Eight Little Piggies (16 page)

Paley also provided some powerful theoretical arguments against evolution by use. If the elephant’s short neck implies a great advantage for a long nose, all well and good. But what can a poor proto-elephant do with one-tenth of a trunk:

I accept Paley’s arguments and might even be tempted to entertain his conclusions if he had truly accomplished his proper goal of refuting all logically possible alternatives. I believe that he did consider and dismiss all the potential refutations that he could conceive. But now we come to the crux of this essay. True originality is almost always an addition to the realm of the previously conceivable, not a mere permutation of possibilities already in hand. Progress in knowledge is not a tower to heaven built of bricks from the bottom up, but a product of impasse and breakthrough, yielding a bizarre and circuitous structure that ultimately rises nonetheless.

Paley missed a third alternative. We can scarcely blame him. The alternative is weird and crazy, laughable really. No sane person would build anything by such a cruel and indirect route. This third alternative can only work if you have lots of time to spare, and if you are not wedded to the idea that nature must be both efficient and benevolent. The third alternative, like the second, identifies natural evolution as the source of good design, thereby sinking Paley’s central conviction that adaptation must imply creation by divine fiat. But instead of viewing evolution as purposeful and positive movement towards the desired goal, this third alternative builds adaptation negatively—by eliminating all creatures that do not vary fortuitously in a favored direction, and preserving but a tiny fraction to pass their lucky legacy into future generations.

As I said, this third alternative is grossly inefficient and defies the logic of a clockwork universe, built by our standards and reasoning. No wonder it never entered Paley’s head. The only thing going for this third view—the only reason for even raising such an unpleasant topic here—is the curious fact that nature seems to work this way after all. Nobody ever called this method elegant, but the job gets done. We call this third view “natural selection,” or Darwinism. Darwin himself commented most forcefully upon the inefficient and basically unpleasant character of his process, writing to his friend Joseph Hooker in 1856: “What a book a devil’s chaplain might write on the clumsy, wasteful, blundering, low, and horribly cruel works of nature!”

The key to understanding Darwin’s third alternative lies with a word, unfortunately almost extinct in English, but deserving a revival—hecatomb. A hecatomb is, literally, a massive sacrifice involving the slaughter of one hundred oxen—a reference to ancient Greek and Roman practices. By extension, a hecatomb is any large slaughter perpetrated for a consequent benefit. Natural selection is a long sequence of hecatombs. Individuals vary in no preferred direction about an average form for the population. Natural selection favors a small portion of this spectrum. Lucky individuals in this portion leave more surviving offspring; the others die without (or with fewer) issue. The average form moves slowly in the favored direction, bit by bit per generation, through massive elimination of less favored forms.

The process might not be so inefficient if the hecatomb only occurred once at the beginning or if the sacrifice diminished from generation to generation. Suppose, for example, that the few survivors of the first hecatomb then automatically produced offspring with tendencies to vary in the favored direction. But Mendelian inheritance doesn’t work this way. The few survivors of the first elimination yield offspring that also vary at random about the new average. Thus, the hecatomb in the second generation, and in all subsequent sortings, may be just as intense.

We may use an analogy to symbolize the inefficiency of natural selection by hecatomb. Suppose that a population will be better adapted if it can move from A to B. In direct Lamarckian models, including the only evolutionary scheme that Paley managed to conceptualize, the movement is direct, purposeful, and positive. Members of the population get a push and just walk from A to B. In the clumsy, wasteful, blundering, low, and horribly cruel Darwinian hecatomb, each individual stands at spot A and falls at random. If he happens to fall right along the line to B, he survives to the next trial. All individuals who fall off the line—the vast majority—are summarily shot. After a round of reproduction among the few survivors of this first hecatomb, the second trial begins. Standing now at one body length along the path to B, all individuals fall at random again—and the process continues. The hecatomb is equally pronounced in each round, and the population moves but one body length towards its goal each time. The population will eventually get to point B, but would any engineer favor such a poky and punitive device? Can you blame the divine Paley for not even imagining such a devilish mechanism?

I do not contrast Darwin with Paley as an abstract rhetorical device. Darwin, as quoted above, revered Paley during his youth. In a courageous act of intellectual parricide, he then overthrew his previous mentor—not merely by becoming an evolutionist, but by constructing a particular version of evolutionary theory maximally disruptive of Paley’s system and deepest beliefs.

I can imagine two revolutionary ways—one more radical than the other—to overturn Paley’s comfortable and comforting belief that God made us all with shapes and habits beautifully adapted to our modes of life. You might argue that Paley was wrong, that animals are not generally well designed, and that if you insist on seeing God’s work in the massive imperfection of nature, then perhaps you ought to revise your notion of divinity. This would be a radical argument, but Darwin devised an even more disturbing version.

Secondly, you might argue (as Darwin actually did) that Paley was quite right: Animals are well adapted to their modes of life. But this good fit is not an emblem of God’s benevolence, rather an indirect result of the horrid system of multiple hecatombs known as natural selection. What a bitter pill for Paley—for Darwin allows that Paley described the look of nature correctly, but then argues that the mechanism for this appearance has a mode of action, and an apparent moral force, directly contrary to the intent and benevolence of the God of natural theology.

Where did Darwin get such a radical version of evolution? Surely not from the birds and bees, the twigs and trees. Nature helped, but intellectual revolutions must also have ideological bases. Scholars have debated this question for more than a century, and our current “Darwin industry” of historians has moved this old discussion towards a resolution. The sources were many, various, and exceedingly complex. No two experts would present the same list with the same rankings. But all would agree that two Scottish economists of the generation just before Darwin played a dominant role: Thomas Malthus and the great Adam Smith himself. From Malthus, Darwin received the key insight that growth in population, if unchecked, will outrun any increase in the food supply. A
struggle for existence
must therefore arise, leading by
natural selection
to
survival of the fittest
(to cite all three conventional Darwinian aphorisms in a single sentence). Darwin states that this insight from Malthus supplied the last piece that enabled him to complete the theory of natural selection in 1838 (though he did not publish his views for twenty-one years).

Adam Smith’s influence was more indirect, but also more pervasive. We know that the Scottish economists interested Darwin greatly and that, during the crucial months of 1838, while he assembled the pieces soon to be capped by his Malthusian insight, he was studying the thought of Adam Smith. The theory of natural selection is uncannily similar to the chief doctrine of laissez-faire economics. (In our academic jargon, we would say that the two theories are “isomorphic”—that is, structurally similar point for point, even though the subject matter differs). To achieve the goal of a maximally ordered economy in the laissez-faire system, you do not regulate from above by passing explicit laws for order. You do something that, at first glance, seems utterly opposed to your goal: You simply allow individuals to struggle in an unfettered way for personal profit. In this struggle, the inefficient are weeded out and the best balance each other to form an equilibrium to everyone’s benefit.

Darwin’s system works in exactly the same manner, only more relentlessly. No regulation comes from on high; no divine watchmaker superintends the works of his creation. Individuals are struggling for reproductive success, the natural analog of profit. No other mechanism is at work, nothing “higher” or more exalted. Yet the result is adaptation and balance—and the cost is hecatomb after hecatomb after hecatomb. (I call Darwin’s system more relentless than Adam Smith’s because human beings, as moral agents, cannot bear these hecatombs. We therefore never let laissez-faire operate without some constraint, some safety net for losers. But nature is not a moral agent, and nature has endless time.)

Adam Smith embodied the guts of his theory—his core insight—in a wonderful metaphor, one of the truly great lines written in the English language. Speaking of an actor in the world of laissez-faire, Adam Smith states:

Such a lovely image: The “invisible hand” that produces order, but doesn’t really exist at all, at least in any direct way. Darwin’s theory uses the same invisible hand, but formed into a fist as a battering ram to eliminate Paley’s God from nature. The very features that Paley used to infer not only God’s existence, but also his goodness, are, for Darwin, but spin-offs of the only real action in nature—the endless struggle among organisms for reproductive success, and the endless hecatombs of failure.

In this light, we may finally return to poor Paley and feel the poignancy of his inability even to conceptualize Darwin’s third alternative—the argument that finally, and permanently, brought his system down. He stood so close, but just didn’t have the conceptual tools to put the pieces together. (I do not suggest that Paley would have become a Darwinian if he had recognized the third way. He would surely have rejected evolution by hecatomb, just as he had attacked descent by purposeful step. Yet I remain fascinated by his failure to conceptualize the Darwinian mode at all, for the essence of genius lies in the rare ability to think in new dimensions orthogonal to old schemes, and we must dissect both failures and successes in order to understand this most precious feature of human intellect.)

Darwin received his greatest inspiration from Thomas Malthus and Adam Smith. Paley knew their work as well, yet he didn’t draw the implications. For Malthus, Paley actually cites the key line that inspired Darwin’s synthesis in 1838 (but in the context of a passage on civil vs. natural evils). Paley writes:

(At this point, Paley adds a footnote: “See this subject stated in a late treatise upon population”—obviously Malthus.)

The influence of Adam Smith is not quite so explicit. But I was powerfully moved (and inspired to write this essay) when I read Adam Smith’s great metaphor in Paley’s more effusive prose and differing intent. I quoted the line early in this essay: “I never see a bird in that situation, but I recognize an invisible hand, detaining the contented prisoner from her fields and groves for a purpose.”

I cite this correspondence as a symbol, not a proof. I realize that it offers no evidence for Paley imbibing the metaphor from Smith. The phrase is obvious enough, and could be independently invented. (Nonetheless, the metaphor of the invisible hand is central to Smith’s argument and has always been so recognized.
The Wealth of Nations
was published in 1776—an easy date for Americans to remember—a full generation before
Natural Theology
. So perhaps Paley had caught the rhythm from Smith.) The two usages are diametrically opposed, hence the poignancy of the comparison. Paley’s invisible hand is God’s explicit intent (though He works, in this case, indirectly through the bird’s instinct, and not by a palpable push). Smith’s invisible hand is the
impression
of higher power that doesn’t actually exist at all. In Darwin’s translation, the invisible hand dethrones the God of natural theology.

For some, this tale of shifting usages and ideas may seem a dull exercise in antiquated thought. Yet we have never stopped fighting the same battles, seeking the same solaces, rejecting the same uncomfortable truths. Why are some of us so loath to accept evolution at all, despite overwhelming evidence? Why are so many of us who do accept evolution so unable to grasp the Darwinian argument, or so unwilling, for emotional reasons, to live with it even if we do understand?

This situation may be frustrating for someone like me who has spent a professional lifetime working with the power of Darwinian models and who feels no moral threat in their potential truth (for a fact of nature cannot challenge a precept of morality)—frustrating perhaps, but not hard to comprehend. We leave Paley’s world with reluctance because it offered us such comfort, and we enter Darwin’s with extreme trepidation because the sources of solace seem stripped away. Consider the happy moral that Paley draws from good design and its divine manufacture: