Stud. Hist. Phil. Sci., Vol. 31, No. 2, pp. 249–267, 2000 Pergamon 2000 Elsevier Science Ltd. All rights reserved. Printed in Great Britain www.elsevier.com/locate/shpsa 0039-3681/00 $ - see front matter A Pragmatic Approach to the Demarcation Problem David B. Resnik* The question of how to distinguish between science and non-science, the so-called ‘demarcation problem’, is one of the most high-profile, perennial, and intractable issues in the philosophy of science. It is not merely a philosophical issue, however, since it has a significant bearing on practical policy questions and practical decisions. This essay develops a pragmatic approach to the demarcation problem: it argues that while there are some core principles (or criteria) that we can use in distinguishing between science and non-science, particular judgments and decisions about some- thing’s scientific status depend, in part, on practical goals and concerns. 2000 Elsevier Science Ltd. All rights reserved. 1. Introduction The question of how to distinguish between science and non-science, the so- called ‘demarcation problem’, is one of the most high profile, perennial, and intrac- table issues in the philosophy of science. Writing in the spirit of logical positivism, Karl Popper (1963) offered the most famous solution to the problem when he argued that scientific theories and hypotheses must be testable. Subsequent writers, such as Kuhn (1962, 1970), Ziman (1968), Lakatos (1977), Feyerabend (1975), Thagard (1978, 1988), Kitcher (1983, 1993), Dupre´ (1993), Ruse (1982) and Lau- dan (1982) have criticized Popper’s definition of ‘science’ and have offered their own definitions. While there is no shortage of approaches to the demarcation prob- lem, it is not at all clear that philosophers of science have ‘solved’ it. Indeed, some writers have concluded that it is impossible to draw a clear and definite line between science and non-science; the best we can do is make a list of criteria that apply to most of those enterprises that we call scientific (Dupre´, 1993; Kitcher, 1993). The demarcation problem is not merely a philosophical issue, however, since it has a significant bearing on practical policy questions, such as public education, the safety of foods and drugs, the use of scientific testimony in the courtroom, and * Department of Medical Humanities, East Carolina University, School of Medicine, Greenville, NC 27858-4354, U.S.A. (e-mail: [email protected]). Received 1 March 1999; in revised form 17 September 1999. PII: S0039-3681(00)00004-2 249 250 Studies in History and Philosophy of Science the funding of research. Real people face this problem every time they decide whether creation science should be taught in public schools, whether recovered- memory testimony should be allowed in the courtroom, whether a health insurance company should pay for a visit to the chiropractor, whether the National Institutes of Health should fund research on acupuncture, or whether a new bridge design will hold its intended load. For better or worse, policy makers, politicians, attorneys, judges, physicians, engineers, educators, and lay people must distinguish between genuine science and non-science when making practical decisions. The world cannot wait for philosophers of science to solve the demarcation problem. Thus, there are actually two demarcation problems, the philosophical problem and the practical one. Recognizing that there are two problems raises some difficult questions about their relationship (if any): should philosophical solutions be shaped by practical concerns? Should the difference between science and non-science depend on who asks the question? Why do people care about separating science from non-science? This essay will address these issues by developing a pragmatic approach to the demarcation problem. It will argue that while there are some core principles (or criteria) that we can use in distinguishing between science and non- science, particular judgments and decisions about something’s scientific status depend, in part, on practical goals and concerns. Giving a satisfactory answer to the question ‘what is science?’ depends, in part, on knowing who asks the question and why. My defense of this view will proceed as follows. Section 2 contains some pre- liminary remarks about defining the words ‘science’ and ‘scientific’. Section 3 gives an overview of failed attempts to solve the philosophical demarcation prob- lem, Section 4 diagnoses these problems, and Section 5 discusses how demarcation issues can arise in practical settings. Section 6 synthesizes the discussion in Section 2 through Section 5 by developing a pragmatic approach to demarcation, and Sec- tion 7 addresses two objections to this approach. 2. Defining the Terms ‘Science’ and ‘Non-science’ 2.1. Demarcation as a normative issue The demarcation problem is a classic definitional or ‘what is it?’ question in philosophy. In thinking about this aspect of the problem, we need to recognize that there are different types of definitions. Descriptive definitions attempt to capture (or accurately describe) common (or specialized) meanings and uses of words. A descriptive definition of ‘science’ is what one might find in a dictionary, lexicon, or glossary. Linguists, cultural anthropologists, and other social scientists attempt to provide descriptive definitions. Prescriptive definitions, on the other hand, make recommendations for how we ought to use words. These definitions are based not on a description of usage but on deeper theories that explicate or analyze words. Analytic philosophers, for the most part, have concerned themselves with explicat- A Pragmatic Approach to the Demarcation Problem 251 ing and analyzing terms, instead of merely describing common (or specialized) usage (Gorovitz et al., 1979). For example, philosophical definitions of ‘knowl- edge’ are usually based on epistemological theories, not on common usage. In this essay, I will understand philosophical and practical demarcation problems to be about how we ought to use words. Whether the question is raised in a court of law or in a classroom, the question ‘what is science?’ is primarily an inquiry into how we ought to use the terms ‘science’ and ‘scientific’. If one views it this way, the demarcation problem has inherent normative dimensions. Indeed, the nor- mative aspects of the question can readily be seen when we apply the words ‘science’ and ‘scientific’. We often use the term ‘scientific’ to assert the value, merit, or worth of some thing. We often use the word ‘unscientific’ by contrast, to assert that something lacks worth or value. Thus, ‘science’ and ‘scientific’ are words we use in various kinds of appraisal, criticism, and evaluation (Kitcher, 1992). We use these terms in making both epistemic and practical value judgments. Epistemic value judgments pertain to the epistemic merit, legitimacy, or worth of theories, hypotheses, beliefs, methods, or concepts (Kitcher, 1992). To say that a theory is scientific, in this sense, is a way of saying that it has evidential support or credibility. To say that a theory is unscientific is often a way of saying that it lacks evidential support or credibility. For example, the question concerning the scientific status of the claims of astrology, one might argue, has a direct bearing on its epistemic legitimacy: if astrology is not a science, then it lacks epistemic legitimacy. By contrast, to claim that a discipline, such as economics, is a science, amounts to asserting that its theories, methods, and concepts have epistemic war- rant. Practical value judgments, on the other hand, pertain to the practical, e.g. moral, political, legal, social, legitimacy or worth of theories, hypotheses, beliefs, methods, or concepts. To say that a theory is scientific, in this sense, is a way of saying that it ought to be used or may be used in a particular context for a particular purpose. The terms ‘science’ and ‘scientific’ are often used to endow items with moral, legal, political, or social legitimacy, praise, or approval (Feyerabend, 1975; Long- ino, 1990). Thus, scientific medicine can be used to treat illnesses, but unscientific medicine should not be used (Angell and Kassirer, 1998); scientists can serve as expert scientific witnesses, but non-scientists or pseudoscientists should not be used in this fashion (Huber, 1991); and scientific theories about human origins can be taught in public schools, but unscientific theories should not be taught (Laudan, 1982). These remarks should not be taken to imply, of course, that all and only scientific theories, hypotheses, beliefs, methods, or concepts should be believed or used for practical purposes. One might have good reasons for refusing to believe some scientific statements, and one may have good reasons for believing some non- scientific statements. For example, science tells us that there is very little chance 252 Studies in History and Philosophy of Science that a person survives death, but a person may refuse to believe this statement in order to have hope or comfort in dying. A person may be justified in believing that he is a good poet, even if this claim has no scientific basis, since holding this belief may give him pleasure or enhance the meaningfulness of his life. It is also often appropriate to use some unscientific theories to achieve practical goals or refrain from using scientific ones. For example, in deciding whom to marry, it may be appropriate to use a non-scientific method, such as a ‘gut feeling’, and it may be inappropriate to use a scientific method, such as a blood test. One can recognize the epistemic and practical worth of scientific theories, concepts, methods, and hypotheses without succumbing to closed-mindedness and scientism. 2.2. Sorting through the variety of terms and phrases Since people who discuss the demarcation problem use a variety of terms and phrases, it is important to sort through the various expressions that have been employed. Our first point should be to distinguish between the noun ‘science’ and the adjective ‘scientific’.