationism’s Trojan Horse: The Wedge of Intelligent Design: “Science, however, is a naturalistic enterprise. Scientists cannot appeal to supernatural explanations because there is neither a methodology for testing them nor an epistemology for knowing the supernatural. Science has a naturalistic methodology, known less controversially as ‘scientific method.’ That simply means that scientists seek natural explanations for natural phenomena. Science also has an epistemology, namely, the use of human sensory faculties to collect empirical data about the world and the use of our rational faculties to draw conclusions and construct explanations of this data. This is the only successful way to do science, and the pragmatic success of this naturalistic methodology is the only reason scientists use it. There is neither a conspiracy by scientists to prohibit “alternative explanations” nor an arbitrary commitment to naturalism, as ID proponents charge. Scientists use this naturalistic methodology because it works. Period.”
Intelligent design advocate William Dembski argues correctly that science shouldn't presume naturalism. But he also argues, correctly, that if science confirms the existence of an intelligent designer, such an entity becomes part of the natural world. Is this really what proponents of intelligent design want?
In his article “In Defense of Intelligent Design”, William Dembski takes Barbara Forrest, Eugenie Scott and others to task for supposing that science is governed by “methodological naturalism” or “methodological materialism.” This is to suppose that in investigating the world, science should consider only natural or material explanations and causes (see the section on “Methodological materialism,” pp. 8-12). Dembski objects that methodological naturalism/materialism pre-judges the question of whether nature might contain not just material causes, but “intelligent causes” as well, what he calls “mind” and “designing intelligence.” Science should be free to investigate these other sorts of causes, which, if confirmed, would not be supernatural or magical (the stuff of miracles), but natural, insists Dembski. Remarkably enough, in making these claims Dembski comes across as a naturalist: his preferred way of knowing about phenomena – science – generates a single natural world which would include even a designing intelligence, were it discovered.
Dembski has a plausible point about methodological naturalism, also made here. Science needn’t define itself as the search for “natural” or material causes for phenomena. In actual empirical fact, in building explanations and theories, science proceeds quite nicely without any reference to the natural/supernatural distinction. Science is defined not by an antecedent commitment to naturalism (whether methodological or ontological), but by criteria of explanatory adequacy which underpin a roughly defined, revisable, but extremely powerful method for generating reliable knowledge. These criteria can themselves be understood as having being selected for (during the more or less spontaneous development of science) by virtue of giving us the capacity to predict and control our circumstances, and by giving us a unified picture of the diversity of phenomena that, as cognitive creatures, we find deeply satisfying. The world that science gives us is what we call nature.
Taking up Dembski’s suggestion, what would happen if science were to admit the possibility of intelligent causes? Well, we know what would happen. Scientists would take the proposed explanatory hypothesis involving mind or designing intelligence and test it against accepted criteria of explanatory adequacy. For instance: Does the hypothesis say anything about the designing intelligence? Does it specify the relations of the hypothesized mind to material phenomena already established by science? Does it proffer any mechanisms of action, that is, does is describe how the proposed intelligent cause (as opposed to material cause) might make things happen? Are there any testable consequences of the hypothesis? Is there independent evidence of the cause apart from its hypothesized role in design? These are the tough, routine questions science asks, and there’s nothing in them that presupposes naturalism.
In point of fact, science has already interrogated intelligent design, and ID has nothing to say. It’s taken a good hard look at the explanatory resources of ID, and found them to be critically wanting, indeed completely vacuous. Although Dembski is right that science shouldn’t define itself by reference to naturalism (and in actual practice it doesn’t), his call for open-mindedness and philosophical neutrality on the part of scientists doesn’t help his cause. ID fails not because mainstream scientists pronounce the hypothesis that there are intelligent causes “supernatural” and thus off-limits to investigation, but because the hypothesis simply has nothing going for it empirically.
As noted above, Dembski states correctly that if science were to confirm the existence of an intelligent designer, then it would be naturalized – it would be part of an expanded natural world, not resident in a categorically distinct supernatural realm. Would proponents of ID really welcome such a development? After all, the functions of god – to create the universe, and to provide extra-natural foundations for meaning and morality – could hardly be fulfilled by something resident within nature. Dembski et al should be careful what they wish for, for if science gets us to god, it may not be quite what they hoped.
 This is Dembski’s contribution to the forthcoming Oxford Handbook of Religion and Science, edited by Philip Clayton; see http://www.designinference.com/documents/2005.06.Defense_of_ID.pdf
 In a way, the injunction of methodological naturalism to search for natural causes simply states a plausible scientific conservatism: before concocting wild and crazy hypotheses, first look within scientifically-certified nature when devising explanations. This is fair enough, but regrettably, some on both sides of the ID debate (including Dembski) misconstrue this injunction as saying that science has a commitment to metaphysical or ontological naturalism. Dembski is wrong to suppose that Forrest and Scott make this mistake, since they both disavow ontological naturalism as essential to the conduct of science. But there’s little question that the phrase “methodological naturalism” has sown considerable confusion about the philosophical commitments of science. Let’s just call what science does “science.”
One cut at these criteria is
Proposed changes, e.g., to drop #7 (“an explanation can’t simply be
posited to match the target phenomenon in order to fill an explanatory
gap - there has to be independent evidence of the features of the
explanation”), will only be accepted if in fact they
get us more reliable knowledge. Regarding the nature of
scientific explanations, the final court of appeal is always real-world
results; about which see the conclusion of “True science: does it
presume naturalism?” at
If Kansas insists on introducing supernaturalism into science, then science equally insists on showing supernaturalism the door.
Such questions are very much on the front burner thanks to recent (2005) revisions to science standards adopted by the Kansas Board of Education, including the redefinition of science itself to permit consideration of supernatural causes. Is it even logically possible for science to traffic in the supernatural? It seems obvious that science is restricted to natural phenomena, both in its purview and in its explanations.
There are of course esteemed governing bodies such as the National Academy of Sciences, the American Association for the Advancement of Science and the National Science Teachers Association, that explicitly define science and good scientific practice. There’s also the National Center for Science Education led by the intrepid Eugenie Scott, who makes the rounds defending science against ID, most recently and successfully in the Kitzmiller trial.
These groups indeed promulgate a definition of science that bars consideration of the supernatural, and have taken Kansas to task for crossing that line. For instance, the National Academy of Science says in Teaching About Evolution and the Nature of Science, p. 58:
And the National Science Teachers Association says (also in Teaching About Evolution..., p. 124):
But these definitions raise a further question: from whence comes our conception of the natural? What I’d suggest is that the very idea of the natural has been generated by science itself. The importance of this point for the science-religion debate is that science does not, as proponents of ID and religion often argue, make any apriori metaphysical or ontological claims about the world. In particular, it doesn’t assume a pre-existing natural world separate from the supernatural that gets identified on extra-scientific or philosophical grounds. Rather, science is in the business of providing transparent, unified, evidence-based and intersubjectively testable explanations of phenomena. In so doing, science identifies phenomena that end up playing well-confirmed roles in such explanations, and these end up constituting what we call nature. So science doesn’t presume naturalism; it isn’t, as the Kansas Board of Education says in its revisions, “driven by a naturalistic preconception.” Since science is metaphysically neutral it doesn’t need to be “balanced” by requiring the consideration of supernatural causes.
Importantly, explanations involving intentional, purposeful agents whose properties and characteristics cannot be specified are disallowed in science, but not because such agents are apriori supernatural. Rather, it’s simply that invoking an unspecified agent is an explanatory dodge, since particular intentions and actions can simply be posited to close a purported explanatory gap (e.g., to create the bacterial flagellum or human eye in one fell swoop). This is why when ID proponents claim that they aren’t necessarily invoking god, but perhaps a “natural” designer of some sort, they still aren’t doing science. There’s nothing wrong with invoking intelligent, intentional agents in explanations; after all, as such agents ourselves, we obviously play a huge role in explanations of culture and technology. But like everything else in an acceptable scientific theory, agents have to be sufficiently specified and thus at least potential candidates for empirical verification and explanation themselves. We human beings are pretty well specified by mainstream science, but ID notably fails to describe the designer.
Returning to the natural/supernatural distinction, we could ask: at what point were lightning bolts definitively shown to be natural phenomena, as opposed to the production of an angry god (Zeus, Jove, Jehovah, Yaweh)? Roughly, when science explained the various aspects of lightning (light, heat, duration, spatial distribution) in terms of other empirically verified, and thus natural, phenomena, none of which were agents. This rendered the agent hypothesis unnecessary since the explanatory gap had been closed. No longer was any intention needed to explain lightning bolts. This didn’t categorically disprove the existence of god, of course, but it helped define him as supernatural to the extent that in this domain, at any rate, he became explanatorily superfluous. The same goes for evolution: no agency need be posited, or if it is, it must be well-specified on pain of explanatory inadequacy.
The upshot is that Kansas, although politically free (fortunately) to define science any way it likes, is powerless to change scientific practice to suit what might be a majority of citizens in favor of considering supernatural causation. Supernatural causation is ruled out in science because the supernatural is just that which can’t play a role in transparently explaining the world to ourselves, which is what science does. This is a function of scientific practice, not an apriori rejection of the agent hypothesis. Specify the agent (e.g., god), test it against the evidence, and if it turns out to play a well-qualified role in our best theories, then the agent hypothesis will be accepted by science. But of course at that point the agent will be included in the natural world – it will have been naturalized – not exactly what Kansas has in mind for god.
As is commonly noted, the nature of science isn’t decided by vote or fiat. It’s rather the historically refined practice of winnowing out the best – the most economical, predictive, unifying and (perhaps) aesthetically pleasing – explanations of the world. This practice doesn’t assume naturalism or any other contestable worldview. However, it rules out the consideration (at least beyond the first-pass consideration necessary to disqualify them) of entities, causes and hypotheses that have no empirically specifiable content. Such entities, causes and hypotheses, should they involve intentional agency, just are the supernatural, since anything that is adequately specified and evidenced gets included in the natural world. If Kansas insists on bringing supernaturalism into science, then science equally insists, by virtue of its methods, not any tendentious ontological commitment, on showing supernaturalism the door.
concept of the supernatural is of course traditionally tied to the idea of
intentional agents (beings with purposes, intentions and plans), but the
idea of the supernatural as a categorically separate realm emerged in
parallel with the idea of physical nature as compositional and inanimate.
Before then, the spirit world and physical world were fully intertwined, not
distinct ontological categories. Minds and intentional agency, until
very recently, have been thought outside nature in some respect precisely
because they weren't susceptible to reductive explanation; they were (and
still are to a great extent) considered non-decomposable essences and
uncaused causers (see
Joshua Greene and Jonathan Cohen, p. 1782 on this). Of course
human agents are now virtually naturalized, but god resists naturalization
by virtue of being insufficiently specified by his adherents, or if
specified, empirically unevidenced.