Strange Case Excerpt

ChAPter 4

The SynTheSiS and handy man

if i hAd tO OPt fOr One single yeAr As the mOst mOmentous in the twentieth-century intellectual history of paleoanthropology, I

would unhesitatingly choose 1950. Theodosius Dobzhansky had, of course,

already put the Synthesis cat among the paleoanthropological pigeons back

in 1944, but it was wartime, and nobody seems to have taken much imme-

diate notice. Nonetheless, Dobzhanskys take on human evolution pointed

to the future, and in many ways the end of World War II, the year after his

article appeared, also marked the passing of the old guard in paleoanthro-

pology. In 1948 the aged though still-industrious Arthur Keith published

a volume entitled A New Theory of Human Evolution, but the book actu-

ally did little to deliver on its title. It is mostly remembered, if at all, for its

vaguely anti-Semitic stance. The time had come for a new cast of characters

to step onto the paleoanthropological stage.

A leader among the new generation of biological anthropologists was

Sherwood Washburn. Rather conventionally trained at Harvard during the

1930s, Washburn enthusiastically embraced the New Evolutionary Syn-

thesis after joining Dobzhansky on the Columbia faculty in 1940. And it

was with this energetic convert that the Synthesis at last acquired a conduit

into paleoanthropology. In 1950 Washburn (by then at the University of

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70 The STrange CaSe of The riCkeTy CoSSaCk

Chicago) and Dobzhansky jointly organized a conference hosted by Long

Islands Cold Spring Harbor Laboratory. Grandly titled The Origin and

Evolution of Man, this international meeting brought together numer-

ous luminaries of paleoanthropology and adjacent sciences, including all

three of the giants of the Synthesis. It was thus loaded with star power, but

in retrospect, one contribution stands out not only as the most newswor-

thy presentation at the conference, but also as one of the most influential

benchmarks ever in paleoanthropology. Significantly, it was not made by a

paleoanthropologist. It was made by the ornithologist Ernst Mayr.

As forceful on the printed page as in oratoryalthough his published

version bears all the marks of haste in preparationMayr didnt bother to

mince his words. In no uncertain terms, he informed the assembled multi-

tude that the picture of complexity in human evolution implied by all those

hominid species and genera was just plain wrong. To begin with, he de-

clared, both the theoretical and the morphological yardsticks by which the

anatomists had differentiated them were entirely inappropriate. For exam-

ple, if you took a couple of fruit fly species and blew them up to human size,

they would look much more different from one another than the members

of any pair of living primate species do. And the same went in spades for

fossil hominids.

Spectacularly irrelevant as the metaphor was, it resonated with an au-

dience that was uncomfortably aware of the thin theoretical ice on which

it skated. And it primed that audience for Mayrs more specific claim, that

the supposed diversity of hominid genera and species just didnt exist. What

was more, Mayr continued, even in principle there was no way in which that

diversity could have existed, because the possession of material culture so

remarkably broadened the ecological niche of tool-wielding hominids that

there would never have been enough ecological space in the world for more

than one human species at a time.

Put together, Mayr said, these various practical and theoretical consid-

erations dictated that every one of the human fossils known should be placed

within a single evolving polytypic lineage. And not only was there a mere

three species recognizable within that lineage, but every one of those spe-

cies belonged to a single genus: Homo. As Mayr saw it, Homo transvaalensis

(the australopiths) had given rise to H. erectus (including Pithecanthropus,

Sinanthropus, and so forth), which in turn evolved into H. sapiens (includ-

ing the Neanderthals). And that was it.


The SynTheSiS and handy man 71

Stillas if he somehow felt that things couldnt have been quite this

simpleMayr inquired explicitly why, unlike virtually any other success-

ful mammal family, Hominidae had not thrown off a whole array of species.

What, he asked, is the cause of this puzzling trait of the hominid stock to

stop speciating in spite of its eminent evolutionary success? His ingenious

answer to this excellent question brought him right back to mans great

ecological diversity. Humans, Mayr declared, had specialized in despe-

cialization. What was more, Man occupies more ecological niches than

any known animal. If the single species man occupies all the niches that

are open for a Homo-like creature, it is obvious that he cannot speciate

(emphasis mine). Mayr also noted something else very special about man,

something that, in his view at least, supported his reconstruction of human

phylogeny as an infinite recession of todays ubiquitous Homo sapiens back

into the past: Man is apparently particularly intolerant of competitors . . .

the elimination of Neanderthal man by the invading Cro-Magnon man is

only one example.

Mayr took questions at the end of his presentation. When asked (not

by a paleoanthropologist, of course) about how the notable morphological

differences found among fossil hominids could all be compressed into a

single genus, he finessed his answer by responding that since there are no

absolute generic characters, it is impossible to define and delimit genera

on a purely morphological basis. Nobody at the time saw fit to call him

on this. Nobody pointed out the obvious: that morphology was the only

thing that paleontologists had to work with, and that, while he might tech-

nically have been right about the nonexistence of absolute generic char-

acterswhatever exactly that meantfossil genera had to be recognized

from their morphology. Nor did anybody suggest that intolerance of com-

petition might be specifically a feature of Homo sapiens, distinguishing it

from even its closest relatives. And neither did anyone question any other of

Mayrs sweeping and hugely speculative declarationseither at the time, or

in the couple of years following the appearance in print of his provocative

comments.

Almost certainly, the reason for this supine acceptance of his many-sided

criticisms of their field is that Mayrs broadside had shocked the tiny elite of

paleoanthropologists into some long-overdue introspection. They finally be-

gan to realize that they and their predecessors had been operating in a theo-

retical vacuum, in which nobodyexcept perhaps Franz Weidenreichhad


72 The STrange CaSe of The riCkeTy CoSSaCk

bothered to think much either about the processes that might have under-

written the stories they were telling about their fossils, or about how their

operating assumptions fit in with what was known about how the rest of

Nature had evolved. And here was Mayr, the self-assured architect of the

Synthesis, with an eloquent and comprehensive analysis of their science: an

analysis that combined a nod to morphology with considerations of evolu-

tionary process, systematics, speciation theory, and ecologyall those key

factors that paleoanthropologists were now beginning to feel guilty about

having largely ignoredto produce a cogent and coherent statement about

human evolution. Without an intellectual fallback position, what could they

do but capitulate? Caught in this uncomfortable epistemological situation,

hardly anybody seemed to mind that Mayrs scenario was far from firmly

anchored in the study of the fossils themselves.

The major English-speaking exception to this instant surrender was

Robert Brooms younger associate John Robinson, who pointed out at some

length that the morphological heterogeneity among the gracile and robust

australopithsand some similarities he saw between some South African

and early Javan materialindicated at least two coexisting hominid lin-

eages in the Pliocene or early Pleistocene. And although Mayrs grudging

admission that Robinson indeed had a valid point was buried in a pile of

notes published in a journal that paleoanthropologists didnt read, once

Robinson had pointed this out most of his colleagues came to agree that

the robust australopiths were best excluded from Mayrs linear scheme. The

genus name Australopithecus continued to be used for all the gracile aus-

tralopiths (and for some paleoanthropologists, mainly Robinson, the ro-

bust offshoot continued to be called Paranthropus). Robinson himself also

continued to use the name Telanthropus (his quotes) for the mysterious,

very lightly built hominid fossils from Swartkransand by then also from

one section of Sterkfontein, which by the mid-1950s also had begun to pro-

duce some crudely flaked stone tools.

But that was about it. After that fateful year of 1950, paleoanthropolo-

gists in the English-speaking world dutifully lined up behind Mayrs con-

tention that, after the australopith stage (and probably well back into it),

hominid evolution had to all intents and purposes consisted of the pro-

gressive modification of a single central lineage. At any one point in time

that lineage had consisted of multiple geographical variants, but the whole

thing was consistently knit together by genetic interchange. Throughout,


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Strange Case Excerpt