Read Online Bully for Brontosaurus by Stephen Jay Gould - Free Book Online Page B
Authors: Stephen Jay Gould
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both doesn’t care much about us and often operates in a random manner). I call this bias “adaptationism”—the notion that everything must fit, must have a purpose, and in the strongest version, must be for the best.
The final line of Handel’s chorus is, of course, a quote from Alexander Pope, the last statement of the first epistle of his Essay on Man , published twenty years before Handel’s oratorio. Pope’s text contains (in heroic couplets to boot) the most striking paean I know to the bias of adaptationism. In my favorite lines, Pope chastises those people who may be unsatisfied with the senses that nature bestowed upon us. We may wish for more acute vision, hearing, or smell, but consider the consequences.
If nature thunder’d in his op’ning ears
And stunn’d him with the music of the spheres
How would he wish that Heav’n had left him still
The whisp’ring zephyr, and the purling rill!
And my favorite couplet, on olfaction:
Or, quick effluvia darting thro’ the brain,
Die of a rose in aromatic pain.
What we have is best for us—whatever is, is right.
By 1859, most educated people were prepared to accept evolution as the reason behind similarities and differences among organisms—thus accounting for Darwin’s rapid conquest of the intellectual world. But they were decidedly not ready to acknowledge the radical implications of Darwin’s proposed mechanism of change, natural selection, thus explaining the brouhaha that the Origin of Species provoked—and still elicits (at least before our courts and school boards).
Darwin’s world is full of “terrible truths,” two in particular. First, when things do fit and make sense (good design of organisms, harmony of ecosystems), they did not arise because the laws of nature entail such order as a primary effect. They are, rather, only epiphenomena, side consequences of the basic causal process at work in natural populations—the purely “selfish” struggle among organisms for personal reproductive success. Second, the complex and curious pathways of history guarantee that most organisms and ecosystems cannot be designed optimally. Indeed, to make an even stronger statement, imperfections are the primary proofs that evolution has occurred, since optimal designs erase all signposts of history.
This principle of imperfection has been a major theme of my essays for several years. I call it the panda principle to honor my favorite example, the panda’s false thumb. Pandas are the herbivorous descendants of carnivorous bears. Their true anatomical thumbs were, long ago during ancestral days of meat eating, irrevocably committed to the limited motion appropriate for this mode of life and universally evolved by mammalian Carnivora. When adaptation to a diet of bamboo required more flexibility in manipulation, pandas could not redesign their thumbs but had to make do with a makeshift substitute—an enlarged radial sesamoid bone of the wrist, the panda’s false thumb. The sesamoid thumb is a clumsy, suboptimal structure, but it works. Pathways of history (commitment of the true thumb to other roles during an irreversible past) impose such jury-rigged solutions upon all creatures. History inheres in the imperfections of living organisms—and thus we know that modern creatures had a different past, converted by evolution to their current state.
We can accept this argument for organisms (we know, after all, about our own appendixes and aching backs). But is the panda principle more pervasive? Is it a general statement about all historical systems? Will it apply, for example, to the products of technology? We might deem this principle irrelevant to the manufactured objects of human ingenuity—and for good reason. After all, constraints of genealogy do not apply to steel, glass, and plastic. The panda cannot shuck its digits (and can only build its future upon an inherited ground plan), but we can abandon gas lamps for electricity and horse
The final line of Handel’s chorus is, of course, a quote from Alexander Pope, the last statement of the first epistle of his Essay on Man , published twenty years before Handel’s oratorio. Pope’s text contains (in heroic couplets to boot) the most striking paean I know to the bias of adaptationism. In my favorite lines, Pope chastises those people who may be unsatisfied with the senses that nature bestowed upon us. We may wish for more acute vision, hearing, or smell, but consider the consequences.
If nature thunder’d in his op’ning ears
And stunn’d him with the music of the spheres
How would he wish that Heav’n had left him still
The whisp’ring zephyr, and the purling rill!
And my favorite couplet, on olfaction:
Or, quick effluvia darting thro’ the brain,
Die of a rose in aromatic pain.
What we have is best for us—whatever is, is right.
By 1859, most educated people were prepared to accept evolution as the reason behind similarities and differences among organisms—thus accounting for Darwin’s rapid conquest of the intellectual world. But they were decidedly not ready to acknowledge the radical implications of Darwin’s proposed mechanism of change, natural selection, thus explaining the brouhaha that the Origin of Species provoked—and still elicits (at least before our courts and school boards).
Darwin’s world is full of “terrible truths,” two in particular. First, when things do fit and make sense (good design of organisms, harmony of ecosystems), they did not arise because the laws of nature entail such order as a primary effect. They are, rather, only epiphenomena, side consequences of the basic causal process at work in natural populations—the purely “selfish” struggle among organisms for personal reproductive success. Second, the complex and curious pathways of history guarantee that most organisms and ecosystems cannot be designed optimally. Indeed, to make an even stronger statement, imperfections are the primary proofs that evolution has occurred, since optimal designs erase all signposts of history.
This principle of imperfection has been a major theme of my essays for several years. I call it the panda principle to honor my favorite example, the panda’s false thumb. Pandas are the herbivorous descendants of carnivorous bears. Their true anatomical thumbs were, long ago during ancestral days of meat eating, irrevocably committed to the limited motion appropriate for this mode of life and universally evolved by mammalian Carnivora. When adaptation to a diet of bamboo required more flexibility in manipulation, pandas could not redesign their thumbs but had to make do with a makeshift substitute—an enlarged radial sesamoid bone of the wrist, the panda’s false thumb. The sesamoid thumb is a clumsy, suboptimal structure, but it works. Pathways of history (commitment of the true thumb to other roles during an irreversible past) impose such jury-rigged solutions upon all creatures. History inheres in the imperfections of living organisms—and thus we know that modern creatures had a different past, converted by evolution to their current state.
We can accept this argument for organisms (we know, after all, about our own appendixes and aching backs). But is the panda principle more pervasive? Is it a general statement about all historical systems? Will it apply, for example, to the products of technology? We might deem this principle irrelevant to the manufactured objects of human ingenuity—and for good reason. After all, constraints of genealogy do not apply to steel, glass, and plastic. The panda cannot shuck its digits (and can only build its future upon an inherited ground plan), but we can abandon gas lamps for electricity and horse
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