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Stephen Jay Gould

America's premier science writer talks about the battles over evolution, the importance of dinosaur lunch boxes, and why no one's likely to top Ty Cobb's batting average.

Q: Of all your work, what has stirred up the most controversy?

A: The material on evolutionary theory, because you have a very committed group of strict Darwinian thinkers among technical scientific audiences. And although Darwin's my hero and his theory is a good one, a lot of the work I've done is meant to question strictly Darwinian notions. Darwin's principle of natural selection leads to the prediction that the proper way to analyze any evolutionary trend or evolutionary development is to see the new features as adaptive to environments. And that's a perfectly good principle. The problem is that there are many evolutionary biologists who view everything that happens in evolution -- every feature, every behavior -- as directly evolved for adaptive benefit. And that just doesn't work. Whenever you build a structure for adaptive reasons, the structure is going to exhibit properties that have nothing to do with adaptation. They're just side consequences.

Q: Could you give an example?

A: I'll give you the obvious one: Let's say the human brain gets big for natural selection reasons. Let's say it's an adaptation. There are some things we needed to do on the savannas of Africa for which a big brain was good. Now that doesn't imply that everything the big brain can do is therefore an adaptation. But that's the error that many so-called evolutionary psychologists make. Our brains didn't get big so that we could write, so that we could read, so that we could compose operas, so that we would know the facts of our personal mortality -- those arise as side consequences of building a big brain for other reasons. Not to mention random things that occur in evolution. We wouldn't be here if the impact of a large extraterrestrial body hadn't removed the dinosaurs. That wasn't adaptation or natural selection. That was just a bad break. Mammals happened to survive because they were tiny little creatures that could hide -- because they never had any evolutionary success competing with dinosaurs. And so it's lucky that we're even here.

Q: You take issue with the tendency to characterize evolution in terms of trends.

A: People are storytelling creatures. We like stories that go somewhere, and therefore we like trends -- because trends are things that either get better or get worse, so we can either rejoice or lament. The point of my latest book, Full House, is to show that we mistakenly depict many things as trends moving in some direction. We take the "full house" of variation in a system and try to represent it as a single number, when in fact what we should be doing is studying the variation as it expands and contracts. If you look at the history of the variation in all its complexity, then you see there's no trend.

Q: For example?

A: Well, when we think about evolution, we have a tendency to focus on the most complex creature at any given time. Once the most complex creature was a bacterium, then it was a jellyfish, then a trilobite, then a fish, and then us. But the history of the most complex creature is not a surrogate for the general thrust of evolution as a whole. At the origin of life you had to have creatures of minimal complexity because, given the nature of chemistry and physics, you can't precipitate a hippopotamus out of the primordial soup. So, you're going to begin with a creature of bacterial grade, the simplest kind of cellular organization. And there's only one direction for change -- toward more complexity. But very few creatures move in that direction. Occasionally a couple of species dribble off in the direction of complexity, but that doesn't define a trend or a thrust. The most outstanding feature of life's history is that through 3.5 billion years this has remained, really, a bacterial planet. Most creatures are what they've always been: They're bacteria and they rule the world. And we need to be nice to them.

Q: Nice to bacteria?

A: Right. I don't think this leads us to any startling new ideas about how we can keep going, but if I can impart some increased respect for those creatures that we consider simple and inferior, then I'll have done a good deed.

Q: In your book you examine the inability of baseball players to hit .400 anymore and argue that it's because hitting has improved.

A: The overall batting average has been about .260 throughout the history of baseball. But the variation around that average has shrunk. It's at least plausible that variation declines because play improves. A batting average is a comparison between hitting and pitching. So if everybody's improving, as long as they improve at the same rate, the batting average will remain constant. But it gets to the point where everyone is so good that there's just not much variation anymore. Hitting .400 in baseball is a good example because there's a "right wall," if you will, of human limits. Given how our muscles work, there's just so much that the human body can do. There will always be a few individuals who, by dint of genetic gifts and obsessive commitment and training, will stand close to that right wall. That's where Ty Cobb was in 1911 and where Tony Gwynn is today. But there is this limiting wall. What has happened in baseball is that all aspects of play have improved enormously. Back in 1911, average play was so far inferior to where Ty Cobb was that his batting average could be measured as .420. Today, Tony Gwynn is just as good, maybe even closer to the wall than Cobb was. But the average player has improved so much that Gwynn's performance -- equal to or better than Cobb's -- is not measured as high.

Q: In Full House you also use your bout with cancer to explain your theory about statistical fallacies. Why did your doctor initially withhold information from you?

A: I think she was being compassionate. You see, the form of cancer I had -- abdominal mesothelioma -- was said to be incurable at the time. Luckily, I got it when they figured out some techniques that turned out to work pretty well. But my doctor didn't know me, and I think she rightly feared that if I got the standard articles about my cancer and read "median mortality: eight months," I would misinterpret that in the usual way people do, namely: I'll probably be dead in eight months. But luckily I had statistical training, and I didn't read it that way. A measure of central tendency -- a mean, a median, or a mode -- is not a prediction about me. It's just a measure that summarizes the variation of the whole. I said, look, if the median mortality is eight months, meaning that half the people die within eight months of diagnosis, where am I going to fit? Am I likely to be in the upper half or the lower half? What is the curve like for the half that lives longer? Maybe it has an extended right tail that goes on for many years. I decided that I was likely to be on that right tail.

Q: What are your thoughts on the controversy surrounding current scientific funding? Do you agree that it is too politicized?

A: How did scientists get money in the past? They were either lucky and independently wealthy, like Darwin, or they had patrons, like Galileo. Universities or governments have become patrons only in the last few generations. Many of the great scientists of the past were in debt to their patrons in the same sense that modern scientists are influenced by what their granting agencies want.

Q: Do you think science is becoming more accessible to the public?

A: Oh, no doubt about it. When I was interested in dinosaurs as a kid in New York in the '40s, what was there to sustain my interest? There were no films or lunch boxes or pencils emblazoned with dinosaurs. If you were interested in dinosaurs, you were seen as a nerd on the school playground. Just as the British are fond of saying that wars are won or lost on the playing fields of Eton, I think many scientific careers are squelched on the playgrounds of Shady Oaks Elementary. There are always some really committed people, like me as a kid, who take the teasing, but many people who would have been very good scientists were just permanently derailed.

Q: Your childhood nickname was "fossil face." Did you put up with a lot as a kid?

A: No more than New York kids inevitably put up with. The only time I ever got beat up was when I admitted to being a Yankee fan in Brooklyn. That was kind of dumb.

Q: How do you get children to form an interest in science?

A: I think it's there already. That's why I take heart. It's true that the level of scientific knowledge among adults is very low, but that's not because there isn't a natural interest. I think most kids are fascinated by the natural world. I've often said that if you could quantify the mental power involved in all the dinosaur names correctly known and correctly spelled by 5-year-old kids in America, you could move any mountain on earth.

Q: What do you suppose accounts for children's obsession with dinosaurs?

A: I once asked Sheldon White, the child psychologist, and I loved his answer: "Big, fierce, and extinct."

Q: What ultimate effect would you like your work to have?

A: I hope it will be one further step in the kind of humility that would benefit humans enormously with regard to our powers and possibilities on this planet. I think we want to be around for a while. We'd better understand that we weren't meant to be, and we don't have dominion over everything, and we're not always as smart as we think.

Michael Krasny is a professor of English at San Francisco State University and the host of the KQED-FM "Forum" radio show, where portions of this interview were aired.

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