今天你还在“波普”吗？

我在很多个场合都调侃过，“如果你还只知道Popper(波普)的科学哲学的话，你已经Out了！”不过，我通常并不展开。这几天翻一本旧书，找到了一个我觉得写得非常好的科普文章。这篇短文是Larry Laudan在the Arkansas creationism trial ( McLean v. Arkansas)写的。

该案的起因是这样的。1981年3月19日，阿肯色州州长签署法令（Act590），要求将“进化（演化）论”和“创世论（creationism）”平等对待，都要纳入公立学校的教纲当中，并且平等对待。之后，该州的一位牧师（！）Reverend William McLean发起对该项法令的申述。1982年1月5日，William Overton法官裁定，阿肯色州州长签署法令（Act590）违反了美国的宪法，因为美国宪法第一修正案规定，政府不能运用权力去支持任何宗教，而“创世论（creationism）”不是科学，而是(某一个)宗教（或者说是某个宗教的一个核心部分）。因此，阿肯色州“创世论（creationism）”需要被写入教纲的要求被驳回。

关于美国宪法第一修正案的背景：The First Amendment (Amendment I) to the United States Constitution prohibits the making of any law respecting an establishment of religion, impeding the free exercise of religion, abridging the freedom of speech, infringing on the freedom of the press, interfering with the right to peaceably assemble or prohibiting the petitioning for a governmental redress of grievances.

http://en.wikipedia.org/wiki/Establishment_Clause_of_the_First_Amendment。

http://en.wikipedia.org/wiki/First_Amendment_to_the_United_States_Constitution#Establishment_of_religion

案件背景：http://en.wikipedia.org/wiki/McLean_v._Arkansas#McLean_v._Arkansas_ruling

作为一个杰出的科学哲学家，Laudan当然欢迎审判的结果。但是，Laudan指出，如果“创世论（creationism）”懂一点科学哲学的话，他们可以将不利于他们的指控统统驳回。

这是因为，裁定该案件的William Overton法官拒绝接受教学“创世论（creationism）”的要求的理由（即，“创世论（creationism）”不是科学），如果按照法官自己列出的对“什么（才）是科学？”的标准，“创世论（creationism）”毫无问题地满足是“科学”的条件！而William Overton法官列出的对科学的标准的划定，几乎全部来自波普的对“什么才是科学？”的捍卫（著名的波普科学与非科学的“分界论”）。

因此，鼓励所有的青年学者和学生好好看看这个短文。否则，如果你遇到为有备而来的高手，你真有可能不得不承认，你从事的所谓的“科学”和“创世论（creationism）”并不差别！这将是多么的悲哀和无地自容呀！

Larry Laudan 是著名的科学哲学家之一，最重要的两部著作是Progress and Its Problems （1977）； Beyond Positivism and Relativism（1996）。

这篇短文是Larry Laudan, 1996, Beyond Positivism and Relativism其中的一个插叙。原文出版在Science, Technology, and Human Value ,7 (41): 16-10, 1982.

Science at the Bar--Causes for Concern

Larry Laudan （1982）

In the wake of the decision in the Arkansas creationism trial (McLean v. Arkansas), the friends of science have been relishing the outcome. The creationists quite clearly made a botch of their case and there can be little doubt that the Arkansas decision may, at least for a time, blunt legislative pressure to enact similar laws in other states. Once the dust has settled, however, the trial in general and Judge William R. Overton's ruling in particular may come back to haunt us; for, although the verdict itself is probably to be commended, it was reached for all the wrong reasons and by a chain of argument which is hopelessly suspect. Indeed, the ruling rests on a host of misrepresentations of what science is and how it works.

The heart of Judge Overton's opinion is a formulation of "the essential characteristics of science." These characteristics serve as touchstones for contrasting evolutionary theory with creationism; they lead Judge Overton ultimately to the claim, specious in its own right, that since creationism is not "science," it must be religion. The opinion offers five essential properties that demarcate scientific knowledge from other things: "(1) It is guided by natural law; (2) it has to be explanatory by reference to natural law; (3) it is testable against the empirical world; (4) its conclusions are tentative, i.e., are not necessarily the final word; and (5) it is falsifiable."

These fall naturally into two families: properties (1) and (2) have to do with lawlikeness and explanatory ability; the other three properties have to do with the fallibility and testability of scientific claims. I shall deal with the second set of issues first, because it is there that the most egregious errors of fact and judgment are to be found.

At various key points in the opinion, creationism is charged with being untestable, dogmatic (and thus nontentative), and unfalsifiable. All three charges are of dubious merit. For instance, to make the interlinked claims that creationism is neither falsifiable nor testable is to assert that creationism makes no empirical assertions whatever. That is surely false. Creationists make a wide range of testable assertions about empirical matters of fact. Thus, as Judge Overton himself grants (apparently without seeing its implications), the creationists say that the earth is of very recent origin (say 6,000 to 20,000 years old); they argue that most of the geological features of the earth's surface are diluvial in character (i.e., products of the postulated worldwide Noachian deluge); they are committed to a large number of factual historical claims with which the Old Testament is replete; they assert the limited variability of species. They are committed to the view that, since animals and man were created at the same time, the human fossil record must be paleontologically coextensive with the record of lower animals. It is fair to say that no one has shown how to reconcile such claims with the available evidence--evidence which speaks persuasively to a long earth history, among other things.

In brief, these claims are testable, they have been tested, and they have failed those tests. Unfortunately, the logic of the opinion's analysis precludes saying any of the above. By arguing that the tenets of creationism are neither testable nor falsifiable, Judge Overton (like those scientists who similarly charge creationism with being untestable) deprives science of its strongest argument against creationism. Indeed, if any doctrine in the history of science has ever been falsified, it is the set of claims associated with "creation science." Asserting that creationism makes no empirical claims plays directly, if inadvertently, into the hands of the creationists by immunizing their ideology from empirical confrontation. The correct way to combat creationism is to confute the empirical claims it does make, not to pretend that it makes no such claims at all.

It is true, of course, that some tenets of creationism are not testable in isolation (e.g., the claim that man emerged by a direct supernatural act of creation). But that scarcely makes creationism "unscientific." It is now widely acknowledged that many scientific claims are not testable in isolation, but only when embedded in a larger system of statements, some of whose consequences can be submitted to test.

Judge Overton's third worry about creationism centers on the issue of revisability. Over and over again, he finds creationism and its advocates "unscientific" because they have "refuse[d] to change it regardless of the evidence developed during the course of the [ir] investigation." In point of fact, the charge is mistaken. If the claims of modern-day creationists are compared with those of their nineteenth-century counterparts, significant shifts in orientation and assertion are evident. One of the most visible opponents of creationism, Stephen Gould, concedes that creationists have modified their views about the amount of variability allowed at the level of species change. Creationists do, in short, change their minds from time to time. Doubtless they would credit these shifts to their efforts to adjust their views to newly emerging evidence, in what they imagine to be a scientifically respectable way.

Perhaps what Judge Overton had in mind was the fact that some of creationism's core assumptions (e.g., that there was a Noachian flood, that man did not evolve from lower animals, or that God created the world) seem closed off from any serious modification. But historical and sociological researches on science strongly suggest that the scientists of any epoch likewise regard some of their beliefs as so fundamental as not to be open to repudiation or negotiation. Would Newton, for instance, have been tentative about the claim that there were forces in the world? Are quantum mechanicians willing to contemplate giving up the uncertainty relation? Are physicists willing to specify circumstances under which they would give up energy conservation?Numerous historians and philosophers of science (e.g., Kuhn, Mitroff, Feyerabend, Lakatos) have documented the existence of a certain degree of dogmatism about core commitments in scientific research and have argued that such dogmatism plays a constructive role in promoting the aims of science. I am not denying that there may be subtle but important differences between the dogmatism of scientists and that exhibited by many creationists; but one does not even begin to get at those differences by pretending that science is characterized by an uncompromising open-mindedness.

Even worse, the ad hominem charge of dogmatism against creationism egregiously confuses doctrines with the proponents of those doctrines. Since no law mandates that creationists should be invited into the classroom, it is quite irrelevant whether they themselves are close-minded. The Arkansas statute proposed that creationism be taught, not that creationists should teach it. What counts is the epistemic status of creationism, not the cognitive idiosyncrasies of the creationists. Because many of the theses of creationism are testable, the mind set of creationists has no bearing in law or in the fact on the merits of creationism.

What about the other pair of essential characteristics which the McLean opinion cites, namely, that science is a matter of natural law and explainable by natural law? I find the formulation in the opinion to be rather fuzzy; but the general idea appears to be that it is inappropriate and unscientific to postulate the existence of any process or fact which cannot be explained in terms of some known scientific laws--for instance, the creationists' assertion that there are outer limits to the change of species "cannot be explained by natural law." Earlier in the opinion, Judge Overton also writes "there is no scientific explanation for these limits which is guided by natural law," and thus concludes that such limits are unscientific. Still later, remarking on the hypothesis of the Noachian flood, he says, "A worldwide flood as an explanation of the world's geology is not the product of natural law, nor can its occurrence be explained by natural law." Quite how Judge Overton knows that a worldwide flood "cannot" be explained by the laws of science is left opaque; and even if we did not know how to reduce a universal flood to the familiar laws of physics, this requirement is an altogether inappropriate standard for ascertaining whether a claim is scientific. For centuries scientists have recognized a difference between establishing the existence of a phenomenon and explaining that phenomenon in a lawlike way. Our ultimate goal, no doubt, is to do both. But to suggest, as the McLean opinion does repeatedly, that an existence claim (e.g., there was a worldwide flood) is unscientific until we have found the laws on which the alleged phenomenon depends is simply outrageous. Galileo and Newton took themselves to have established the existence of gravitational phenomena long before anyone was able to give a causal or explanatory account of gravitation. Darwin took himself to have established the existence of natural selection almost a half-century before geneticists were able to lay out the laws of heredity on which natural selection depended. If we took the McLean opinion criterion seriously, we should have to say that Newton and Darwin were unscientific; and, to take an example from our own time, it would follow that plate tectonics is unscientific because we have not yet identified the laws of physics and chemistry which account for the dynamics of crustal motion.

The real objection to such creationist claims as that of the (relative) invariability of species is not that such invariability has not been explained by scientific laws, but rather that the evidence for invariability is less robust than the evidence for its contrary, variability. But to say as much requires renunciation of the opinion's order charge--to wit, that creationism is not testable.

I could continue with this tale of woeful fallacies in the Arkansas ruling, but that is hardly necessary. What is worrisome is that the opinion's line of reasoning--which neatly coincides with the predominant tactic among scientists who have entered the public fray on this issue--leaves many loopholes for the creationists to exploit. As numerous authors have shown, the requirements of testability, revisability, and falsifiability are exceedingly weak requirements. Leaving aside the fact that (as I pointed out above) it can be argued that creationism already satisfies these requirements, it would be easy for a creationist to say the following: "I will abandon my views if we find a living specimen of a species intermediate between man and apes." It is, of course, extremely unlikely that such an individual will be discovered. But, in that statement the creationist would satisfy, in one fell swoop, all the formal requirements of testability, falsifiability, and revisability. If we set very weak standards for scientific status--and, let there be no mistake, I believe that all of the opinion's last three criteria fall in this category-then it will be quite simple for creationism to qualify as "scientific."

Rather than taking on the creationists obliquely and in wholesome fashion by suggesting that what they are doing is "unscientific" tout court (which is doubly silly because few authors can even agree on what makes an activity scientific), we should confront their claims directly and in piecemeal fashion by asking what evidence and arguments can be marshaled for and against each of them. The core issue is not whether creationism satisfies some undemanding and highly controversial definitions of what is scientific; the real question is whether the existing evidence provides stronger arguments for evolutionary theory than for creationism. Once that question is settled, we will know what belongs in the classroom and what does not. Debating the scientific status of creationism (especially when "science" is construed in such an unfortunate manner) is a red herring that diverts attention away from the issues that should concern us.

Some defenders of the scientific orthodoxy will probably say that my reservations are just nit-picking ones, and that--at least to a first order of approximation—Judge Overton has correctly identified what is fishy about creationism. The apologists for science, such as the editor of The Skeptical Inquirer, have already objected to those who criticize this whitewash of science "on arcane, semantic grounds . . . [drawn] from the most remote reaches of the academic philosophy of science." But let us be clear about what is at stake. In setting out in theMcLean opinion to characterize the "essential" nature of science, Judge Overton was explicitly venturing into philosophical terrain. His obiter dicta are about as remote from well-founded opinion in the philosophy of science as creationism is from respectable geology. It simply will not do for the defenders of science to invoke philosophy of science when it suits them (e.g., their much-loved principle of falsifiability comes directly from the philosopher Karl Popper) and to dismiss it as "arcane" and "remote" when it does not. However noble the motivation, bad philosophy makes for bad law.

The victory in the Arkansas case was hollow, for it was achieved only at the expense of perpetuating and canonizing a false stereotype of what science is and how it works. If it goes unchallenged by the scientific community, it will raise grave doubts about that community's intellectual integrity. No one familiar with the issues can really believe that anything important was settled through anachronistic efforts to revive a variety of discredited criteria for distinguishing between the scientific and the nonscientific. Fifty years ago, Clarence Darrow asked, apropos the Scopes trial, "Isn't it difficult to realize that a trial of this kind is possible in the twentieth century in the United States of America?" We can raise that question anew, with the added irony that, this time, the pro-science forces are defending a philosophy of science which is, in its way, every bit as outmoded as the "science" of the creationists.