Picking a Bone with Philosophers of Science
Is science a value-free, "Dragnet" quest for "just the facts, ma'am," or is it an ideology or world view and, therefore, no more objective than any other belief system? How can scientific claims be evaluated? Are there right and wrong answers or merely value judgments and opinions? And what role does the personality of the scientist play in the march of scientific progress?
Creationists have now found a book that some claim demonstrates the fallibility of science and, in particular, of paleoanthropology. Bones of Contention: Controversies in the Search for Human Origins is a historical account of twentieth-century paleoanthropology—of the personalities of the major human-fossil hunters and the "bones of contention" that shaped their understanding of human prehistory. The book's author, Roger Lewin, editor of "Research News" for Science magazine, is a skillful and knowledgeable journalist with a Ph.D. in biochemistry from Liverpool University. He has intimate knowledge of the personalities and data involved, having written seven books on the subject of evolution (including three with Richard Leakey), as well as having covered newsworthy events in paleoanthropology for Science over a number of years. Bones of Contention is a highly readable antidote to dry, clinically detailed stories that portray scientists as impossibly "perfect" eunuchs. It consists largely of interviews with many of the leading lights of paleoanthropology in the English-speaking world. It is interpretive and thematically organized—not merely "gossip." And one of its main themes is that paleoanthropology is "storytelling."
Opening and closing with chapters on the nature of science, the book is structured in two-chapter dyads presenting first a controversy and then its resolution. These include the taxonomic status of the Taung child, the establishment and dethroning of Ramapithecus as the earliest human ancestor after the divergence of human and African ape lineages, the debate over the age of the KBS tuff and its associated fossil hominid, and the significance of "Lucy" (Australopithecus afarensis) in human evolution.
The book argues that a priori conclusions have played a major role in shaping the results of empirical research in paleoanthropology, and that paleoanthropologists are particularly susceptible to hero-saga storytelling and contentiousness. Rich in lively historical anecdotes, Bones of Contention is similar to Stephen Jay Gould's Mismeasure of Man in its focus on how unconscious biases dictate the results of empirical, presumably "objective" research. Lewin's book goes further, however, in suggesting that the various misinterpretations of Ramapithecus can be equated with Piltdown Man—a hoax!—and that paleoanthropology is, "within the province of ideology and religion, broadly defined" (p. 302, quoting leading anatomist and paleoanthropologist Matt Cartmill). So it is hardly surprising that this book has been well received by creationists; it inadvertently provides grist for their antievolution mill. "You often see what you expect to see," says Lewin, "and not what you don't" (p. 19).
Lewin endorses the conceit, currently popular among philosophers of science, that science is really "storytelling" or "mythmaking." However, buried deep near the end of his text (p. 318) is Cartmill's definition of myth as story whether true or false. Many readers will miss the subtlety and take myth to mean an invented story rather than one which is verifiable or falsifiable. And Lewin himself is not the relativist his "myth" theme suggests; with twenty-twenty hindsight in chapter after chapter, he establishes how once-powerful "wrong" ideas have been overthrown by heroes with "right" ideas. This is suspiciously similar to the notion of good old-fashioned, self-correcting, positivistic science. Is science mythical or logical? The author seems to support both opinions.
Because of this contradiction, Bones of Contention can be read very differently by different readers. Although Lewin details the historical brawls and exposes the brazen defenders of mistaken ideas, his book nevertheless reveals a stunning accumulation of knowledge concerning the course of human evolution. So, some people will read the book as a chronicle of how science operates to weed out wrong ideas (for example, Osmon, 1988), while others, including creationists, will read it as a cutting expose of paleoanthropology as fantasy. Still others, such as Colin Groves in the Journal of Human Evolution (1988), see the book as insightful journalism revealing the pitfalls of science in action, while Jon Marks, in the same volume (1988a), describes Lewin's interpretation of the history of paleoanthropology as "extremely whiggish, all characters being judged according to how like our own their views turn out to have been in retrospect" (p. 267).
Lewin portrays paleoanthropology as less objective than other sciences (such as his own field, biochemistry). His closing observation is that "all sciences are odd in some way, but paleoanthropology is one of the oddest" (p. 319). Ironically, the research of two of Lewin's "heroes"—molecular biologists Charles Sibley and Jon Ahlquist—purporting to clinch once and for all (and without fossils!) the debate over chimp-gorilla-human-orang relationships, is now under attack for some of the same reasons that Lewin uses to dismiss arguments based upon fossil evidence: a priori bias and failure at objectivity (Marks, 1988b).
Despite Lewin's damning portrayal of some scientists as dogmatists refusing to change their arguments despite overwhelming contradictory evidence, his quotations do not always support his own analysis. He portrays Elwyn Simons, the world-renowned paleontologist, as an indefatigable defender of the notion that Ramapithecus was a direct Miocene ancestor of Australopithecus and Homo. Simons is nevertheless quoted as saying, upon seeing new materials belonging to a Miocene hominoid genus closely related to Ramapithecus, "We all knew what that meant." What "that meant" was that this genus, Sivapithecus, and probably Ramapithecus as well are more closely related to the Asian orangutan than to either humans or African apes. Given this admission, Simons hardly qualifies as a bastion of dogmatic prejudice; at most, he merely held on too tightly and too long to the idea of Ramapithecus as a direct human predecessor. Lewin attributes this to wishful thinking and unconscious bias divorced from the data on which his argument hung. Simons sees it otherwise; his early interpretation of Ramapithecus, he says, was the best possible interpretation of the empirical data then available. His position changed as new empirical data rendered his hypothesis untenable. This is the way science is supposed to work.
It is true, of course, that the personalities of scientists affect the changing dogmas of science; that individuals—hating to be proven wrong—sometimes defend favorite positions too long; and that science cannot claim to be the paragon of "truth." But scientists do embrace the notion that hypotheses should be empirically tested and rejected if the evidence shows that they don't work. Self-criticism is the professed backbone of scientific ideology.
Science is neither value-free nor fact-free. Science is a human enterprise and, as such, can never be value-free. And although hypotheses may not always be inescapable conclusions driven by data—there are usually too many explanations available that could reasonably account for the same data—they still must at least be nudged by the data to be considered scientific. All explanations are not equal. Like science in general, paleoanthropology is storytelling, but it is not merely storytelling.
In Betrayers of the Truth, journalists William Broad and Nicholas Wade (1982) grapple with the same basic issues: the crippling power of a priori convictions, prejudice, and ambition in the practitioners of science versus the enlightening power of empirical hypothesis testing. Idealistic philosophical realists might portray science as objective, unencumbered by bias, and motivated solely by the search for truth, while cynical philosophical relativists might insist that objectivity never prevails in science; instead, one explanation is simply replaced by another, with no objective criterion guiding the choice of either one. Both views of science, in their extreme forms, are naive.
The authors of Betrayers of the Truth offer a third view. Scientists may work selfishly for their own aggrandizement, using whatever rhetorical techniques are most likely to be persuasive, but the "invisible boot" (the scientific analogue of economist Adam Smith's "invisible hand" that works to produce public good out of private greed) will kick out explanations that really don't work. Over time, the selfishness of individual scientists inadvertently works toward benefiting science as a whole. Individual motives need not be wholesome; methods need not be objective. But, despite any lack of objectivity in the process of science, objectivity seems to prevail in the long run.
Although Bones of Contention is a fascinating and factual—if contentious—account of the history of paleoanthropology, it will surely be misused by people who wish to portray the fact of human evolution itself as fancy. But Lewin could not have written a Bones of Contention about "creation science"—not because "creation science" lacks storytelling (it most certainly does not!) but because there are so few controversies there! There are precious few bones of contention among creationists and virtually no resolutions nudged by the discovery of new empirical evidence. Like the religion behind it, creationism seeks to be "the same—yesterday, today, and forever."
Broad, William, and Wade, Nicholas. 1982. Betrayers of the Truth. New York: Simon and Schuster, Inc.
Groves, Colin. 1988. Review of Bones of Contention: Controversies in the Search for Human Origins. Journal of Human Evolution. 17:270-273.
Marks, Jon. 1988a. Review of Bones of Contention: Controversies in the Search for Human Origins. Journal of Human Evolution. 17:267-270.
——. 1988b. "DNA Hybridization: Holy Grail or Golden Calf?" Paper presented to the fifty-seventh annual meeting of the American Association of Physical Anthropologists in Kansas City, MO (March). Abstracted in American Journal of Physical Anthropology, 75:2:245-246.
Osmon, Philip. 1988. Review of Bones of Contention: Controversies in the Search for Human Origins. Creation/Evolution Newsletter. 8:2:18-20.