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Copyright © Financial Times group | |
Stanford Professor of Biology Joan Roughgarden believes Darwin got it badly wrong on the laws of the species, and she's uniquely placed to put him right.
"If you have a theory that says something is wrong with so many people, then the theory is suspect," says Joan Roughgarden, looking up from her Caribbean chicken salad. "It is counter- intuitive that nature should have done such a bad job - or, if you prefer, that God should have made so many mistakes."
The theory in question is Charles Darwin's theory of sexual selection; the "mistakes" are homosexuals, bisexuals, transsexuals - anyone who does not fit into the neat categories of heterosexual male and female.
By challenging the great 19th-century naturalist, Roughgarden, a professor of biological sciences and geophysics at Stanford University, is making waves in academia and beyond.
The implications, not only for science but also for society, could be profound. After all, you don't need to be versed in the Origin of Species to share Darwin's twin assumptions that, broadly, the purpose of sex is reproduction and that females select mates on the basis of genetic characteristics or traits.
The snag, as Roughgarden points out, is that the Darwinian view includes no plausible explanation for homosexuality.
Since homosexual behaviour serves no evolutionary purpose it tends to get written off as an anomaly or unexplained mutation. This, she believes, is the unacknowledged root of so much prejudice against gays and lesbians.
"The silence of scientists on sexuality amounts to a cover- up," she says. "I'm not claiming that it is a deliberate cover-up, but studied silence contributes to the injustice that homosexual people encounter."
What better place to chew over the issues than San Francisco, the most liberal of US cities and focal point of a national debate over gay and lesbian marriage? We are eating at the bookshop-cum-cafe run by the Delancey Street Foundation, a non- profit organisation that offers work and training to ex-convicts and drug addicts. The room is bright, the service cheery and the food home-cooked: the salad for her, a spicy meatloaf sandwich for me.
Roughgarden, 58, lives nearby. These days she feels more at home in the city's cosmopolitan hubbub than at clean-cut Stanford University, 40 miles to the south. "There is a crisis of diversity at Stanford," she says as we wait for our order to arrive. "There is a relentless convergence of conformity that discourages diversity of viewpoint.
The education students are getting is not preparing them for the diversity that exists in the world." Her interest in diversity is more than academic. Until 1998, Joan Roughgarden was John Roughgarden. Her experience as a transgendered woman drives her campaign to show that, when it comes to sex and sexuality, Darwin was wrong.
Next month sees the European publication of her book, Evolution's Rainbow, the culmination of seven years' study, which spans natural history, human biology, anthropology and public policy. So how does Stanford's faculty view her challenge to Darwin? "You have to remember that these people are extremely smart," she says.
"They are also some of the most ambitious people on the face of the earth. If you are doing something outside the mainstream, they are more likely to ignore you than oppose you. Their errors are those of omission, not commission."
This sounds like the classic response to what Thomas Kuhn, the late historian of science, described as a paradigm shift.
In The Structure of Scientific Revolutions, his most famous book, Kuhn described a pattern by which believers in an established worldview - scientific or otherwise - tend to ignore evidence that runs counter to the prevailing orthodoxy.
The paradigm shifts only when someone - such as Copernicus, or, for that matter, Darwin - weaves the discounted evidence into a coherent alternative.
When it comes to sexuality, the natural reluctance of scientists to go beyond Darwin is compounded by the emotionally and politically charged nature of the debate.
While Roughgarden is never less than genial as a lunch companion, her strength of feeling is clear: "The fact that there is no coherent alternative position [to Darwin] means that pejorative claims go unrefuted. I feel that biologists have a responsibility to speak up."
Her alternative paradigm, presented in Evolution's Rainbow, starts with evidence that the natural world is more sexually diverse than usually appreciated. For example, about a third of the species of tropical fish swimming over coral reefs change sex at some point during their lifetime.
The conclusion, she says, is that our tendency to divide creatures into neat piles labelled "male" and "female" is mistaken. But surely, I interject, the male-female binary is a law of nature. It takes an egg and sperm to produce life, right?
"At a gamete level there is a clear binary. The mistake biologists make is to assume that because the egg and sperm are a binary that the whole body has to be a binary, whereas in fact the body is responding to a whole range of pressures and factors.
At the moment nobody - including me - has a theory for when a species should change sex. The trouble is that we now know a bunch of species that switch back and forth. There is no explanation. No explanation! Biologists are out of ideas."
Roughgarden isn't suggesting an overhaul of Darwin's theory of sexual selection - she is proposing demolition and redevelopment. Her explanation is that Darwin was wrong to regard sex as solely a matter of reproduction.
It also has a social role. Thus homosexual behaviour, she says, is a way of building same-sex relationships and strengthening the position of an individual within a group. Far from being an anomaly, she says it is widespread and useful.
Indeed, her argument is that many of the traits that Darwin viewed as being used to attract members of the opposite sex - peacock tails, for example - actually play a larger role in same- sex relationships. "Darwin says that certain traits are preferred by females, but in fact there is very little evidence for this.
Plus, Darwin failed to take into account the significance of these traits for other males." Against this background, homosexuality emerges as just one of the traits used in same-sex negotiations.
It is an interesting hypothesis, but challenging even to someone who gave up on the study of biology at the age of 16. My layperson's response is twofold. First, surely reproduction is still the ultimate objective of all organisms?
Doesn't homosexual behaviour get in the way? Second, thinking about the homophobia stirred up by the debate over gay marriage, homosexuality in human society looks like more of a hindrance than a help in same-sex hierarchies. What wider purpose could it serve?
Roughgarden's response is swift, honed by a hundred seminars. There is no conclusive evidence, she says, to support the notion that individuals that exhibit homosexual behaviour produce fewer offspring.
As for human societies, she cites Greek and Roman literature that suggests homosexuality among men was especially prevalent in times of war.
It is possible, she speculates, that it has its roots in the need to form deep relationships of mutual protection. Survival is the first priority of any organism hoping to reproduce - homo sapiens included. (Roughgarden herself has a son.)
We adjourn to the service counter to select a dessert. Then it is back to our table, and back to the peacock's tail, one of Darwin's favourite examples. If the feathery display is for the benefit of other males, on what basis does a peahen select a mate? Personality? Job prospects?
"The biggest problem for Darwin is the failure of experiments to produce evidence of female choice in the way that he viewed it," she explains. When females choose males they seem indifferent to the genes or traits that the male has. They seem more concerned with the power that males might have over the survival and safety of the young. It is his circumstances that are important."
I wonder aloud whether this could be just another area in which we find diversity - some species select mates on the basis of genetic traits, others on the basis of circumstance, and still others on some combination of both.
Roughgarden ponders this for a few seconds before breaking into a wide smile: "I guess it could turn out that Darwin is right on some species and wrong on others. But as a debating position at the moment I am claiming that Darwin is wrong on all of them and I am right on all of them." It is a bold claim - and she knows it.
"If you talk about gender and sexuality the conversation always gets very complex and political. If you talk about animals, people ask about humans. If you talk about humans, people ask about testosterone.
Once you start talking about whether homosexuality is adaptive or not, and whether there is a gene for it or not, you get into the idea that biotechnology could get rid of homosexuality by eliminating the gene. As a society we like to pathologise diversity. That is very dangerous."
Simon London is the FT's US management editor. "Evolution's Rainbow" is published by University of California Press.
The Delancey Street Cafe
San Francisco
1 x Caribbean chicken salad
1 x spicy meatloaf sandwich with salad
1 x lemon poppyseed cake
1 x ice cream sundae
2 x lemonade
2 x coffee
Total: $30
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Copyright © Financial Times group | |