by Lee McIntyre
What of Popper’s theory? Despite its virtues, it was severely criticized—by Kuhn and others—as offering too simple a picture of scientific theory change, especially given the fact that most science did not work precisely as the heroic example of Einstein’s prediction indicated. There are few such crucial tests, involving risky predictions and dramatic successes, in the history of science. Most of science actually grinds along fairly slowly, with tests on a much smaller scale and, tellingly, widespread reluctance to give up a workable hypothesis just because something has gone wrong.21 Yes, evidence counts, and one cannot simply ignore data and insulate a theory from refutation. Yet many philosophers, embracing the Duhem–Quine thesis (which says that it is always easier to sacrifice a smaller supporting hypothesis or make an ad hoc modification than to give up a theory), were skeptical that science worked as Popper said it did. Even though Popper maintained that his theory dealt only with the logical justification of science, many felt that there was a growing credibility gap between the way that scientists actually worked and the way that philosophers justified their work, given the sorts of social factors that Kuhn had identified. As Kuhn demonstrated, we are occasionally given to engage in a scientific revolution, but it does not happen nearly often enough for this to be accepted as the basis for demarcating between science and nonscience.
The upshot of all this is that by the 1970s, there was fairly wide agreement among most philosophers of science not only that the classic five-step scientific method was a myth, but also that there was no genuine methodological distinction between science and nonscience. This had great importance for the idea that science was special. Can one defend the idea that science is distinctive without also believing in scientific method or at least some other criterion of demarcation? Many said no.
Once Kuhn had opened the door to examining the workaday details of how scientists did their business—through “puzzle solving” and the search for accommodation to the dominant paradigm through “normal science”—the critics seemed unstoppable. To Kuhn’s horror (he did after all agree with Popper and other defenders of science that evidence counts and that the revolution from one scientific theory to another on the basis of this evidence is the hallmark of science), his work was often cited as support by those who no longer believed that science was special. Sociologists of science, relativists, postmodernists, social constructivists, and others took their turns attacking the idea that science was rational, that it had anything to do with the pursuit of truth, or indeed that scientific theories were anything more than a reflection of the political biases about race, class, and gender held by the scientists who produced them. To some, science became an ideology, and facts and evidence were no longer automatically accepted as providing credible grounds for theory choice even in the natural sciences.
Paul Feyerabend went so far as to claim that there was no method in science at all. This was a radical departure from merely giving up on the scientific method. Along for the ride went any claims about methodology (such as objectivity), a criterion of demarcation, and even the idea that scientific beliefs were privileged.22 Many wondered whether philosophy had now given up on science all together.
This is not to suggest that all philosophers of science felt this way. There were many who followed the ideas of Logical Empiricism (the successor to Logical Positivism), which held sway contemporaneously with Popper’s theory of falsification right through the Kuhnian revolution. Here the focus was on defending the special method of science—even picking up on the earlier positivist idea of a “unified science” whose method could be extended to the social sciences—not through falsifiability (or meaning), but through close examination of how one might build more credible and reliable theories even in the face of the problem of induction.23 Even here, though, it was necessary to modulate the full-throated defense of science, and certain concessions had to be made.24
By 1983, Larry Laudan, one of the most prominent philosophers of science, was ready to pull the plug on the idea that one could have a criterion of demarcation. Laudan’s work was not so radical as to suggest that science wasn’t important. He was one of the post-Kuhnians who looked for a way to uphold the idea that science could make “progress,” though certainly not toward “true” theories or in any way that suggested the hegemony of science over other ways of knowing. In his earlier-cited article “The Demise of the Demarcation Problem,” Laudan argued that there was no possible solution to the problem of demarcation, largely on the grounds that if it could be solved it would have been by now. By the time Laudan entered the picture, it goes without saying that there is no scientific method, but even the idea of finding another way of distinguishing between science and nonscience now seems dead.
Note that this does not necessarily mean that there is no difference between science and nonscience. One could even believe (as I think Laudan does) that science is uniquely explanatory. It’s just that we are not going to be able to find a workable device for demarcation. Even if we all agree in our bones what is science and what is not, we are not going to be able to create a hard and fast way to distinguish it. The technical reason for this, Laudan tells us, is that philosophers have not been able to come up with a set of necessary and sufficient conditions for science. And to him this seems to be an absolute requirement for fulfilling a criterion of demarcation.
What will the formal structure of a demarcation criterion have to look like if it is to accomplish the tasks for which it is designed? Ideally, it would specify a set of individually necessary and jointly sufficient conditions for deciding whether an activity or set of statements is scientific or unscientific. As is well known, it has not proved easy to produce a set of necessary and sufficient conditions for science. Would something less ambitious do the job? It seems unlikely. Suppose, for instance, that someone offers us a characterization which purports to be a necessary (but not sufficient) condition for scientific status. Such a condition, if acceptable, would allow us to identify certain activities as decidedly unscientific, but it would not help “fix our beliefs,” because it would not specify which systems actually were scientific. … For different reasons, merely sufficient conditions are equally inadequate. If we are told, “Satisfy these conditions and you will be scientific,” we are left with no machinery for determining that a certain activity or statement is nonscientific. … Without conditions which are both necessary and sufficient, we are never in a position to say ‘this is scientific: but that is nonscientific.25
What is the problem with giving only a necessary condition? It is too strict. By aiming to exclude all that is not science, we may also keep out some things that we would want to include. Suppose our necessary condition were that a science must be capable of performing controlled experiments. Doesn’t that rule out geology? Astronomy? All of the social sciences? Suppose, on the other hand, that we abandon this and instead aim at providing only a sufficient condition for scientific investigation: for instance, that it must be concerned with seeking truth based on empirical evidence. Here the concern is that we may have been too inclusive. Haven’t we now allowed as scientific the search for Bigfoot? By trying to include everything that is science, we may also let in those things that we would surely want to keep out.26 Thus, Laudan tells us, to have an adequate criterion of demarcation between science and nonscience, we need to specify a set of individually necessary and jointly sufficient conditions for science.27
There is perhaps no better illustration of the difficulties presented by adhering to such a lofty standard than Karl Popper’s own proposal of falsifiability. Is this intended to be a necessary standard for science, a sufficient one, or both? The search for an answer is maddening. In some places, Popper writes as if he intends his account to do any one of these. Consequently, his criterion has been criticized both for excluding legitimate science (such as evolutionary biology) and for allowing some of the pseudosciences (such as astrology) to seem scientific.28 Laudan in particular takes Popper to task for the latter, when he wr
ites that Popper’s criterion “has the untoward consequence of countenancing as ‘scientific’ every crank claim which makes ascertainably false assertions.”29
This last claim would surely enrage Popper (who designed his criterion specifically to keep things like astrology out of the scientific pantheon). So perhaps falsification should be interpreted as providing only a necessary condition?30 But, as we have seen, there is a weakness in this approach as well.31 So maybe it is best to accept the idea that Popper intended to meet the highest standard by providing an “individually necessary and jointly sufficient” set of criteria. Late in life, Popper did at one point say “a sentence (or a theory) is empirical-scientific if and only if it is falsifiable.”32 In philosophy of science, those are the magic words: “if and only if” commits him to providing both necessary and sufficient conditions. For the reasons already given, however, falsification alone will not do, yet one looks in vain in Popper’s writings for a definitive statement of what other conditions might apply. Frank Cioffi, in his important essay “Psychoanalysis, Pseudoscience, and Testability,” comes close, arguing that in addition to falsifiability, Popper had intended to include the requirements that “energetic attempts are made to put the theory to test” and that “negative outcomes of the tests are accepted.”33 But even here, one runs into the previously encountered problem, identified by Kuhn and others, that negative outcomes are not always accepted as overthrowing a theory.
If even Karl Popper gets caught up in the problem of providing the necessary and sufficient conditions that Laudan requires for offering a criterion of demarcation, some may wonder whether the rest of us should just give up. That is precisely what occurred for almost three decades after Laudan’s essay, when many were compelled by his reasoning to abandon the attempt to provide a criterion of demarcation between science and nonscience. This is not to say that they necessarily gave up on the idea that science was special. Remember that, like Laudan, one might believe that science could be defined by ostension. Surely many, like Laudan himself, were not ready to give up on the idea that science was worth defending, even if it could not be done through demarcation. With Laudan’s positive account that it was still possible for science to make “progress” along Kuhnian lines, many pulled back from some of Feyerabend’s and the social constructivists’ extreme assertions that science was just another way of knowing. The lament instead was that even if we know science (and pseudoscience) when we see them, we are prevented from having a good way to say what defines them. Even if many had given up on the problem of demarcation, they had not given up on science.
This strategy, however, had its costs. The low point was reached in 1982, when Act 590 was challenged on constitutional grounds in the case of McLean v. Arkansas. The prominent philosopher of science Michael Ruse was called to testify as an expert witness and, when backed into a corner about the definition of science, gave a version of Popper’s theory of falsifiability. This ended up convincing the judge, who quoted liberally from Ruse’s testimony in his opinion that creationism was not science, and therefore had no business in the science classroom. Although Ruse had done the best he could—and was in my view unfairly criticized for being bold enough to appear in court and prevent the travesty of seeing creationism accepted as legitimate scientific theory—the academics’ disapproval was swift and direct. Laudan, who surely agreed with Ruse that creationism was a farce, decried his use of Popper’s theory in the judge’s decision.
In the wake of the decision in the Arkansas Creationism trial. … the friends of science are apt to be relishing the outcome. … 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.34
Laudan’s worry can be summed up as follows:
Laudan replied that creationist doctrine itself is science by [Popper’s] criterion. It is obviously empirically testable since it has already been falsified. To be sure, its advocates have behaved in a nonscientific manner, but that is a different matter. The reason [creationism] should not be taught is simply that it is bad science.35
One imagines that if such scrupulously faithful adherence to the scholarship of the day had been allowed to hold sway in court the creationists would have been thrilled: yes, teach creationism as “bad” science, but teach it nonetheless.
Thus we see that failure to demarcate between science and nonscience can have real-world consequences outside philosophy. For one thing, the issue of teaching creationism in the public schools did not simply disappear in 1982, but instead has morphed and grown—partially as a result of philosophers’ inability to defend what is special about science—into the current claim that “intelligent design (ID)” (which I have elsewhere referred to as “creationism in a cheap tuxedo”) is now a full-fledged scientific theory that is ready for its debut in biology classrooms.36 This was again put to test at trial in 2005 in Kitzmiller v. Dover Area School District, where another judge—in a stinging rebuke that was reminiscent of the McLean decision—found that intelligent design is “not science” and ordered the defendants to pay $1 million to the plaintiffs. This may give pause to future ID theorists, but sadly this story is still not over, as current “academic freedom” bills are pending in the state legislatures of Colorado, Missouri, Montana, and Oklahoma, modeled on a successful 2012 Tennessee law that defends the rights of “teachers who explore the ‘scientific strengths and scientific weaknesses’ of evolution and climate change.”37
Figuring out how to demarcate between science and nonscience is no laughing matter. Being able to say, in public and in a comprehensible way, why science is special seems a particular duty for those philosophers of science who believe in science, but have not been able to articulate why. As climate change deniers begin to gear up, taking a page from the earlier battles of the creationists (and the tobacco lobby) in fighting scientific conclusions that they don’t like through funding “junk science,” then spreading it through public relations, isn’t it time that we found a way to fight back?
Of late, this is precisely what has happened. In 2013, philosophers Massimo Pigliucci and Maarten Boudry published an anthology entitled Philosophy of Pseudoscience: Reconsidering the Demarcation Problem, in which they self-consciously seek to resurrect the problem of demarcation thirty years after Laudan’s premature obituary. The papers are a treasure trove of the latest philosophical thinking on this issue, as the profession tries to steer its way out of the ditch where Laudan left it: where we believe that science is special, but can’t quite say how. It is disappointing—but certainly understandable—that after all this time philosophers are a little unsure how to proceed. Perhaps resurrecting the traditional problem of demarcation is the answer. Or perhaps there is another way.
It is no small thing to dismiss the problem of demarcation, which has been the backbone of the philosophy of science since its founding. The attractiveness of using its structure and vocabulary as a way to understand and defend the distinctiveness of science is obvious. Perhaps this is why virtually all previous attempts to say what is special about science have involved trying to come up with some criterion of demarcation. But there are many pitfalls to resurrecting this approach.
In Pigliucci’s essay “The Demarcation Problem: A (Belated) Response to Laudan,” he rejects the “necessary and sufficient conditions” approach, preferring instead to rely on Ludwig Wittgenstein’s concept of “family resemblance.” Pigliucci thus claims to rescue the problem of demarcation from Laudan’s “old-fashioned” approach (which may be conceived of as challenging Laudan’s “meta-argument” over what is required to solve the problem of demarcation).38 Instead Pigliucci’s idea is to treat learning the difference between science and pseudoscience as a kind of “language game,” where we c
ome to learn the clusters of similarity and difference between different concepts by seeing how they are used. The goal here is to identify the various threads of relationship that do not fall neatly along the lines of necessary and sufficient conditions but nonetheless characterize what we mean when we say that some particular inquiry is scientific. Two of these threads—“empirical knowledge” and “theoretical understanding”—appear to do most of the work. As Pigliucci writes, “if there is anything we can all agree on about science, it is that science attempts to give an empirically based theoretical understanding of the world, so that a scientific theory has to have both empirical support and internal coherence and logic.”39 As a result, Pigliucci thinks that—among other things—we will have discovered a “Wittgensteinian family resemblance” for the concepts of science and pseudoscience that provides a viable demarcation criterion to “recover much (though not necessarily all) of the intuitive classification of sciences and pseudosciences generally accepted by practicing scientists and many philosophers of science.”40
This account, however, seems quite nebulous as a criterion of demarcation. For one thing, what is its logical basis? At various points Pigliucci refers to the use of “fuzzy logic” (which relies on inferring degrees of membership for inclusion in a set) to help make his criterion more rigorous, but it remains unclear how this would work. As Pigliucci admits, “for this to actually work, one would have to develop quantitative metrics of the relevant variables. While such development is certainly possible, the details would hardly be uncontroversial.”41 To say the least: one imagines that the central concepts of empirical knowledge and theoretical understanding may be equally as difficult to describe and differentiate from their opposites as the concept of science itself. Has Pigliucci solved the problem of demarcation or merely pushed it back a step?
