Leonardo’s Mountain of Clams and the Diet of Worms (17 page)

The debate arose in the late 1850s and lasted with full force into
the 1860s, sputtering out by the time Owen wrote his gorilla monograph in 1865. Owen and Huxley duked it out both in writing and in public appearances, notably at the same 1860 British Association meeting where, according to legend and unsupported by fact, Huxley also destroyed Bishop “Soapy Sam” Wilberforce in an initial altercation over Darwinism (the exchange took place, but without a clear victor).
The debate spilled vigorously and copiously into general culture, as the public and press delighted in watching two of Britain’s greatest scientists acrimoniously debating such an important issue (the status of humans in nature) by wrangling about parts of the brain unknown to all and endowed with such wonderfully amusing names as “hippocampus minor.” Charles Kingsley, featuring the hippocampus
debate in his 1863 children’s classic
The Water Babies
, emphasized the humor implicit in the conjunction of arcane anatomical mumbo-jumbo with a theme of such conceptual and emotional importance. Kingsley writes of Professor Ptthmllnsprts (Put-them-all-in-spirits), his parody of Huxley:

On May 18, 1861,
Punch
published a quite accurate account of the issue in doggerel verse, beginning:

And indeed it was! Private letters give a good account of the animosity. Huxley wrote that he would “nail that mendacious humbug . . . like a kite to the barn door.” Owen described one of their public altercations to a friend: “Prof. Huxley disgraced the discussions by which scientific differences of opinion are rectified by imputing falsehood on a matter in which he differed from
me. Until he retracts this imputation as publicly as he made it I must continue to believe that, in making it, he was merely imputing his own base and mendacious nature.”

The “official” account of the debate can be summarized in a paragraph: Huxley approached the controversy like a military general, out to upstage an older enemy. He organized several colleagues to dissect the brains of various
apes and monkeys in search of the structures that Owen had pronounced unique to humans. Huxley himself studied the brain of the South American spider monkey, a “lower” primate on the traditional scale. They also scoured published literature, searching both for Owen’s distortions or selective quotations, and for prior proof of the three structures in nonhuman primates. In short, they found abundant
evidence for all three structures in various primates. Owen, according to legend, eventually shut up and licked his wounds.

Owen’s tactics clearly led him to disaster. (Both Owen and Huxley came from lower middle-class backgrounds, but Owen had ingratiated himself into upper circles, to his enormous practical benefit, receiving a rent-free residence directly from Queen Victoria and, beginning
in the early 1840s, an annual civil list pension, all achieved while Huxley struggled financially and grew bitterly jealous. Never doubt the centrality of social class for understanding Victorian life.) As a
nouveau arrivé
in the upper classes, Owen felt that he had to obey perceived norms for imperious disregard of upstarts. He fought for his positions, and against Huxley, but not with the same
vigor, and with none of Huxley’s overt organization. Owen largely tut-tutted among his noble friends, and lost precious ground.

Owen’s tactics evidently failed, but were his arguments so bad? I will not attempt to deny the usual reading—that Huxley and his phalanx found all three structures in the brains of nonhuman primates, therefore disproving Owen’s criteria of uniqueness. But was Owen really
so stupid, and so defeated? I don’t think so. I would like to raise two points for balance, and partly in Owen’s defense—the first well discussed by Rupke and others, the second (so far as I know) not previously covered in the literature.

First, how did Owen respond to Huxley and company’s discovery of the three structures in apes and monkeys? Did he just deny their findings, or suffer in silence?
In fact, Owen made a potentially fair reply. He had been stating for years (though he had conveniently omitted the claim in several publications at the height of the hippocampus debate) that virtually every feature of humans has a homologous expression in closely related chimps and gorillas. (Owen had coined the term
homology
in the late 1840s to identify features of identical anatomical origin
in different creatures, whatever the degree of functional divergence—wings of bats with front legs of horses, for example. We now attribute homology to evolutionary descent from a common ancestor.) But admission of homology does not require application of the same name to the relevant feature in two organisms, for functional divergence might legitimately permit a different term. For example, calling
the bat’s forearm a wing doesn’t obligate us to state that all mammals have wings because all carry homologs of the bat’s forearm bones.

Owen invoked a sneaky version of this purely terminological point to worm out of his defeat—but we must at least credit the technical validity of his claim. In the 1865 gorilla monograph, he admits that the three structures do exist in apes, but in such rudimentary
state, and in such different form from their expression in humans, that all must receive a different name—just as horses don’t have wings. Thus, we can still say that apes don’t have a posterior lobe, a posterior cornu, and a hippocampus minor—even though they possess homologs of all these human structures!

Owen begins by allowing pervasive homology: “In the Gorilla . . . the homologue of every
organ and of almost every named part in Human anatomy is present.” He then discusses how a gorilla brain might be topologically transformed to a human brain, almost nonchalantly admitting at the end that the three structures already exist in gorillas!

I could accept Owen’s redefinition as clever and honorable, but for two points. First, he implies that he
doesn’t have to give the same name to the three features in apes because they are so poorly developed. But Huxley and colleagues had shown that some apes develop these features to equal strength with their expression in humans. Second, if Owen had taken this position all along, then we could blame Huxley for unsubtlety. But, in fact, Owen didn’t begin by admitting rudimentary homologs of the three
features in apes, and merely claiming that strong human development required a separate name. He really did deny that the structures existed
at all
in apes. Owen wrote in his 1859 lecture:

I do think, particularly in this context of focal conclusion,
that “peculiar” means “unique”—and that Owen did shift his ground by verbal ploy, thus illustrating the valid part of Huxley’s mistrust and anger.

But the second point, previously overlooked in our large literature, does corroborate an important part of Owen’s argument—one with wrenching implications in our current reality. Huxley was clearly right in demonstrating the three structures in other
apes, but his central presentation of the argument for evolutionary continuity between apes and humans, published most prominently in
Man’s Place in Nature
(1863), rests upon two false arguments (one as sneaky as Owen’s later attempt to cover his ass), and both well refuted by Owen in his gorilla monograph of 1865.

Man’s Place in Nature
presents the strongest defensible version of smooth evolutionary
transition between apes and humans. Huxley admits the undeniable gap in brain size, with smaller-bodied humans carrying a brain three times as large as that of much weightier gorillas, but correctly identifies this disparity as a gulf in quantity alone, for all parts of the brain are homologous in apes and humans. Huxley then, and with equal justice, argues that a different
quantity
of brain need
not account for a true gulf in
quality
of mental operations, for such a claim would confuse correlation with causality. Perhaps, Huxley states, human cognitive superiority resides in some unidentified difference of cellular or microarchitectural function, and not in disparity of bulk alone.

Huxley then presents his two linked arguments. First, he hammers home by brute force, listing feature after
feature, his key claim for continuity: the gap between the lowest ape and the chimp or gorilla is far greater than the corresponding gap between these “highest” apes and humans—so we are just one small step farther along in the sequence of apes:

But Huxley’s argument seems unfair and even a tad self-serving within the context that both he and Owen shared: a belief that groups of related organisms should be ranked on a scale from lower
to higher. (Our current denial of this scheme is, of course, irrelevant to our analysis of the logical structure of Huxley and Owen’s arguments.) Owen properly refuted Huxley by pointing out that he had made a false comparison of disparate things—apples and oranges in the current cliché. The gap between gorilla and human amounts to one step, but the separation of “lower” primates from chimps and
gorillas encompasses scores of omitted intermediates. If I were trying to minimize the gap between step 50 and 51 in a series by arguing that the separation between step 1 and step 50 is even greater, you would properly laugh me to scorn and say, “Don’t load the dice inevitably in your favor; compare the right things. Tell me about the gap between 49 and 50 versus 50 and 51. A step must be compared
with a step, not with the entire series!” If the gorilla-human step exceeds the distance between any two adjacent primates, then I may regard humans as something special. Owen writes:

I think
that Huxley sensed the weakness of his argument, for he introduced a second supposed clincher in conjunction and support: the gap between gorilla and average human may be large, but if we order all human variation in a hierarchical ranking of races, from the “lowest” Negro to the “highest” Caucasian, then the gap closes, for the step from gorilla to lowest human becomes less than the space between
lowest and highest
Homo sapiens.
(Please understand that I am using Huxley’s own terms and quoting the conventional wisdom of his day within the restricted community of scientists—that is, white males of privilege.) Huxley wrote:

I do not think that Huxley, a racial liberal by the standards of his time, advanced this argument with intent to impugn entire groups of human beings. Rather, he was trying to plug a hole in his central argument for evolutionary continuity by finding some way
to fill the embarrassingly large space in cranial capacity between gorilla and average human.

This complex world of ours, this vale of tears, lies awash in irony. Just as bad things happen to good people, decent folks also advance logically fallacious and morally dubious claims in support of good arguments. Huxley stood on the side of the angels: he tried to advance the cause of human evolution
by documenting continuity with our closest animal relatives. He closed his case with a magnificent prose flourish in describing the great range of design within the primate order, from the lowest lemur to our exalted selves: