In the wake of Popper’s failure, many philosophers of science concluded that the demarcation problem is unsolvable: there simply is no set of features shared by all and only the sciences, so there can be no principled answer to the question of what counts as “science” and what doesn’t. In an influential essay titled “The Demise of the Demarcation Problem” (1983), philosopher of science Larry Laudan argued that the demarcation problem is not only unsolvable but also philosophically unimportant. The reason people are interested in labeling certain hypotheses “scientific,” he observes, is that they think the label gives special credibility to a hypothesis or theory. However, as Laudan points out, that’s a naïve mistake: not all scientific theories are well-supported by evidence. It goes without saying, moreover, that many non-scientific claims are strongly supported by evidence. (For example, the claim that I have four children is not a scientific hypothesis, yet I have overwhelming evidence that the claim is true.) The more important question is whether we have good reasons to believe a claim, not whether the claim meets some arbitrary criteria for being labeled “scientific.” Laudan concludes:
If we would stand up and be counted on the side of reason, we ought to drop terms like ‘pseudo-science’ and ‘unscientific’ from our vocabulary; they are just hollow phrases which do only emotive work for us. … [Instead,] our focus should be squarely on the empirical and conceptual credentials for claims about the world. The ‘scientific’ status of those claims is altogether irrelevant.Larry Laudan, “The Demise of the Demarcation Problem,” in R. S. Cohen and L. Laudan (eds.), Physics, Philosophy and Psychoanalysis: Essays in Honor of Adolf Grunbaum (Boston: D. Reidel Publishing Company, 1983), 125.
Laudan’s assessment of the demarcation problem has been the consensus view among philosophers of science for several decades. However, recent years have seen a revival of interest in the demarcation problem.For further discussion of recent developments, see the Stanford Encyclopedia of Philosophy entry on Science and Pseudo-Science and the Internet Encyclopedia of Philosophy entry on Pseudoscience and the Demarcation Problem. Though contemporary philosophers generally agree with Laudan’s point that the boundary between science and non-science doesn’t correspond to any distinction between positive and negative epistemic status, many argue that the boundary is nonetheless important for social and political reasons. For example, policy decisions about what to include or exclude from public science education depend on a line of demarcation. Even if Laudan is right that any such line must be arbitrary, a decision about where to place the line merits careful consideration because of its practical import. The political and ethical consequences of public policies must be taken into account when deciding what to include, for political purposes, in the category of genuine science. Thus, perhaps, demarcation should be viewed as a political or even a moral issue, rather than an epistemological one.
I’ll leave debates about public policy to others. Since politically-motivated demarcation criteria have little to do with the relationship between faith and science, those political debates are tangential to the aim of this book. For present purposes, let’s follow Laudan’s advice and focus on the crucial issue he identifies: “the empirical and conceptual credentials for claims about the world.” How can we tell whether a hypothesis—scientific or otherwise—is well-supported by evidence? What kinds of explanations do we have most reason to believe? What methods, procedures, or strategies should we employ if we want to discover and understand more about the world? Clearly, the progress and successes of the natural sciences have something to teach us about these philosophical questions, even if the answers won’t provide any tidy solution to the demarcation problem.
Demarcation efforts have failed to identify any one scientific method that is both unique to science and characteristic of all scientific research, but our survey of the problem was not in vain. Several important philosophical issues emerged in the preceding discussion, which will serve as the conceptual backdrop for the remaining sections of this chapter. For example, we have already glimpsed the intricacy of scientific methodologies. A plurality of distinct but interrelated methods are employed, to varying degrees, in diverse scientific disciplines. Scientific methods are a lot messier—but also more interesting—than simplistic theories of demarcation have led many people to believe. In the next section, we’ll take a closer look at two methods that appeared in the foregoing discussion: the H-D method and the method of inference to the best explanation.