Sunday, September 1, 1996

Q&A Stephen Jay Gould: Basically Bacteria



We are glorious accidents of an unpredictable process with no drive to complexity, not the expected results of evolutionary principles that yearn to produce a creature capable of understanding the mode of its own necessary construction.
     Full House: The Spread of Excellence From Plato to Darwin

HB:  Full House  can be described is a book about the nature of narrative.

SJG: That’s fair.

HB:  I had never thought before about statistics or trends as narratives in disguise. I’ve always thought of information as inherently anti-narrative.

SJG: Certain kinds of information are. I don’t think trends are.

HB:  You say that trends speak to our story-telling, story-loving nature.

SJG: In an earlier book, Time's Arrow, Time's Cycle: Myth and Metaphor in the Discovery of Geological Time, I wrote about different views of time. The point, not original with me, is that of those two great models of time, circular and linear, the circular may be a very old and pervasive way of looking at time but it doesn’t lend itself to the kind of stories that the Western tradition likes, which are directional stories, time’s arrow stories.

Trends are bare-bones stories — things moving somewhere.
HB:  You say we look at trends in such a way that we can’t help but see the story of human evolution as predetermined, triumphal.

SJG: Meant to be, giving us dominion. I suspect the reason for the interest in trends is that what we’re really interested in validating our own specialness above anything else. We like lamentation trends, like the trend away from .400 hitting, because it enables us to think that once we were better, so what we don’t like about ourselves we can attribute to decline. The hero triumphs, then falls; that’s part of the saga, too.

HB:  So can talk about the good old days of baseball.

SJG: We love good old day stories. The ultimate good old day story is the Renaissance belief that you couldn’t get beyond classical Greece and Rome. All you could have is a renaissance of what had been great.

HB:  You point out that Darwin himself was divided on the issue of progress in evolution. On the one hand, he asserted there was only variation, not progress. On the other hand, belief in progress was so pervasive in the culture he had to accommodate to it.

SJG: There were many Darwins, as there are many of all of us. He was a philosophical revolutionary, a political liberal, and a social conservative, that is, a lifestyle conservative, a wealthy man who loved genteel living in the countryside. But as a philosophical radical, he loved to play with ideas. He was delighted with the notion that natural selection as a bare-bones theory did not imply progress. He thought that was fabulously interesting compared to most prejudicial views of the subject. On the other hand, as an eminent Victorian living in a society more committed, perhaps, than any other in human history to the notion of progress he was never able to break away completely.

HB:  If he had been able to take a principled stand against the notion of evolutionary progress, it would have been much harder for social Darwinism in all its racist forms to graft itself on to him.

SJG: That’s a fair statement. It’s fair, on the one hand, to say that social Darwinism is a misnomer, that you can’t really draw these implications out of natural selection theory. On the other hand, it’s not true that he actively rejected it. He was kind of interested. He was leery about some of the broader implications but he was intrigued. Darwin was too genial a man to want to see it used for the suppression of people, though, politically, he had fairly conventional views about the ranking of people.

HB:  Through Social Darwinism, Darwinism reinforced racism by providing a pseudo-scientific context for it. It gave racism new strength; modernized it.

SJG: I wouldn’t want to call it Darwinism. Once you make a transition to evolutionary theory, any kind of evolutionary theory . . .

HB:  But the effect of Darwinism was to say now you’ve got science with you.

SJG: That was going to happen Darwin or no Darwin.

HB:  Though Wallace took another view.

SJG: Oh, yeah, but for many other reasons. You wouldn’t want his spiritualism, his exceptionalism, and although he was close to egalitarian in his views about human capacities, he had fairly standard chauvinist views about human achievements. He thought that savage societies were pretty savage. True, the savage brain was as good as ours. That was the crux of his argument against the natural selection of the human brain. The savage brain is as good as ours but they don’t use it. If they don’t use it, he argues, how then can natural selection have made it?

HB:  That argument is perennial: the human brain is too big, too powerful, to have evolved in response to any requirement natural selection imposed on it. It must be here for another reason.

SJG: Another kind of exceptionalism. A lot of people are fond of saying that the human brain presents one of the biggest evolutionary enigmas because it’s the result fastest rate of evolutionary change we know. I’d love to trace the origin of that. It’s nonsense. The step from the Homo erectus brain to Homo sapiens is fairly rapid but compared to the data we have on the lengthening of ovipositors in wasps, say, it’s not all that extraordinary.

HB:  Your theory of punctuated equilibrium maintains that just this sort of thing — big leaps, fast evolutionary changes — are the rule.  According to punctuated equilibrium, mostly nothing happens at all. But when it does happens, it’s fast.

SJG: People understand that the human body hasn’t changed much in 10,000 years and they see that as paradoxical, since they think evolution means constant change. They know  humans have culture, of course, so they assume that culture must have suppressed biological evolution. What they don’t understand is that nothing suppressed anything. That kind of stability is exactly what you’d predict. Darwinian evolution is operating in its usual mode in large, successful, world-wide species, that is, it’s keeping the species stable.

HB:  You state repeatedly in Full House that if we could play start the tape of evolution over, there is almost no chance a self-conscious species would arise.

SJG: I wouldn’t think the probability is awfully high. If in the history of life on earth you saw multiple parallel trends in the direction of consciousness, you might say, well, it’s like wings, or eyes, but you don’t. You only see one peculiar lineage of mammals getting anywhere.

HB:  So it’s a freaky outcome.

SJG: It would seem to be since it only happened once in the only experiment we know, whereas eyes evolved fifty times, wings half a dozen.

HB:  It’s important to your argument that evolution has what you call a  left wall; that is, you can’t get simpler than the simplest bacteria. There’s only one way to go. Things can only get more complex.

But it does not seem obvious to me that there is a left wall. Why couldn’t bacteria devolve? Why is complexification the only avenue for change?

SJG: Remember I’m talking about what I call a left wall of minimal preservable complexity in the fossil record. Bacteria is the simplest thing you’re going to have a record of, compared, say, to viruses or prions.

HB:  But you’re still saying  the transition from primal soup to simple life is pretty much inevitable. Why is that inevitable, when the development of any further complexity is not inevitable? Is that purely an intuition of yours?

SJG: I’m not sure it’s only intuitive. If the Martian evidence is right, then there is evidence of a second occurrence of simple life forms. I’m not putting much money on that, although it’s a plausible case.

I’m no expert in research on the origin of life, but I think although no life in a test tube has been made we have so many of the pieces now it just doesn’t seem a big step to make something you want to call living out of primary constituents of original atmosphere and oceans. I don’t mean to understate the complexity but we almost know how it happens, and it doesn’t seem that hard.

When I was first studying the subject the conventional view was that life was wildly improbable, close to miraculous, and that half of the earth’s history was lifeless. And of course that’s not true. Immediately after conditions became appropriate on the earth’s surface, you had life. That doesn’t prove it had to be, I understand that. Still it’s a tempting inference. If it happened as soon as it could, then maybe it had to be.

HB:  After the origin of life, all further developments are subject to contingency. But the origin of life, as you see it, is not contingent.

SJG: It is chemistry.

HB:  You use the example of a drunk leaving a bar. Presumably, the door to that bar closes behind him. He can’t go back in. Sooner or later, then, if he’s staggering around purely at random, he has to wind up in the gutter. You  say that is parallel to the development of complexity.

But what if the bar door is open?

SJG: But it isn’t.

HB:  What about the Martian rock? Isn’t that a case where life may have come and gone?

SJG: A planet can go dry. There’s no guarantee that once life originates it’s got to develop this right tail of complexity. In fact, it may often end. Mars dried up and froze, though there may still be bacteria in the subsurface.

HB:  You’ve always emphasized the effect of society on science and the scientist. In that vein, Arthur Danto described punctuated equilibrium as one version of a pervasive new model of change. In The Philosophical Disenfranchisement of Art, he wrote:
 . . .  whereas theorists used to see continuity, we see discontinuity everywhere. Think of the history of science, as seen by Thomas Kuhn . . . of the archeology of knowledge, as practiced by Foucault . . . Even the theory of evolution today has this structure. Whereas it used to be that when there were discontinuities in the fossil record, scientists would say the record was incomplete, and look for what were called missing links, the new evolutionists say instead that the record is complete: it is evolution that is discontinuous. The theory of punctuational equilibrium represents evolution as sequence of catastrophic flips, as it were, abrupt shifts to a new level after which there is no change to speak of until the next one.

SJG: He exaggerates somewhat; we don’t say the record is complete. But what I like about that paragraph is he makes the same comparisons I do to Foucault. I’ve always seen punctuated equilibrium as paleontology’s manifestation of the zeitgeist. I was strongly influenced by Kuhn and said so in the very first thing we ever wrote on punctuated equilibrium in 1972.

In 1993 when the theory was 21 years old,  a leading professional journal of science asked us to write a retrospective, and I ended by saying I didn’t know whether we were part of the zeitgeist and about to wind up the ash can of history, or had actually found something interesting. Because the social embeddedness of science is not always a negative. Sometimes it helps you along to an insight you didn’t have before. It may come through cultural analog rather than empirical discovery but still be an insight.

Ecco Darwin. It’s well known that Darwin got a lot of the logic of natural selection from Adam Smith’s economics. This is an example of a cultural context being very helpful, though it’s also ironic, because laissez-faire doesn’t really work when it comes to economics but does just fine in biology.
HB: You work with iconography in Full House, and demonstrate its staying power, and its ability to shape our way of thinking.

SJG: Right. I’d looked at images of evolution for forty years without ever questioning them. That was the history of life. It’s such a ridiculously narrow and biased viewpoint, tracing the history of the most complex things only, which is OK, as long as you don’t claim it represents the full history of life.

HB:  Could the iconography, showing, say, horses and Homo sapiens arising triumphantly from extinct species, be a holdover of a pre-Darwinism way of thinking? It seems so much more applicable to the Great Chain of Being, which really is a ladder with ascent, hierarchy, top and bottom

SJG: There is a book on this subject by Martin Rudwick, an historian of geology, called Scenes from Deep Time. He points out the genre starts in the 1850s when you first have a geological time scale, and that ever since there’s been similar iconography. He asks, if this is the beginning of the genre, where did it come from? The connection he makes, and I’m sure he’s right, is to the tradition of the biblical illustration of the days of Genesis — which is indeed the Great Chain of Being — where you have the drawing of a sequential order to life.

HB:  Is Full House aimed at the scientist as well as at the lay person?

SJG: The professional paleontologist knows there were lots of invertebrates, lots of bacteria. But I think the bias still imposes itself on professional life. Many evolutionary biologists still think evolution must somehow, however vaguely, be progressive, and that there’s somehow a tendency to greater complexity.

So it’s meant to say something a little challenging to professionals. It’s meant to tell them, bust out of your own iconographies. You may be able to articulate a correct notion of progressivism but you haven’t really built it into the guts of your work.

HB:  You write about your recourse to statistics during your recovery from cancer. Did you develop your view of statistics as a way of coming to terms with the odds against you, or was it already complete and ready to be applied?

SJG: It’s hard, twelve years later, to remember the actual sequence. I do remember going to the library and getting all the literature on mesothelioma and reading right away — eight months median mortality. I gulped, of course. What else would anyone do? And I do remember saying, wait a minute, that’s a half way point; half of the people with the disease will die within eight months, half will live longer. And I remember thinking, it has to be right-skewed because there isn’t much room between zero and eight months. And then saying, I’m probably going to be in the right half, this isn’t as bad as it sounds.

I think it was only later I said, wait, this is a general issue. But I don’t really know. I was already looking  into .400 hitting, noting there had to be shrinking variation. I did that first calculation when I was ill, sitting in bed. It was something I could do with the Baseball Encyclopedia.

HB:  What has the response been from within the scientific community? Have people been taking issue with you on technical grounds?

SJG: Not really. Some of the complexity theorists in Sante Fe would like to think there’s more to complexity than just a dribbling right tail on a Bell curve. My response to them is that I don’t deny that there may be general principles about the nature of complexity when it happens — but that doesn’t mean there’s a drive toward complexity. They want more. But in general the professional response has been pretty good.

HB:  How do you conceive of yourself as a writer?

SJG: I just love to do it. In that respect I think I am different from most scientists. Most scientists I know, even some who are pretty good at it, view writing as a chore. Doing the work is the joy and writing it up is a necessary burden. For me, the work isn’t a joy until you write it. Writing is the climax. It’s also the one time you can be totally by yourself with your own thoughts — no e-mail, no phone.

HB:  Writing is at the core of the enterprise .

SJG: I do see it at the core whereas most scientists see it as subsidiary. The negative statement would be, he does it for money and for glory. I don’t think that’s right. The positive would be he does it because he has such a burning capacity to communicate his feelings. But that’s not true either.

The truth is that I write those essays for myself. I write essays because there’s a never ending search to write the perfect essay, which is impossible.  I keep doing it because it’s essential. It’s how I learn.

HB:  What sort of science writing do you like?

SJG: I once made a division, a bit simplistic, between two great traditions of science writing. One of them is Galilean,  with a tendency to focus on the fascination of nature’s puzzles. I call it Galilean because Galileo wrote his two great dialogues in Italian and not as formal Latin treatises. Darwin is surely in that tradition. Darwin can wax poetic but the power is mainly in the argument and the fascination of examples. People tend to think The Origin of Species is a popular version of some technical monograph he wrote. They don’t realize he chose to present this great work as a book for the general public, and there is no technical monograph corresponding to it. I see myself in that tradition — trying to write as clearly, elegantly, and broadly as possible about the fascinating intellectual puzzles of nature.

The other tradition, which I call Franciscan, is nature poetry. I respect people who can do that, Loren Eisely, for example. Lewis Thomas is somewhat in between. Edward Wilson is somewhat in between; he can get quite poetic. I can for a paragraph or two every once and a while but it’s not going to be my general style.

HB:  Writing for a broad audience helps implement the agenda of keeping science connected to society.

SJG: I think so. It would probably help my reputation if I let it out that I do it out of a sense of duty as a scientist trying to communicate with the public. I believe in that, but it’s not what primarily motivates me. It really is literary. If it weren’t literary, I would have run out of gas a long time ago. You don’t have to write seven volumes of essays. What keeps me going is internal need. 

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