Stephen Jay Gould
Stephen Jay Gould, who recently died of cancer, was an
outstanding contributor to evolutionary theory. But more than this, he had the
rare ability to popularise a wide range of scientific thought. PETE MASON
writes.
GOULD’S SUBJECTS WERE diverse: evolutionary theory,
geology, biological determinism and the history of science. He campaigned
against creationism and racism in scientific research. Describing himself as a
‘leftist’, he "could be seen at demonstrations and on picket lines,
especially during the 1960s and 70s". (Stephen Rose, Guardian, 22 May) In
the same newspaper, Steve Jones compared him to Darwin, "a working
scientist", passing many uncomfortable summers "scraping away at lumps
of rock". Gould’s many books, and particularly his collections of essays,
hit the best-sellers lists, earning him book-jacket acclamations, such as ‘The
greatest living scientist – The Sunday Times’. The US Congress named him one
of America’s ‘living legends’.
Yet to many scientists Gould was a misguided heretic.
Occasionally demonised as a Marxist by his opponents, Gould’s theory of ‘Punctuated
Equilibrium’ (written with Niles Eldredge) moved from a ‘Marxist’
curiosity to a mainstream contender for a more accurate understanding of the
development of species in the thirty years since its publication in 1972.
Gould appears to have consciously attempted to apply a
broadly-Marxist method of analysis to evolution (and the many other subjects he
specialised in). And that’s enough to put most establishment scholars into a
state of fear and loathing.
Gould’s essays, particularly his earlier ones, should be
recommended reading, lessons not just in evolution in nature, but in dialectical
thought. Gould wrote: "Dialectical thinking should be taken more seriously
by Western scholars, not discarded because some nations of the second world [the
so-called Communist East] have constructed a cardboard version as an official
doctrine". (An Urchin in the Storm, 1988, p153) From a left-wing background
(his father was a political activist), Gould concludes this essay with Karl Marx’s
famous remark: ‘Philosophers thus far have only interpreted the world in
various ways: the point, however, is to change it’.
In An Urchin in the Storm, a collection of book reviews
published in the New York Review of Books, Gould writes: "Hegelians and
Marxists have long advocated the ‘transformation of quantity into quality’
as a basic statement about the nature of change. Graded inputs need not simply
yield graded outputs. Instead, systems often resist change and absorb stresses
to a breaking point, beyond which an additional small input may trigger a
profound change of state… Our metaphor about straws and camels’ backs
reflects an implicit understanding that not all change is continuous".
(p209)
Gould applied this particular aspect of dialectical thinking
to the evolution of species in the theory of Punctuated Equilibrium. He points
out that the great evolutionist Ernst Mayr popularised the generally held ‘allopatric
theory’ of speciation, in which small populations of a species become isolated
and undergo very rapid evolution into a new species. Gould points out that all
he has done is recognise that "If evolution almost always occurs by rapid
speciation in small, peripheral isolates – rather than by slow change in large
central populations – then… during [a large central population’s] recorded
history in the fossil record, we should expect no major change". (Ever
Since Darwin, 1978)
Progress & complexity
GOULD ARGUED AGAINST those who suggest that evolutionary
development is driven by a purpose – that there is a guiding hand, as it were,
in evolutionary development – an inevitable progress up a ‘ladder’ from
lower to higher life forms and, finally, to homo sapiens. Natural selection
itself does not imply a progression from lower to higher life forms, argues
Gould: "Life is a ramifying bush with millions of branches, not a ladder.
Darwinism is a theory of local adaptation to changing environments, not a tale
of inevitable progress. ‘After long reflection’, Darwin wrote, ‘I cannot
avoid the conviction that no innate tendency to progressive development exists’."
(An Urchin in the Storm, p211)
One of Gould’s recurrent themes was life’s ‘contingency’.
He does not deny that natural selection leads to a greater complexity of life
forms. But the developing complexity of life, Gould maintains, is only a
by-product ‘incidental’ to evolution and not necessary or inevitable. And
complex creatures represent only a tiny proportion of the whole.
Moreover, evolution on Earth has been punctuated by five
mass extinction events. What role do these events play in shaping evolutionary
development? In Wonderful Life, Gould studies fossils in the Burgess Shale in
the western Canadian Rockies from the Cambrian geological period, half a billion
years ago. These are the remains of the first explosive development of
multi-cellular life. This ‘Cambrian explosion’ is an example of the rapid
development of life forms. But it was followed by the mass extinction of all but
a few of the many weird and wonderful designs.
Gould explains that just a few body forms survived the
aftermath of the Cambrian explosion. Subsequent evolution of these forms
remained confined to the basic architectural design of the original. Gould
argues that if backboned creatures (chordates) had not survived this period,
vertebrates, such as fish and mammals, would never have subsequently evolved.
In Wonderful Life Gould shows how Conway Morris and Harry
Wittington, who studied the Burgess Shale, eventually drew the conclusion that
chance alone governed which of the creatures from the Cambrian explosion
survived the subsequent extinction. Morris, in a major article in Science magazine,
concludes that the "macro evolutionary patterns that set the seal on
Phanerozoic life are contingent on random extinction". (October 1989) If
you were to replay the tape, says Gould in Wonderful Life, and a mass extinction
event expunges the Lungfish group of fish species that crawled onto land out of
the sea, "our lands become the unchallenged domain of insects and
flowers". (p318)
But the anthropologist Richard Leakey, like many
evolutionary biologists, questions Gould’s conclusions. Perhaps some creatures
survived mass extinction events because they were the fittest, while others
survived due to chance. "I believe that Gould has been correct to raise our
consciousness to the role of contingency in life’s flow, although I suspect he
pushes the argument too far". (The Sixth Extinction, p86)
Does complexity not sometimes confer an advantage of
survival even in mass extinction events? If, for instance, the ancestors of the
mammals survived the extinction event that ended the rule of the dinosaurs
because they made their nests in burrows and were able to hibernate through the
devastation of the asteroid impact, would not this be an example of a more
complex set of behaviours leading to survival? On the other hand, maybe the
earliest known ancestor of the vertebrates, Pikaia gracilens, a two-inch
ribbon-like chordate, survived because its backbone was a simpler solution to
body design. Furthermore, what is the role of convergent evolution? Examples of
convergent evolution can be found in the many mammals that returned to the sea
and evolved outwardly to look similar to big fish.
But if this can and did happen, why should Gould appear to
rule out some other sea creature evolving to breathe air and walk on land if the
lungfish didn’t make it? To be sure, close inspection would then reveal a
radically different physiognomy, but convergent evolution and architectural
constraints (another theme of Gould’s) would limit the forms of those land
creatures with larger body sizes.
One of Gould’s most famous collections is The Panda’s
Thumb, in which he describes the evolution of the Panda’s ‘thumb’, a
muscled and flexible digit which evolved from a bony part of its forepaw and is
used to grasp the bamboo the Panda subsists on. Gould concludes with Charles Darwin’s
remark that nature displays a "prodigality of resources for gaining the
very same end" with limited raw material (in this instance Darwin is
referring to orchids). Surely this stands in contradiction to Gould’s claims
that if the lungfish group of species had not survived a mass extinction event,
land would be the ‘unchallenged domain of insects and flowers’. Would not
nature have risen to that challenge?
From Darwin to Dawkins
AMONGST MANY OTHER themes in Gould’s writings (which are
not possible to touch on here) his mastery of the history of science is a joy to
read. In depicting the development of Darwin’s ideas, Gould does not hold back
from demonstrating in fine detail the conflicts within his writings:
"Marx and Engels were quick to recognise what Darwin
had accomplished and to exploit its radical content", remarks Gould (Ever
Since Darwin, 1978) adding that "Darwin was, indeed, a gentle
revolutionary". But Gould also distils out the more conservative elements
in Darwin’s work and presents them for criticism. Darwin was an
"intellectual radical" but a "cultural conservative".
The result was, in turn, a rejection and then an adoption of
the bourgeois ideology (expostulated by the philosopher Edmund Burke 50 years
earlier) of a slow ‘organic’ progress, consciously adopted by the British
ruling class after the French Revolution of 1789 executed a very rapid,
revolutionary type of change in a thorough exposition of the dialectic.
Of course, speciation may still take hundreds, thousands,
and indeed hundreds of thousands of years. But this is still "a geological
microsecond" in the average five million year lifespan of a single species.
By comparison, Gould’s would-be nemesis, Richard Dawkins, author of The
Selfish Gene, writes that evolutionary problems can be solved "if only a
slow, gradual step-by-step pathway can be found". (Climbing Mount
Improbable, 1996)
Dawkins’ Climbing Mount Improbable is clearly meant as a
refutation of Gould and contains a strongly worded denunciation of him. But it
misrepresents the full lifespan of a species, let alone the large-scale
evolution over the history of the planet. Gould, for his part, takes issue with
the reductionism of Dawkins: the fatal flaw of the selfish gene theory is that,
"Selection simply cannot see genes and pick them directly. It must use
bodies as an intermediary. A gene is a bit of DNA hidden within a cell.
Selection views bodies. It favours some bodies because they are stronger, better
insulated, earlier in their sexual maturation, fiercer in combat, or more
beautiful to behold… There is no gene ‘for’ such unambiguous bits of
morphology… bodies cannot be atomised into parts, each constructed by an
individual gene". (The Panda’s Thumb, p76)
Gould protests that Dawkins’s theory arises from
"some bad habits of Western scientific thought… the idea that wholes
should be understood by decomposition into ‘basic’ units; that properties of
microscopic units can generate and explain the behaviour of macroscopic
results".
Gould’s exploration of the complexity of evolutionary
development (and of many other natural processes) is far richer than Dawkins.
Indeed, the lack of a true dialectical, many-sided approach to development,
whether in the natural world or in human society, hinders the development of our
understanding of processes throughout nature and human society, as Gould
demonstrates with great gusto.
By a strange coincidence, a few days before Gould died the
BBC showed an episode of The Simpsons in which Gould was the special guest,
doing a voice-over of a remarkable likeness of himself. Gould would have been
very happy with this as his obituary. His references to popular culture
(particularly baseball) are a defining mark of his essays, which appeared every
month in Natural History magazine for nearly thirty years.
In The Simpsons episode, a giant supermarket chain plants a
fake ‘angel’ fossil, as a marketing ploy. Capitalism is shown using
creationism and exploiting people’s religious beliefs to make a quick buck,
just as the Republican religious right use campaigns around creationism to
bolster support for their anti-working class policies. Gould continually
campaigned against creationism, but never attempted to compromise on a complex
truth when presenting his arguments to the public.
Stephen Jay Gould died on 20 May 2002.
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