Hard and Soft Science: Physics Vs. Psychology
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THINKING ABOUT SCIENCE MASSIMO PIGLIUCCI Hard and Soft Science: Physics vs. Psychology hile doing research for my results from physics experiments are things: on the one hand, one could next book on the differ- “better” than results from psychological examine theoretical cumulativeness, W ences among so-called hard experiments. But better in what sense? i.e., the advancement of a scientific science, soft science, and pseudoscience, Hedges thought that the difference field in terms of how well its theories I came across a little-known study pub- between the two sciences should be account for how the world is. For lished in 1987 by Larry Hedges, then evident in the “cumulativeness” of their instance, astronomy advanced by a giant at the Department of Education at results: physics should be making prog- leap when it abandoned the Ptolemaic, the University of Chicago. Hedges was ress more steadily and at a faster pace earth-centered view of the solar system empirically addressing the sort of ques- than psychology. This is an important in favor of the Copernican, sun-cen- tion that is usually left to a philosopher criterion because lack of progress, i.e., tered system. Then it made smaller of science: if it is true—as it is often lack of cumulative results over time, but significant advances by realizing claimed—that physics (the queen of the is one of the distinctive features of that the planets move in elliptical, not It turns out that the replicability of research findings in psychology (and therefore, presumably, the resulting empirical cumulativeness of that discipline) is no worse (or better) than the replicability of findings in particle physics. hard sciences) “performs” much better pseudoscience. For instance, the idea of circular orbits; by discovering that the than psychology (arguably the Cin- intelligent design in biology has made sun is only one star among billions in derella of the soft sciences), one ought no progress since its last serious articu- the Milky Way; and finally by placing to be able to show, data in hand, that lation by William Paley in 1802. Com- our galaxy itself as only one of billions Massimo Pigliucci is professor of evolu- pare that to the stunning advances in existing in the universe. Judging theo- tionary biology and philosophy at Stony the field of evolutionary biology since retical cumulativeness, however, is not Brook University in New York, a fellow of Darwin’s publication of On the Origin simple, as it involves a degree of subjec- the American Association for the Advance- of Species in 1859, and one has a good tivity, and—more crucially—it requires ment of Science, and author of Denying picture of the difference between science a long historical perspective. Psychology Evolution: Creationism, Scientism and and pseudoscience. is a relatively novel science, and it would the Nature of Science. His essays can be As Hedges immediately recognized, therefore be rather unfair to compare its found at rationallyspeaking.org. however, cumulativeness in science theoretical advances with those of mod- can mean two very distinct, if related, ern physics or astronomy, which have 28 Volume 33, Issue 3 SKEPTICAL INQUIRER had a much longer history. de la crème in physics research) as well at estimating the mass of two funda- What then? Hedges opted for a more as in a variety of psychological fields, mental particles, the electron and the tractable measure of progress, focusing including studies of sex differences, of proton. These are two of the best- on empirical cumulativeness. The idea is students’ ratings of teaching, of the effect known and best-studied particles, so one that if physics, psychology, or any other of racial desegregation programs, and would expect a high degree of congru- science is really successful at describing others meant to provide a range from ency among the outcomes of different the world as it is, then at a minimum quasi-hard psychology (sex differences) experiments. Alas, this was not the case: its empirical results (from observation to as-soft-as-it-gets research (desegrega- experiments performed over a period of or experiment) ought to be consistent tion studies). He used standard statistical years (from the early 1960s through the from one publication to another. To put tools to tabulate and compare the results mid-1970s) clearly show that the vari- it simply, if Earth is really round with a of a variety of studies published over ous estimates were not consistent with diameter of about 12,700 kilometers, a period of years in several specialized each other and their confidence intervals the different methods to estimate its journals. often did not overlap, meaning that the shape and size ought to yield approxi- The results were rather stunning. It results were significantly different from mately the same result. If it turns out turns out that the replicability of research each other statistically. that some measurement gives us 3,000 findings in psychology (and therefore, Data like these, of course, should kilometers while others go up to as presumably, the resulting empirical not be interpreted as indicating that much as 100,000 kilometers, then there cumulativeness of that discipline) is no physicists have no idea what the mass is something seriously wrong with the worse (or better) than the replicability of of the electron or the proton is. For one way we do the measurements. Again, findings in particle physics. As Hedges thing, we now have many more experi- the comparison with pseudoscience is put it: “What is surprising is that the ments, and their results are much more obvious: some creationists, for instance, research results in the physical sciences are consistent. Moreover, it’s not like the believe that Earth is about 6,000 years not markedly more consistent than those estimates reported by Hedges show the kind of huge variation that would make old, while others accept the geological in the social sciences. The notion that anyone seriously question fundamental figure of four billion years, give or take. experiments in physics produce strikingly aspects of nuclear physics. But the point This is a staggering discrepancy of five consistent . results is simply not sup- orders of magnitude, which betrays the remains that even the queen of science ported by the data.” sometimes gets things wrong over a fact that creationists really have no idea It also turns out that some of the period of many years, and the quintes- how old Earth is or how to measure it; results in physics are much less reliable sential example of soft science, psychol- in turn, this is yet another indication than one would think. For instance, ogy, actually displays a remarkable and that creationism is no science. Hedges compared the data obtained surprising degree of consistency in its So Hedges went about sifting the during two series of experiments aimed results. That’s something you can quote literature in particle physics (la crème July 6–12, 2009 Holland, NY Come think, question, and grow in this week-long summer camp experience. We share with campers the memorable and fun summer-camp experiences of roasting marshmallows, outdoor experiences, and unforgettable friendships while promoting rea- son, critical thinking, character development, and a skeptical humanist perspective. Through inquiry-based, hands-on experiments, activities, and discussions, campers will experience just how challenging, fascinating, and fun exploring the world and expanding the mind can be. Develop lifelong skills. Make lifelong friends. Opportunities for junior counselor and volunteer positions available. For more information, e-mail [email protected] or visit our Web site: www.campinquiry.org SKEPTICAL INQUIRER May / June 2009 29.