Skeptics

"As a final footnote to life’s little joke, I remind readers that one other prominent (or at least parochially beloved) mammalian lineage has an equally long and extensive history of conventional depiction as a ladder of progress—yet also lives today as the single surviving species of a formerly more copious bush. Look in the mirror, and don’t be tempted to equate transient domination with either intrinsic superiority or prospects for extended survival."

"These arguments led Darwin to his denial of progress as a consequence of the “bare bones mechanics” of natural selection—for this process yields only local adaptation, often exquisite to be sure, but not universally advancing. The mammoth is every bit as good as an elephant—and vice versa. Do you prefer a marlin for its excellent spike; a flounder for its superb camouflage; an anglerfish for its peculiar “lure” evolved at the end of its own dorsal fin ray; a seahorse for its wondrous shape, so well adapted for bobbing around its habitat? Could any of these fishes be judged “better” or “more progressive” than any other? The question makes no sense. Natural selection can forge only local adaptation—wondrously intricate in some cases, but always local and not a step in a series of general progress or complexification."

"Our shenanigans, nuclear and otherwise, might easily lead to our own destruction in the foreseeable future. We might take most of the large terrestrial vertebrates with us—a few thousand species at most. We surely cannot extirpate 500,000 species of beetles, though we might make a significant dent. I doubt we could ever substantially touch bacterial diversity. The model organisms cannot be nuked into oblivion, or very much affected by any of our considerable conceivable malfeasances."

"A proper theory of morality depends upon the separation of intentions from results."

"Few intellectual tyrannies can be more recalcitrant than the truths that everybody knows and nearly no one can defend with any decent data (for who needs proof of anything so obvious). And few intellectual activities can be more salutary than attempts to find out whether these rocks of ages might crumble at the slightest tap of an informational hammer."

"People under assault, and hopelessly overmatched, often do the opposite of what propriety might suggest: they dig in when they ought to accommodate. We call this behavior “siege mentality.”"

"I like to think of myself as a tough-minded intellectual, a foe of all fuzziness from alien abductions to past-life regressions. I hate to think that an intellectual position, hopefully well worked out in the pages of this book, might end up as a shill for one of the great fuzzinesses of our age—so-called “political correctness” as a doctrine that celebrates all indigenous practice, and therefore permits no distinctions, judgments, or analyses."

"And yet I think that the Full House model does teach us to treasure variety for its own sake—for tough reasons of evolutionary theory and nature's ontology, and not from a lamentable failure of thought that accepts all beliefs on the absurd rationale that disagreement must imply disrespect. Excellence is a range of differences, not a spot. Each location on the range can be occupied by an excellent or an inadequate representative—and we must struggle for excellence at each of these varied locations. In a society driven, often unconsciously, to impose a uniform mediocrity upon a former richness of excellence—where McDonald's drives out the local diner, and the mega-Stop & Shop eliminates the corner Mom and Pop—an understanding and defense of full ranges as natural reality might help to stem the tide and preserve the rich raw material of any evolving system: variation itself."

"Phony psychics like Uri Geller have had particular success in bamboozling scientists with ordinary stage magic, because only scientists are arrogant enough to think that they always observe with rigorous and objective scrutiny, and therefore could never be so fooled—while ordinary mortals know perfectly well that good performers can always find a way to trick people."

"I would rather label the whole enterprise of setting a biological value upon groups for what it is: irrelevant, intellectually unsound, and highly injurious."

"The invalid assumption that correlation implies cause is probably among the two or three most serious and common errors of human reasoning."

"Very few people, including authors willing to commit to paper, ever really read primary sources—certainly not in necessary depth and comtemplation, and often not at all. […] When writers close themselves off to the documents of scholarship, and then 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 own intellectual traditions. You insert yourself, and your own organizing powers, into this history—and you become an acive agent, not merely a “reporter.”"

"Very little comes easily to our poor, benighted species (the first creature, after all, to experiment with the novel evolutionary inventions of self-conscious philosophy and art). Even the most “obvious,” “accurate,” and “natural” style of thinking or drawing must be regulated by history and won by struggle. Solutions must therefore arise within a social context and record the complex interactions of mind and environment that define the possibility of human improvement."

"I am particularly fond of Emmanuel Mendes da Costa's] Natural History of Fossils because this treatise, more than any other work written in English, records a short episode expressing one of the grand false starts in the history of natural science—and nothing can be quite so informative and instructive as a juicy mistake."

"[T]ruly grand and powerful theories […] do not and cannot rest upon single observations. Evolution is an inference from thousands of independent sources, the only conceptual structure that can make unified sense of all this disparate information. The failure of a particular claim usually records a local error, not the bankruptcy of a central theory. […] If I mistakenly identify your father's brother as your own dad, you don't become genealogically rootless and created de novo. You still have a father; we just haven't located him properly."

"Theories rarely arise as patient inferences forced by accumulated facts. Theories are mental constructs potentiated by complex external prods (including, in idealized cases, a commanding push from empirical reality). But the prods often include dreams, quirks, and errors—just as we may obtain crucial bursts of energy from foodstuffs or pharmaceuticals of no objective or enduring value. Great truth can emerge from small error. Evolution is thrilling, liberating, and correct. And Macrauchenia is a litoptern."

"Each and every loss becomes an instance of ultimate tragedy—something that once was, but shall never be known to us. The hump of the giant deer—as a nonfossilizable item of soft anatomy—should have fallen into the maw of erased history. But our ancestors provided a wondrous rescue, and we should rejoice mightily. Every new item can instruct us; every unexpected object possesses beauty for its own sake; every rescue from history's great shredding machine is—and I don't know how else to say this—a holy act of salvation for a bit of totality."

"I went to the movies to see Independence Day, the outer-space summer blockbuster of 1996. (Even the most committed intellectual can't survive on an unalloyed diet of Jane Austen remakes.)"

"Nearly anyone in this line of work would take a bullet for the last pregnant dodo. But should we not admire the person who, when faced with an overwhelmingly sad reality beyond personal blame or control, strives valiantly to rescue whatever can be salvaged, rather than retreating to the nearest corner to weep or assign fault?"

"A very sincere and serious freshman student came to my office with a question that had clearly been troubling him deeply. He said to me, “I am a devout Christian and have never had any reason to doubt evolution, an idea that seems both exciting and well documented. But my roommate, a proselytizing evangelical, has been insisting with enormous vigor that I cannot be both a real Christian and an evolutionist. So tell me, can a person believe both in God and in evolution?” Again, I gulped hard, did my intellectual duty, and reassured him that evolution was both true and entirely compatible with Christian belief—a position that I hold sincerely, but still an odd situation for a Jewish agnostic."

"When puzzled, it never hurts to read the primary documents—a rather simple and self-evident principle that has, nonetheless, completely disappeared from large sectors of the American experience."

"I have a great respect for religion, and the subject has always fascinated me […]. Much of this fascination lies in the stunning historical paradox that organized religion has fostered, throughout Western history, both the most unspeakable horrors and the most heartrending examples of human goodness in the face of personal danger. (The evil, I believe, lies in an occasional confluence of religion with secular power. The Catholic Church has sponsored its share of horrors, from Inquisitions to liquidations—but only because this institution held great secular power during much of Western history. When my folks held such sway, more briefly and in Old Testament times, we committed similar atrocities with the same rationales.)"

"I love these tales because, in more reasonable attributions of motive, they so beautifully embody a fundamental theme of historical explanation - that consequences of substantial import often arise from triggers of entirely different intent. In other words, current utility bears no necessary relationship with historical origin."

"When we look to presumed sources of origin for competing evolutionary explanations of the giraffe's long neck, we find either nothing at all, or only the shortest of speculative conjectures. Length, of course, need not correspond with importance. Garrulous old Polonius, in a rare moment of clarity, reminded us that "brevity is the soul of wit" (and then immediately vitiated his wise observation with a flood of woolly words about Hamlet's Madness.)"

"If the neck of the giraffe elongates an inch at a time, then the full panoply of supporting structures need not arise at every step. The coordinated adaptation can be built piecemeal. Some animals may slightly elongate the neck, others the legs; still others may develop stronger neck muscles. By sexual reproduction, the favorable features of different organisms may be combined in offspring."

"When scientists need to explain difficult points of theory, illustration by hypothetical example - rather than by total abstraction - works well (perhaps indispensably) as a rhetorical device. Such cases do not function as speculations in the pejorative sense - as silly stories that provide insight into complex mechanisms - but rather as idealized illustrations to exemplify a difficult point of theory. (Other fields, like philosophy and the law, use such conjectural cases as a standard device.)"

"The giraffe's neck supposedly supplies a crucial example for preferring natural selection over Lamarckism as a cause of evolution. But Darwin himself (however wrongly by later judgement) did not deny the Lamarckian principle of inheritance for characters acquired by use or lost by disuse. He regarded the Lamarckian mechanism as weak, infrequent, and entirely subsidiary to natural selection, but he accepted the validity of evolution by use and disuse. Darwin does speculate about the adaptive advantage of giraffe's necks, but he cites both natural selection and Lamarckism as probable causes of elongation."

"We may summarize the main line of this complexly meandering tale as a list of ironies - invoking the technical definition of irony as a statement where, for humorous or sarcastic effect, the intended meaning of a word becomes directly opposite to the usual sense..."

"Henry Fairfield Osborn, the dominant paleontologist of his era, and long time director of the American Museum of Natural History, gave the "standard version in his popular book of 1918, The Origin and Evolution of Life... "Lamarck attributed the lengthening of the [giraffe's] neck to the inheritance of bodily modifications caused by the neck-stretching habit. Darwin attributed the lengthening of the neck to the constant selection of individuals and races which were born with the longest necks. Darwin was probably right." …The version has held ever since."

"If we choose a weak and foolish speculation as a primary textbook illustration (falsely assuming that the tale possesses a weight of history and a sanction of evidence), then we are in for trouble - as critics properly nail the particular weakness, and then assume that the whole theory must be in danger if supporters choose such a fatuous case as a primary illustration."

"In his anti-Darwinian book... (and eponymously named The Neck of the Giraffe), Francis Hitching tells the story... "The need to survive by reaching ever higher for food is, like so many Darwinian explanations of its kind, little more than a post hoc speculation." Hitching is quite correct, but he rebuts a fairy story that Darwin was far too smart to tell - even though the tale later entered our high school texts as a "classic case" nonetheless."

"Eternal vigilance, as they say, is the price of freedom. Add intellectual integrity to the cost basis."

"Giraffes do use their long necks to browse leaves, at the tops of acacia trees - but such current function, no matter how vital, does not prove that the neck originally evolved for this purpose. The neck may have first lengthened in context of a different use, and then been coopted for better dining when giraffes moved into the open plains. Or the neck may have evolved to perform several functions at once. We cannot learn the reasons for historical origin simply by listing current uses."

"Why, then, have we been bamboozled into accepting the usual tale without questioning? I suspect two primary reasons: we love a sensible and satisfying story, and we are disinclined to challenge apparent authority (like textbooks!). But do remember that most satisfying tales are false."

"Darwinian evolution may be the most truthful and powerful idea ever generated by Western Science, but if we continue to illustrate our conviction with an indefensible, unsupported, entirely speculative, and basically rather silly story, then we are clothing a thing of beauty in rags - and we should be ashamed, "for the apparel oft proclaims the man.""

"Advocates for a single line of progress encounter their greatest stumbling block when they try to find a smooth link between the apparently disparate designs of the invertebrates and vertebrates."

"Arthropods and vertebrates share some broad features of general organization - elongated, bilaterally symmetrical bodies, with sensory organs up front, excretory structures in the back, and some form of segmentation along the major axis. But the geometry of major internal organs could hardly be more different... Arthropods concentrate their nervous system on their ventral (belly) side as two major cords running along the bottom surface of the animal. The mouth also opens on the ventral side, with the esophagus passing between the two nerve cords, and the stomach and remainder of the digestive tube running along the body above the nerve cords. In vertebrates, and with maximal contrast, the central nervous system runs along the dorsal (top) surface as a single tube culminating in a bulbous brain at the front end. The entire digestive system then runs along the body axis below the nerve cord."

"The inversion theory has a long and fascinating history in the discussion of vertebrate origins. The founding version dates to the early nineteenth century and became the centerpiece of a movement often called "transcendental biology," and centered on the attempt to reduce organic diversity to one or a very few archetypal building blocks that could generate all actual anatomies as products of rational laws of transformation. Some of Europe's greatest thinkers participated in this grand, if flawed enterprise. Goethe, Germany's preeminent poet-scientist, tried to explain the varied parts of plants as different manifestations of an archetypal leaf."

"In France, Étienne Geoffroy Saint-Hilaire attempted to portray the skeleton of vertebrates as a set of modifications upon an archetypal vertebra. In the 1820's, Geoffroy extended his ambitious plan to include annelids and arthropods under that same rubric. ...Vertebrates support their soft parts with an internal skeleton, but insects must live within their vertebrae (a reality, not a metaphor, for Geoffroy). This comparison led to... the claim that a vertebrate rib must represent the same organ as an arthropod leg - and that insects must therefore walk on their own ribs!"

"Geoffrey also recognized that the opposite orientations of gut and nervous system posed a problem for his claim that insects and vertebrates represent different versions of the same archetypal animal - and he proposed the first account of the inversion theory to resolve this threat to unification. ...Geoffroy pursued the... aim of establishing a "unity of type" that could generate both arthropods and vertebrates from the same basic blueprint. ...The single grand design includes a gut in the middle and the main nerve cords somewhere on the periphery."

"Later evolutionary theorists of linear progress had to advance the overtly physical and historical claim that an ancestral lineage of arthropods actually turned over to become the first vertebrates (for the classical statement of the inversion theory, see William Patten, The Grand Strategy of Evolution, 1920)."

"Gaskell could not abide this indecorous version of his beloved linear progress theory. He could not bear to imagine that the grand procession from jellyfish to man, orchestrated by an ever-increasing mass of nervous tissue, once paused in its stately and orderly march toward human consciousness in order to execute a fancy little flip, a clever jig of inversion, just at the sublime and definitive moment of entrance into the vertebral home stretch."

"Gaskell... had to keep his stately soldiers upright and uniformly oriented... by crafting the brain and spinal cord from an arthropod digestive tube, while forming a completely new gut below. ...Gaskell thought that his move would rescue the theory of linear progress, with its necessary transition of arthropod into vertebrate, from the absurdities of the old inversion theory."

"How ironic. In order to avoid the "nutty" theory of inversion, Gaskell invented the even odder notion of stomachs turning into brains with new guts forming below. No wonder then, that later biologists cast a plague on both speculative houses and opted instead for the obvious alternative: arthropods and vertebrates do not share the same anatomical plan at all, but rather represent two separate evolutionary developments of similar complexity from a much simpler common ancestor that grew neither a discrete gut nor a central nerve cord."

"Independent derivation meshed beautifully with the triumph, from the 1930's on, of a strict version of Darwinism based on the near ubiquity of adaptive design built by natural selection... Arthropods and vertebrates do share several features of functional design. But those similarities only reflect the power of natural selection to craft optimal structures independently in a world of limited biomechanical solutions to common functional problems - an evolutionary phenomenon called convergence."

"This new consensus seemed so compelling that Ernst Mayr, the dean of modern Darwinians, opened the ashcan of history for a deposit of Geoffrey's ideas about anatomical unity."

"Darwin himself told us in his last book (The Formation of Vegetable Mould Through the Action of Worms) that we should never underestimate the power of worms on the move. ...The inversion of a humble worm, especially when disturbed, may bring down empires. Shakespeare told us that "the smallest worm will turn being trodden on." And Cervantes wrote in his author's preface to Don Quixote that "even a worm when trod upon, will turn again." …Geoffrey, it seems, was correct after all - not in every detail, of course, but at least in basic vision and theoretical meaning. And the triumph of surprise, the inversion of nuttiness to apparent truth, stands as a premier example of the most exciting general development in evolutionary theory during our times."

"We can now determine, easily and relatively cheaply, the detailed chemical architecture of genes; and we can trace the products of these genes (enzymes and proteins) as they influence the course of embryology. In so doing we have made the astounding discovery that all complex animal phyla - arthropods and vertebrates in particular - have retained, despite their half-billion years of evolutionary independence, an extensive set of common genetic blueprints for building bodies."

"Many similarities of basic design among animal phyla, once so confidently attributed to convergence, and viewed as testimony to the power of natural selection to craft exquisite adaptation, demand the opposite interpretation that Mayr labeled as inconceivable: the similar features are homologies, or products of the same genes, inherited from a common ancestor and never altered enough by subsequent evolution to erase their comparable structure and function. The similarities record the constraining power of conserved history, not the architectural skills of natural selection independently pursuing an optimal design in separate lineages. Vertebrates are, in a certain sense, true brothers (or homologs) - not mere analogs - of worms and insects."

"Evolving life must experience a vast range of possibilities, based on environmental histories so unpredictable that no realized route - the pathway to consciousness in the form of Homo sapiens or Little Green Men, for example - can be construed as a highway to heaven, but must be viewed as a tortuous track rutted with uncountable obstacles and festooned with innumerable alternative branches. Any reasonably precise repetition of our earthly route on another planet therefore becomes wildly improbable even in a trillion cases."