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The controversy over evolution is at bottom not a dispute about evidence, but a dispute about whether words like “evolution” should be defined precisely and used consistently, and about whether a scientific conclusion is indisputably correct if it is endorsed by a consensus of contemporary scientific authorities. That is why I thought it appropriate for a law professor to take a professional interest in biological evolution, since lawyers are trained to insist that terms in a legal document be precisely defined, and are taught to check any consensus judgment of experts against the primary evidence.
Examples of vague or slippery definitions and appeals to the authority of consensus abound in writings about evolution, especially those writings that urge potentially skeptical people to trust the experts, rather than to examine the evidence for themselves.
The Christian geneticist Francis Collins, in his much-acclaimed book, The Language of God, describes the human genome in terms that seem at first to imply that its design is the product of intelligence. At the outset, Collins reverently talks of the partial sequencing of the human genome as providing “a glimpse of our own instruction book, previously known only to God.” In our experience, instruction books are written only by intelligent agents.
Evolutionary biologists tell us, however, that this remarkably complex instruction book, written with a billion chemical letters in a fantastically ingenious code, is the product, not of God’s intelligence, but of the mindless accumulation of random mutations by natural selection (differential reproduction). Collins agrees with the evolutionary biologists, relegating God to the more distant role of fine-tuning the cosmos so that we could evolve, and thinks that the rest of us should agree with them also. Yet he never says what evidence convinces him that the Darwinian mechanism has the creative power not only to write the instruction book, but also to evolve molecular machines that can understand the instructions and act upon them.
No Serious Scientist
Instead of providing the evidence, Collins invokes the authority of an expert consensus, writing that “no serious biologist today doubts the theory of evolution to explain the marvelous complexity and diversity of life.” He does not say what makes a biologist “serious,” although I sense that this is a matter of definition and hence, a tautology. No serious scientist publicly disputes a professional consensus, because those who dispute the consensus are not taken seriously.
The consensus in biology is that unintelligent material processes were capable of performing whatever feats of creativity needed to be performed in the history of life. Once the consensus is formed, it maintains itself. No reputable scientist ever disputes the consensus, because once-reputable scientists who dispute the consensus lose their reputations.
I am sure Collins sincerely means what he writes. He must be aware, however, that even the illustrious director of the Human Genome Project would soon find himself in professional disgrace if he were seen to be undermining the consensus, or even unwilling to defend it.
Of course, science by consensus is not confined to the subject of evolution. The authority of consensus is likely to be invoked whenever there is a dominant party in science that is absolutely certain that its viewpoint on a particular issue is correct and ought to be generally accepted. In such cases, it would be dangerous to allow an open debate with dissenters over the evidence, since any suggestion of division within the scientific community might encourage non-scientists to make up their own minds on important scientific questions, with potentially disastrous consequences. In such circumstances, a scientific community sometimes feels it must present a united front and must dismiss dissenting arguments as unworthy of consideration so they do not achieve the legitimization that comes from being debated.
This dynamic is evident today in the politicized subjects of global warming and AIDS. In the former case, the rationale is that any appearance of disunity in science might allow vacillating politicians to postpone taking the painful measures that are urgently needed to avert a global catastrophe. In the latter case, any appearance of doubt about the cause of AIDS might result in more people having “unprotected sex” or not taking the drugs that doctors who accept the consensus have prescribed for them.
On the other hand, if the consensus could be wrong, then excluding other ideas from consideration may produce its own disaster.
Science’s “Oath Helpers”
Rebecca Culshaw is a Canadian mathematician who is an assistant (untenured) professor at the University of Texas, Tyler campus. Her entire career has been devoted to making mathematical models of what newspapers call the “HIV/AIDS pandemic.” She publicly resigned from further research in this field when she became convinced that its fundamental premise is wrong. Fully aware that she was probably committing professional suicide, she authored a book against the HIV theory titled Science Sold Out.
This short book presents a devastating indictment of the lax scientific standards that produced and maintained the consensus that a specific retrovirus is the cause of AIDS. One chapter is titled “Science by Consensus.” The discovery of a virus said to be the “probable cause of AIDS” was announced at a press conference in April 1984, before any supporting papers had appeared in the scientific journals. Almost immediately, the “probable” was dropped, and the retrovirus became “the virus that causes AIDS” or simply “the AIDS virus.” The labels made dissent unthinkable, and hence invisible. No serious biologist would contend that the “AIDS virus” does not cause AIDS.
Long after the consensus had hardened, the president of South Africa became convinced that poverty rather than sex was the cause of his country’s health problem, and so became doubtful of the HIV theory. He announced a plan to convene a panel of scientists with diverse viewpoints to examine the evidence for and against the theory. This is the kind of scientific discussion that ought to have occurred before or instead of the 1984 press conference. But the time for free debate had passed. The HIV/AIDS research establishment scorned the panel and responded with a passionate affirmation of belief in the HIV theory—the Durban Declaration, signed by over 5,000 Ph.D. scientists, including Nobel prize winners.
This is reminiscent of the legal process of many centuries ago, when both the accuser and the accused made their cases with oaths, including the supporting oaths of “oath helpers,” who swore to their truthfulness. Nowadays we tell juries to consider only the evidence and to ignore any affirmations of belief by the advocates.
As a rule, scientists also insist that judgments be based on evidence rather than on affirmations of belief. On heavily politicized subjects, however, they sometimes decide that only the authority of professional consensus can protect us from the erroneous conclusions we might reach if we knew the whole story.