Leonardo’s Mountain of Clams and the Diet of Worms (2 page)

I make this humanistic confession (or profession, really) because I have tried, in the prefaces to each of my essay volumes (this is the eighth in a series that will reach ten before the millennium calls a halt), to figure out how the present effort
differs from (and, I hope, builds upon) the varying themes of preceding books. I began with emphasis on evolutionary basics, proceeded to evolutionary implications, social and philosophical usages, the interaction of predictive rules with contingent history to form the unique and surprising patterns of life’s history, and the interaction of human history with natural environments.

This eighth
volume, as usual, includes all these themes, but differs in emphasis primarily in my own increasing comfort with my unconventional approach to “natural history” writing, as outlined above. If any overarching theme pervades this body of writing (now standing at 270 successive monthly essays), I suppose that a groping effort toward the formulation of a humanistic natural history must unite the disparity.
I think that I have been reluctant to recognize, address, or even admit this feature, either to myself or to my readers, because such an approach does contravene a deep (and usually unstated) convention in writing about nature. We are supposed to love nature for itself, and we are, therefore, presumably charged with the task of characterizing and interpreting nature (as she is) so that interested
people with less expertise can learn new information and draw appropriate messages, both factual and ethical. Well, I do love nature—as fiercely as anyone who has ever taken up a pen in her service. But I am even more fascinated by the complex level of analysis just above and beyond (and I do mean “abstracted from,” not “better than”)—that is, the history of how humans have learned to study
and understand nature. I am primarily a “humanistic naturalist” in this crucial sense.

Of course I yearn for answers to all the puzzles, great and small, that build the order (and wondrous disorder) of nature “out there”—an order that our intellectual ancestors could only read (understandably) as a proof of God’s existence and benevolent intent. And I am convinced that such answers exist, if
only to be seen “through a glass darkly,” given the necessary interposition of human history, sociology, and psychology between the “real” world, and any abstractions of disembodied logic that might manipulate and order our observations. (In this sense, no practicing scientist can be a pure “relativist,” although I trust the more sophisticated and self-analytical among us know that “pure” observation,
“unsullied” by human foibles and preferences, can only rank as idealized legend.)

But I prefer to emphasize the interaction of this outside world with something unique in the history of life on Earth—the struggle of a conscious and questioning agent to understand the whys and wherefores, and to integrate this knowledge with the meaning of its own existence. That is, I am enthused by nature’s
constitution, but even more fascinated by trying to grasp how an odd and excessively fragile instrument—the human mind—comes to know this world outside, and how the contingent history of the human body, personality, and society impacts the pathways to this knowledge.

A map of the roadblocks—imposed by the evolutionary limitations of an instrument clearly not designed for this style of inquiry,
and then joined with the improbable and unrepeatable contingencies that built our modern technological society—holds just as much interest as an accurate map of nature’s geography. Moreover, a humanistic focus on how we know about nature—rather than an “objective” account, unattainable in any case, of how nature “is”—gives an essayist a “whole ‘nother” level of juicy material, for we lose nothing
of the primary topic, the world as we find it, and gain all the foibles and fascination of
how
we find it so.

As another benefit of this humanistic focus, we acquire a surprising source of rich and apparently limitless novelty from the primary documents of great thinkers throughout our history. But why should any nuggets, or even flakes, be left for intellectual miners in such terrain? Hasn’t
the
Origin of Species
been read untold millions of times? Hasn’t every paragraph been subjected to overt scholarly scrutiny and exegesis?

Let me share a secret rooted in general human foibles, and in the faint tinge of anti-intellectualism that has always pervaded American culture. Very few people, including authors willing to commit to paper, ever really read primary sources—certainly not in
necessary depth and completion, and often not at all. Nothing new here, but this shortcutting propensity of the ages has been abetted in our “journalistic” era by a lamentable tendency to call experts, rather than to read and ponder—yet another guarantee of authorial passivity before secondary sources, rather than active dialogue, or communion by study, with the great thinkers of our past.

I
stress this point primarily for a practical, even an ethical, reason, and not merely to vent my spleen. When writers close themselves off to the documents of scholarship, and rely only on seeing or asking, they become conduits and sieves rather than thinkers. When, on the other hand, you study the great works of predecessors engaged in the same struggle, you enter a dialogue with human history and
the rich variety of our intellectual traditions. You insert yourself, and your own organizing powers, into this history—and you become an active agent, not merely a “reporter.” Then, and only then, can you become an original contributor, even a discoverer, and not only a mouthpiece.

What could be more democratic than the principle that nuggets of real discovery abound in primary sources, located
in such accessible places as major university and city libraries, for those willing to do the work and develop the skills. (And there’s the rub. I do, of course, acknowledge the impediment for most Americans that many of these works, representing the ecumenical range of international scholarship, have never been translated into English—a fact that should be a spur to study, and not a barrier.)
Good anatomists have told me that novel and important observations can still be made by dissecting a common frog, despite millions of prior efforts spanning several centuries. I can attest that all major documents of science remain chock-full of distinctive and illuminating novelty, if only people will study them—in full and in the original editions. Why would anyone
not
yearn to read these works;
not hunger for the opportunity? What a thrill, whatever the outcome in personal enlightenment, to thus engage the greatest thinkers and doers of our past, to thumb the pages of their own printings, to speculate about past readers who pondered the same copies with the differing presuppositions of other centuries, as the candle of nighttime illuminated their silent labor.

Of the six parts in this
humanist’s natural history of evolutionary essays, the first four—on art and science, mini-biographies, human prehistory with emphasis on paleolithic cave art, and human history from a naturalist’s standpoint—emphasize our side, though several focus on particular organisms, as in chapter 9 on giant deer (“Irish elks”) painted on cave walls, chapter 11 on Bahamian land snails for a fable about Columbus,
and chapter 12 on the dodo’s fate, made even sadder by human insult added to the ultimate injury of extirpation. The essays of the last two sections—on evolutionary theory, and on perspectives of other organisms—focus on the nonhuman side (again with such exceptions, as chapter 14 on papal statements about evolution, chapter 15 on the contrast of Robert Boyle and Charles Darwin on natural
design, and chapter 18 on Percival Lowell versus Alfred Russel Wallace on Martian canals and the true domination of earthly life by bacteria.)

All these essays are grounded in a precious paradox that has defined the best of the genre ever since Montaigne: intimate and accurate detail—the foundation of most good essays—serves as a source of delight in itself, and also as a springboard to discourse
about generalities of broadest scope. I would never dare to take on “the nature of truth” by frontal assault and abstract generalization—for fear of becoming an empty, tendentious buffoon, pontificating about the unanswerable and undefinable. But the subject must rivet us, and we can legitimately “sneak up on” (and even genuinely illuminate) this great issue by discussing how Darwin and his creationist
American soulmate Dana constructed alternative taxonomies for toothed birds that should not have existed under previous concepts of reality, but had just been discovered as fossils (chapter 5). Similarly, if I tackled “the nature of tolerance” head-on, naked of intriguing and specific illustration, I would sound like a vain preacher crying in the wilderness (negative definition!). But if
I confess some childhood humor in juxtaposing, for alliteration as well as content, the Diet of Worms with the Defenestration of Prague (chapter 13), then a seemingly superficial, even ridiculous, union wins legitimacy for joint illustration, and provides fair access to factual and moral dimensions of the general topic.

These essays probe, arrange, join, and parry the details within a diverse
forest of data, located both in nature and in the documents of human struggle—all to access an inherently confusing but infinitely compelling world. As I survey the contents of this eighth volume, I find that I have followed four primary strategies to promote these details into coherent frameworks with sufficient generality to incite an essay.

1. In some cases, an intense study of original sources
yields genuine discovery, despite the paradox that materials for a solution have always been patent. The story of nonuse for the giraffe’s neck by early evolutionists had not been documented before (chapter 16), and surprising absences often reveal as much as unrecognized presences. I located a new dimension, largely in favor of the “vanquished” Owen and not the “victor” Huxley, in the great
hippocampus debate that animated evolutionary discussion in the 1860s (chapter 6). Dana’s important theory of cephalization, and its link with his natural theology (in interesting contrast with Darwin’s developing alternative), has never been elucidated, in part because Dana scattered his views through so many short and technical papers (chapter 5).

But I am, I confess, most proud of the opening
title essay on Leonardo’s paleontology. The excellence and prominence of his observations on fossils have been recognized—and dutifully honored in all accounts, popular, textbook, and technical—for more than a century, since the full publication of his private notebooks in the 1880s. But no one had identified the special reasons (based on his own, and largely medieval, views of the earth as analogous
to a living body) for his intense focus on fossils, and for the placement of his statements in a codex largely devoted to the nature of water. So these wonderful observations had stood out, disembodied from context, and misinterpreted as the weird anachronisms of a transcendent and largely unfathomable genius. But the full document of the Leicester Codex sets the proper context, when read
in its entirety and understood by the physics of Leonardo’s own time.

2. In most cases, I do not report observations never made before, but try to place unfamiliar (or even well-known) items into a novel context by juxtaposition with other subjects not previously viewed as related—invariably in the service of illuminating a general point about the practice of science, the structure of nature,
or the construction of knowledge. In reviewing the essays for this volume (not planned as an ensemble when first written, but collected from my monthly series for
Natural History
magazine), I noticed that I had most often made such a juxtaposition by the minimal method of pairing, or contrast between two—perhaps a general mode of operation for the human mind, at least according to several prominent
schools of research (discussed here in the context of paleolithic cave art in chapter 8). For example, all the essays in part 2 on mini-biographies, although focusing on one previously unappreciated or misunderstood character, interpret their subject by his contrast with a standard figure—Linnaeus and the eighteenth-century English Jewish naturalist Mendes da Costa (chapter 4), James D. Dana
and his British soulmate Darwin (chapter 5), Richard Owen versus T. H. Huxley (chapter 6), and the tragic Russian genius Vladimir Kovalevsky (and his equally tragic and more brilliant wife, Sophia, one of the greatest mathematicians of the nineteenth century) with Darwin on the potential of error to illuminate scientific truth (chapter 7).

Many other essays also pursue this strategy of illumination
by paired contrast, with novelty in the joining: Boyle and Darwin on natural theology and evolution (chapter 15); Percival Lowell versus Alfred Russel Wallace on the canals of Mars and the uniqueness of life (chapter 18); sloths and vultures as prototypes for traits that we, in our parochial and irrelevant way, judge as negative but yearn to understand (chapter 20); the Diet of Worms and the
Defenestration of Prague as events of European history, related by more than their shared initial
D
and funny names (chapter 13); the Abbé Breuil and André Leroi-Gourhan for two sequential and maximally contrasting (but strangely similar) theories about the genesis of cave art (chapter 8); the great artist Turner and the prime engineer Brunel on the similarity of art and science (chapter 2); a
forgotten theory about the origin of vertebrates with stunning new data to validate an even older view, all as an entrée to the subject of major evolutionary transitions and the prejudices that impede our understanding of this topic (chapter 17); the dodo of Mauritius and the first New World victims of Western genocide (chapter 12); and the striking difference between two popes in their common willingness
to support the factual truth of evolution (chapter 14).

3. If my second category works by joining disparate details, a third strategy operates by careful excavation—elucidation by digging rather than elucidation by joining. As the mineshaft widens and deepens, one may reach a richness of detail justifying promotion to an essay because the requisite generality has been attained by one of two routes:
(1) By casting a truly novel, or at least sufficiently different, light on an old subject, so that readers become willing to devote renewed interest, and may even obtain some provocative insight (Darwin always wrote to his creationist friends that he dared not expect to change their minds, but did hope to “stagger” them a bit)—as when intricate details of the life cycle of the maximally “degenerate”
parasite
Sacculina
suggest new attention to the fallacies of evolutionary progress (chapter 19), and when the subtle (and almost entirely unreported) distinctions in the affirmation of evolution by two very different popes (Pius XII and John Paul II) illuminate the old and overly discussed issue of proper relationships between science and religion (chapter 14). (2) By gaining the “right” to address
a large and general issue through the new perspective of previously unapplied detail (as in the examples of chapters 5 and 13, previously discussed, and chapter 10 on the relevance of new data about the multiplicity of human species until 30,000–40,000 years ago and the consequent oddity of our current status as a single species spread throughout the globe) for a discussion of predictability
versus historical contingency in the evolution of self-conscious life on Earth.