Today I attended a lecture by Massimo Pigliucci at Washington University in St. Louis. The title of the talk was “A Fresh Look at the Demarcation Problem and Why it Matters.” Pigliucci’s aim was to help us distinguish between real science and pseudoscience.
He offered some a few examples up front to set the stage. It is fairly well accepted these days that Freudian psychoanalysis is pseudoscience whereas Einstein’s theory of relativity is a prototypical example of legitimate science. Most science falls in between these endpoints. One example of a suspect science is string theory, which Pigliucci characterized as a favorite modern day “whipping boy.”
Karl Popper had the same objective back in the 1930s, offering his falsifiability approach: a theory should be considered scientific if, and only if, it is falsifiable. Not only did Popper believe that he had provided a method for determining what is truly scientific; he also believed that he had solved David Hume’s “problem of induction.” Induction is the process of generalizing from a smaller set to a larger as-yet-unobserved set; the induction problem, according to Hume, was that we cannot rationally justify induction, because this conclusion depends upon the assumption that nature will continue to be uniform. Pigliucci argued that Popper’s falsification approach is not sufficient for it distinguishing between pseudoscience and science, because it is “vulnerable to the Duhem-Quine theses.” The problem, according to Pigliucci, is that one can often save a falsifiable hypothesis by tweaking it (as nineteenth century astronomers did when they worked to save Newtonian physics in light of the perturbations of Mercury by positing that there was an as-yet-unseen planet closer to the sun, a planet they named “Vulcan.” It would also seem that there is another problem with falsifiability; some nascent fields don’t yet have a thick collection of observations with which to work. Imagine that Aristotle announced the theory of general relativity, far before Einstein. It might have been impossible for him to offer a way to falsify his theory back then, but not because there was any problem with the theory itself; it would thus be declared to be not-science. Pigliucci addresses this situation (see below).
Throughout his lecture, Pigliucci referred to Larry Laudan’s approach to the demarcation problem. Laudan has argued that the demarcation problem is “uninteresting and intractable,” urging that we should completely stop using terms like “pseudoscience” and “unscientific.” Laudan argues that philosophers have failed to point out necessary and sufficient criteria for distinguishing between pseudoscience and science. He therefore considers the demarcation project doomed. Pigliucci disagrees, pointing out that it is not necessary to find necessary and sufficient criteria for distinguishing between science and pseudoscience. Pigluicci draws upon Wittgenstein’s work on family resemblances. Wittgenstein had challenged people to define the word “game” in terms of necessary and sufficient conditions. It seems like an easy task, but it is not. Pigliucci refers to this exercise as “humbling.” Just because we can’t set out the necessary and sufficient conditions doesn’t mean we don’t know what a “game” is. With regard to many concepts, including “species,” and, yes, “science,” no boundaries have been drawn, yet we have workable ideas for what these concepts are. Wittgenstein’s observations have been recognized and expanded by modern linguists, including George Lakoff, who has labeled such concepts as “radial categories,” indicating that prototypes serve as the most typical instances of such categories. And see here and see this example regarding the word “mother”:
Radial categories are categories motivated by conventions, but not predictable from rules. The concept of “mother”, for example, may be explained in terms of a variety of conditions that may or may not be sufficient. Those conditions may include: being married, has always been female, gave birth to the child, supplied half the child’s genes, is a caregiver, is married to the genetic father, is one generation older than the child, and is the legal guardian. Any one of the above conditions might not be met: for instance, a “single mother” does not need to be married, and a “surrogate mother” does not necessarily provide nurturance. When these aspects collectively cluster together, they form a prototypical case of what it means to be a mother, but nevertheless they fail to outline the category crisply. Variations upon the central meaning are established by convention by the community of language users.
Pigliucci explains that philosophers have much to add to this debate. They make progress (and Pigliucci emphasizes that philosophers actually do make progress) by starting out with an analysis of simple concepts, finding out what is wrong with those concepts, then moving to other better ways of expressing that concept. For example, Aristotle distinguished between know-how (craftsmanship) v. know-why (science). According to Pigliucci, Laudan would consider pre-Copernican astronomy to be a “craft,” rather than “science.” Pigliucci agrees: pre-Copernican astronomers did function more like craftsman than scientists. Pigliucci points out that Isaac Newton had quite a few nutty ideas to go with those of his ideas which were great. He did not use what is now considered to be the scientific method with regard to much of his work. Back in the 1700s, everything was pre-science. In fact, the word “science” did not refer to the modern concept of science until the 1840s. Science is constantly evolving, which is one reason why it is impossible to find necessary and sufficient conditions with which one can identify science.
On a side note, Pigliucci whimsically asked why we refer to Newton and Galileo as we do. To be consistent, we should always use the first name only or the last name only: we should call them “Isaac” and “Galileo,” or “Newton” and “Galilei.”
Pigliucci raised the topic of the “Pessimistic Induction Theory,” the idea that all induction theories developed so far have failed, therefore none are true, even the ones on which we rely today.
Larry Laudan argues that the history of science is a “graveyard” of once empirically successful theories whose central terms have been found not to refer.
Again, Pigliucci stresses that we do have progress. For instance, philosopher John Stuart Mill offered five methods of scientific induction, which represented progress. Also consider the logical positivists, whose approach failed because it is circular (one would need to verify the verification theorum). Nonetheless, logical positivism was an improvement over all that had come before.
Laudan argued that we should quit labeling the methods of knowing we don’t like to be pseudoscience, because this is a corrupt approach. Pigliucci agrees with some of Loudoun’s concerns, but argues that Louden’s concerns are not fatal to the demarcation project. Both Laudan and Pigliucci agree that we must be able to state our conditions of adequacy for a demarcation theory. This can be done, argues Pugliucci, in large part by deferring to what the scientists recognize as science. Yes, there will be disagreements, but there will also be substantial consensus. Again, we need to take seriously what the scientists themselves consider to be science, though this does seem to invite circular thinking (because we need to somehow define who qualifies as “scientists”). Pigliucci believes there is a well enough accepted continuum ranging from pseudoscience to proto-science to soft science to science. It is not a perfect or simple solution, but he reminds us that interesting problems seldom lend themselves to simple clear-cut treatments–there is no need to demolish the entire project just because we can’t think of necessary and sufficient conditions for what constitutes “science.” Equally important, Pigliucci warns that “we can’t afford to throw out science that is useful” (and there is a lot of it) just because we cannot perfectly define it.
There are serious social and political implications for staying with the demarcation project. These implications are illustrated by the Dover trial, where the judge listened to two philosophers of science prior to ruling that intelligent design is not scientific.
At this point in his presentation, Pigliucci presented a graph with two axes (I’ve sketched out a simplified version of his chart below). The X axis is a measure of theoretical understanding and the y-axis is the amount of empirical knowledge. Into this graph Pigluicci plotted various candidates. The bottom left corner contains pseudoscience is (such as HIV, Denialism, astrology and intelligent design). These are there because they lack and their radical understanding (into this group, I would love to add homeopathic medicine). Into the upper right corner he plotted bona fide sciences, such as particle physics, evolutionary biology, molecular biology and climate science. These have ample amounts of empirical knowledge and their radical understanding. The upper left corner contains psychology, economics and sociology (lots of comparable knowledge, but less than optimum amounts of their radical understanding). Finally, the lower right corner contains candidates that have considerable theoretical understanding, but less than optimal in empirical knowledge: evolutionary psychology, SETI (search for extraterrestrial intelligence) and string theory.
In the question-and-answer phase of the lecture, Pigliucci drew considerable ire from one attendee for placing evolutionary psychology where he did (I sympathized with her viewpoint). Pigluicci indicated that evolutionary psychology is a sound theory supported by sketchy evidence. He emphasized that many practitioners are making wild conclusions based upon little to no evidence. The attendee retorted that he should not judge the entire field based upon some deficient scientists. Another audience member suggested that the search for the Higgs boson particle did not seem to be different than SETI (why are they in different quadrants?). Pigliucci disagreed, suggesting that the Drake equation is not a strong theoretical understanding, but rather a manner of calculating probabilities based upon no evidence at all (I found it so be a rather restricted view of evidence– Pigliucci seem to be limiting his evidence to the fact that no extraterrestrial life had yet been found. I think he should consider a wide variety of circumstantial evidence as well). Pugluicci stressed that he was not wedded to these positions—sciences evolve. Someday, we might have the necessary evidence to put more candidates into the top right quadrant.
Whereas Laudan argues that “pseudoscience” and “science” are hollow phrases, Pigliucci argues that these terms are “rich in meaning and consequences,” and he urged that both philosophers and scientists should get into the fray. In fact, as suggested above, the scientists will need to lead the philosophers in this endeavor.
Obviously, this topic could fill a semester-long course touching on related topics such as what constitutes an explanation. Pigliucci indicates that true explanations require a mechanism that allows scientists a way to develop and test hypotheses. On the other hand, as I have previously written, the answer might be simultaneously more simple and also more complex. Although many people have tried to dress up what constitutes an “explanation” in technical terms, I am not convinced that a test can be more effective than the following: An “explanation” is a description that makes you feel good. And then the devil is in the details, with better explanations consisting of more detail and better correspondence of a phenomenon with other phenomena. This approach, of course is not satisfying for those who want to draw a stark line separating science and pseudoscience.
I would add one more thing to this discussion: Pigliucci ends up looking to the scientists that help us decide what science is. This is quite similar to the approach taken by federal judges in American courts. What is known as the Daubert rule differs quite a bit to the scientists, to their journal publications, and to the acceptance in a scientific field of a particular theory that purports to be “scientific.”