Gould, Darwin and Paley Meet the Invisible Hand

dered economy in the laissez-faire system, you do not regulate from on high 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 analogue 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 the hecatomb of such a system applied without restraint to our own affairs. 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:

He generally indeed neither intends to promote the public interest, nor knows how much he is promoting it.... He intends only his own gain, and he is in this, as in many other cases, led by an invisible hand to promote an end which was no part of his intention.

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 spinoffs 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 evolution 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 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 versus natural evils). Paley writes:

The order of generation proceeds by something like a geometrical progression. The increase of provision, under circumstances even the most advantageous, can only assume the form of an arithmetic series. Whence it follows, that the population will always overtake the provision, will pass beyond the line of plenty, and will continue to increase till checked by the difficulty of procuring subsistence.

(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 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 line is central to Smith's argument and has always been well known. 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 (although 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 loathe 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 understand. 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:

The hinges in the wings of an earwig, and the joints of its antennae, are as highly wrought, as if the Creator had nothing else to finish. We see no signs of diminution of care by multiplicity of objects, or of distraction of thought by variety. We have no reason to fear, therefore, our being forgotten, or overlooked, or neglected.
I can offer only two responses, both, I think, powerful and quite conducive to joyous optimism, if this be your fortunate temperament. We may lose a great deal of easy, unthinking, superficial comfort in the rejection of Paley's God. But think what we gain in toughness, in respect for nature by knowledge of our limited place, in appreciation for human uniqueness by recognition that moral inquiry is our straggle, not nature's display. Think also what we gain in increments of real knowledge--and what could be more precious--by knowing that evolution has patterned the history of life and shaped our own origin.

Thomas Henry Huxley faced the same dilemma more than 100 years ago. Chided by his theologian buddy Charles Kingsley for abandoning the traditional solace of religion in Paley's style, Huxley replied:

Had I lived a couple of centuries earlier I could have fancied a devil scoffing at me...and asking me what profit it was to have stripped myself of the hopes and consolations of the mass of mankind? To which my only reply was and is--Oh devil! truth is better than much profit.

And a gain of such magnitude is no barleycorn.

Stephen Jay Gould teaches biology, geology, and the history of science at Harvard University.