In a recent post, I discuss how my dislike of a scientist complicates my judgment of his or her work. I call this complication “the Gould effect,” because it came into play when I interviewed Stephen Jay Gould in 1995. I profiled Gould, who died in 2002, in Scientific American in 1995 and at greater length in my book The End of Science, which was re-published this year. Below is an edited version of the latter profile, titled “Gould’s Contingency Plan.” – John Horgan

No field of science is as burdened by its past as evolutionary biology. It reeks of what literary critic Harold Bloom called the anxiety of influence. In fact, the discipline of evolutionary biology can be defined to a large degree as the ongoing attempt of Darwin's intellectual descendants to come to terms with his overwhelming influence.

Naturally, some modern biologists bridle at the notion that they are merely adding footnotes to Darwin's magnum opus. One of the most celebrated rebels of evolutionary biology is paleontologist Stephen Jay Gould. He has sought to resist the influence of Darwin by denigrating natural selection’s power, by arguing that it doesn't explain that much. Gould began staking out his philosophical position in the 1960's by attacking the venerable doctrine of uniformitarianism, which held that the geophysical forces shaping the earth and life have been more or less constant through its history.

In 1972 Gould and Niles Eldredge extended this critique of uniformitarianism to biological evolution by introducing punctuated equilibrium (also called “punk eek” or “evolution by jerks”). New species were only rarely created through the gradual, linear evolution that Darwin described, Gould and Eldredge argued. Rather, speciation is a relatively rapid "event" that occurs when a group of organisms veers away from its stable parent population and embarks on its own genetic course. Speciation must depend not on the kind of adaptive processes described by Darwin but on much more particular, complex, "contingent" factors.

In subsequent writings, Gould hammered away relentlessly at ideas that he claims are implicit in many interpretations of Darwinian theory: progress and inevitability. Evolution does not demonstrate any coherent direction, Gould asserts, nor are any of its products--such as Homo sapiens--in any sense inevitable; replay the "tape of life" a million times and this peculiar simian with the over-sized brain might never re-emerge. He has also attacked genetic determinism, whether in pseudo-scientific claims about race and intelligence or much more respectable theories related to sociobiology.

Gould packages his skepticism in a prose rich with references to culture high and low and suffused with an acute awareness of its own existence as a cultural artifact. He has been stunningly successful; almost all his books have been bestsellers, and he himself is one of the most widely quoted scientists in the world.

Before meeting Gould, I was curious about several seemingly contradictory aspects of his thought. I wondered just how deep his skepticism and aversion to progress ran. Did he believe, with philosopher Thomas Kuhn, that science itself does not demonstrate any coherent progress? Moreover, some critics--and Gould's success ensured that he had legions--accused him of being a crypto-Marxist. But Marx’s highly deterministic, progressive view of history seemed antithetical to Gould's.

I also wondered whether Gould was backing away from punctuated equilibrium. In the headline of their original 1972 paper, Gould and Eldredge boldly called punk-eek an "alternative" to Darwin's gradualism that might someday supersede it. In a retrospective essay published in Nature in 1993, "Punctuated equilibrium comes of age," Gould and Eldredge suggested that their hypothesis might be "a useful extension" or "complement" to Darwin's basic model. Punk meek.

Gould and Eldredge concluded the 1993 essay with a spasm of disarming honesty. They noted that their theory was only one of many modern scientific ideas emphasizing randomness and discontinuity rather than order and progress. "Punctuated equilibrium, seen in this light, is only paleontology's contribution to a Zeitgeist, and Zeitgeists, as (literally) transient ghosts of time, should never be trusted. Thus, in developing punctuated equilibrium, we have either been toadies and panderers to fashion, and therefore destined to history's ash heap, or we had a spark of insight about nature's constitution. Only the punctuated and unpredictable future will tell."

I suspected that this uncharacteristic modesty could be traced back to the 1970s, when creationists seized on punk eek as "proof" that the theory of evolution was not universally accepted. Some biologists blamed Gould and Eldredge for having encouraged creationists with their rhetoric. Gould tried to set the record straight by testifying at an Arkansas trial held to determine whether creationism should be taught in schools. Gould was forced to admit, in effect, that punctuated equilibrium was a rather minor technical matter, a squabble among experts.

Gould is disarmingly ordinary-looking. He is short and plump; his face, too, is chubby, adorned with a button nose and greying Charley Chaplin moustache. When I met him, he was wearing wrinkled khaki pants and an Oxford shirt; he looked like the archetypal rumpled, absent-minded professor. But the illusion of ordinariness vanished as soon as Gould opened his mouth. When discussing scientific issues, he talked in a rapid-fire murmur, laying out even the most complex, technical argument with an ease that hinted at much vaster knowledge held in reserve. He sprinkled his speech, like his writings, with quotations, which he invariably prefaced by saying, "Of course you know the famous remark of..."

As he spoke, he often appeared distracted, as if not paying attention to his own words. I had the impression that mere speech was not enough to engage him fully; the higher-level programs of his mind roamed ahead, conducting reconnaissance, trying to anticipate possible objections to his discourse, searching for new lines of argument, analogies, quotations. No matter where I was, Gould seemed to be way ahead of me.

Gould acknowledged that his approach to evolutionary biology had been inspired in part by Kuhn's Structure of Scientific Revolutions, which he read shortly after it was published in 1962. The book helped Gould believe that he, a young man from "a lower-middle-class family in Queens where nobody had gone to college," might be able to make an important contribution to science. It also led Gould to reject the "inductivist, ameliorative, progressive, add-a-fact-at-a-time-don't-theorize-'til-you're-old model of doing science."

I asked Gould if he believed, as Kuhn did, that science did not advance toward the truth. Shaking his head adamantly, Gould denied that Kuhn held such a position. "I know him, obviously," Gould said. While Kuhn was the "intellectual father" of the postmodernists, he nonetheless believed that "there's an objective world out there.” Although this objective world is in some sense very hard to define, "we have a better sense of what it is now than we did centuries ago."

So Gould, who had striven so ceaselessly to banish the notion of progress from evolutionary biology, was a believer in scientific progress? "Oh sure," he said mildly. "I think all scientists are." No real scientist could possibly be a true postmodern skeptic, Gould elaborated, because “the day-to-day work of science is intensely boring. You've got to clean the mouse cages and titrate your solutions. And you’ve got to clean your petri dishes." No scientist could endure such tedium unless he or she thought it would lead to "greater empirical adequacy."

Gould glided just as easily past my queries on Marx. He acknowledged that he found some of Marx's ideas quite attractive. Marx's claim that ideas are socially embedded and evolve through the clash of theses and antitheses "is actually a very sensible and interesting theory of change," Gould remarked. Marx's view of social change, in which "you accumulate small insults to the system until the system itself breaks," is also quite compatible with punctuated equilibrium.

I hardly had to ask the next question: Is Gould, or was he ever, a Marxist? "You just remember what Marx said," Gould replied before my mouth closed. Marx himself, Gould "reminded" me, once denied that he was a Marxist, because Marxism had become too many things to too many people. No intellectual, Gould explained, wants to identify himself too closely with any "ism," especially one so capacious.

Gould also disliked Marx's ideas about progress. "Marx really got caught up in notions of pre-destiny and determinism, particularly in theories of history, which I think ought to be completely contingent. I really think he's dead wrong on that."

On the other hand, Gould did not rule out the possibility that culture could progress. "Because social inheritance is Lamarckian, there is more of a theoretical basis for belief in progress in culture. It gets derailed all the time by war, et cetera, and therefore it becomes contingent. But at least because anything we invent is passed directly to an offspring, there is that possibility of directional accumulation."

When I asked Gould about punctuated equilibrium, he defended it in spirited fashion. The real significance of the idea, he said, is that "you can't explain [speciation] at the level of the adaptive struggle of the individuals in Darwinian, conventional Darwinian, terms." The trends could only be accounted for by mechanisms operating at the level of species.

"You get trends because some species speciate more often, because some species live longer than others," he said. "Since the causes of the birth and death of species are quite different from the causes of the birth and death of organisms, it is a different kind of theory. That's what's interesting. That's where the new theory was in punk eek."

When I asked Gould why he switched from calling punk eek an "alternative" to Darwinism in 1972 to "complement" in 1993, he insisted that he wasn’t downplaying the theory. “Gradualism had pretty complete hegemony” before he and Eldredge challenged it in 1972, he said. “I think punctuated equilibrium has an overwhelmingly dominant frequency in the fossil record, which means gradualism exists but it's not really important in the overall pattern of things."

As Gould continued speaking, however, I began to doubt whether he was really interested in resolving debates over punctuated equilibrium or other biological issues. When I asked him if he believed biology could achieve a final theory—analogous to the final theory sought by physicists--he grimaced. Biologists who believe in a final theory are "naive inductivists," he said. "They actually think that once we sequence the human genome, well, we'll have it!"

Even some paleontologists, he admitted, probably think "if we keep at it long enough we really will know the basic features of the history of life and then we'll have it." Gould disagreed. Darwin "had the answer right about the basic interrelationships of organisms, but to me that's only a beginning. It's not over; it's started."

So what did Gould consider to be the outstanding issues for evolutionary biology? "Oh, there are so many I don't know where to start." Theorists still had to determine the "full panoply of causes" underlying evolution, from molecules on up to large populations of organisms. Then there are "all these contingencies," such as the asteroid impacts that are thought to cause mass extinctions. "So I would say causes, strengths of causes, levels of causes and contingency."

Gould mused a moment. "That's not a bad formulation," he said, taking a notebook from his shirt pocket and scribbling in it.

Then Gould cheerfully rattled off all the reasons why science would never answer all these questions. As an historical science, evolutionary biology can offer only retrospective explanations and not predictions, and sometimes it can offer nothing at all because it lacks sufficient evidence. "If you're missing the evidence of antecedent sequences, then you can't do it at all," he said. "That's why I think we'll never know the origins of language. Because it's not a question of theory; it's a question of contingent history."

Gould suggested that the human brain, designed for survival in pre-industrial society, is simply not capable of solving certain problems. Research has shown that humans are inept at dealing with probabilities and the interactions of complex variables--such as nature and nurture. "People do not understand that if both genes and culture interact--of course they do--you can't then say it's 20 percent genes and 80 percent environment. You can't do that. It's not meaningful. The emergent property is the emergent property and that's all you can ever say about it."

The mind might also resist scientific reduction, although not because it possesses mystical qualities. "I'm an old-fashioned materialist," Gould said. "I think the mind arises from the complexities of neural organization, which we don't really understand very well."

Given all these limits, is it possible that biology, and even science as a whole, might simply go as far as it can and then come to an end? Gould shook his head. "People thought science was ending in 1900, and since then we've got plate tectonics, the genetic basis for life. Why should it stop?"

And anyway, Gould added, our theories might reflect not reality but our own limitations as truth-seekers. Before I could respond, Gould had already leaped ahead of me. "Of course, if those limits are intrinsic, then science will be complete within the limits. Yeah, yeah. Okay, that's a fair argument. I don't think it's right, but I can understand the structure of it."

Gould's great bugaboo is lack of originality. After all, Darwin himself anticipated punctuated equilibrium in On the Origin of Species: "Many species once formed never undergo any further change... and the periods, during which species have undergone further modification, though long as measured by years, have probably been short in comparison with the periods during which they retain the same form."

The key to understanding Gould may be not his alleged Marxism, anti-authoritarianism or postmodernism but his fear that he might not have anything important to contribute to modern biology. Gould noted during our interview that many scientists do not consider history—which resists reduction to general principles, such as evolution by natural selection--to be a science. "I think that's a false taxonomy. History is a different type of science." Gould found the fuzziness and contingency of history exhilarating. "I love it! That's because I'm an historian at heart."

By transforming evolutionary biology into history--an intrinsically subjective, interpretive discipline, like literary criticism--Gould makes it uniquely suited for someone with his vast rhetorical skills. If the history of life is a bottomless quarry of largely random events, he can keep mining it, verbally cherishing one odd fact after another, without ever fearing that his efforts have become trivial or redundant.

Whereas most scientists seek to discern the signal underlying nature, Gould keeps drawing attention to the noise. After all, punctuated equilibrium is not really a theory; it is a description of noise. Gould’s view of life can be summed up by the old bumper-sticker slogan: Shit happens.

Further Reading:

The Gould Effect: When a Science Journalist Dislikes a Scientist.

What Thomas Kuhn Really Thought about Scientific "Truth."

A Profile of Biologist, Warrior, Poet, Philosopher Edward O. Wilson.

The End of Science (2015 edition).

Was I Wrong about The End of Science?