Excerpted from A Devil's Chaplain: Reflections on Hope, Lies, Science, and Love with permission of Houghton Mifflin and the author.

Darwin was less than half joking when he coined the phrase Devil's Chaplain in a letter to his friend Hooker in 1856:

What a book a Devil's Chaplain might write on the clumsy, wasteful, blundering low and horridly cruel works of nature.

A process of trial and error, completely unplanned and on the massive scale of natural selection, can be expected to be clumsy, wasteful and blundering. As I have put it before, the racing elegance of cheetahs and gazelles is bought at huge cost in blood and the suffering of countless antecedents on both sides. Clumsy and blundering though the process undoubtedly is, its results are opposite. There is nothing clumsy about a swallow; nothing blundering about a shark. What is clumsy and blundering, by the standards of human drawing boards, is the Darwinian algorithm that led to their evolution. As for cruelty, here is Darwin again, in a letter to Asa Gray of 1860:

I cannot persuade myself that a beneficent and omnipotent God would have designedly created the Ichneumonidae with the express intention of their feeding within the living bodies of Caterpillars.

Darwin's Ichneumonidae sting their prey not to kill but to paralyse, so their larvae can feed on fresh (live) meat. As Darwin clearly understood, blindness to suffering is an inherent consequence of natural selection, although on other occasions he tried to play down the cruelty, suggesting that killing bites are mercifully swift. But the Devil's Chaplain would be equally swift to point out that if there is mercy in nature, it is accidental. Nature is neither kind nor cruel but indifferent. Such kindness as may appear emerges from the same imperative as the cruelty. In the words of one of Darwin's most thoughtful successors, George C. Williams:

With what other than condemnation is a person with any moral sense supposed to respond to a system in which the ultimate purpose in life is to be better than your neighbor at getting genes into future generations, in which those successful genes provide the message that instructs the development of the next generation, in which that message is always `exploit your environment, including your friends and relatives, so as to maximize our genes' success', in which the closest thing to a golden rule is `don't cheat, unless it is likely to provide a net benefit'?

...I prefer to agree that natural selection is the dominant force in biological evolution, admit its unpleasantness, and fight against it as a human being. I hear the bleak sermon of the Devil's Chaplain as a call to arms. As an academic scientist I am a passionate Darwinian, believing that natural selection is, if not the only driving force in evolution, certainly the only known force capable of producing the illusion of purpose which so strikes all who contemplate nature. But at the same time as I support Darwinism as a scientist, I am a passionate anti-Darwinian when it comes to politics and how we should conduct our human affairs. I have always held true to the closing words of my first book, 'We, alone on earth, can rebel against the tyranny of the selfish replicators.' If you seem to smell inconsistency or even contradiction, you are mistaken. There is no inconsistency in favouring Darwinism as an academic scientist while opposing it as a human being; any more than there is inconsistency in explaining cancer as an academic doctor while fighting it as a practising one. For good Darwinian reasons, evolution gave us a brain whose size increased to the point where it became capable of understanding its own provenance, of deploring the moral implications and of fighting against them. Every time we use contraception we demonstrate that brains can thwart Darwinian designs. If, as my wife suggests to me, selfish genes are Frankensteins and all life their monster, it is only we that can complete the fable by turning against our creators. Yes, man can be vile too, but we are the only potential island of refuge from the implications of the Devil's Chaplain: from the cruelty, and the clumsy, blundering waste. For our species, with its unique gift of foresight--product of the simulated virtual-reality we call the human imagination--can plan the very opposite of waste with, if we get it right, a minimum of clumsy blunders. Yes, says the matured Chaplain, the historic process that caused you to exist is wasteful, cruel and low. But exult in your existence, because that very process has blundered unwittingly on its own negation. Only a small, local negation, to be sure: only one species, and only a minority of the members of that species; but there lies hope. .. The great Russian-American geneticist Theodosius Dobzhansky said:

In giving rise to man, the evolutionary process has, apparently for the first and only time in the history of the Cosmos, become conscious of itself.

So, the Devil's Chaplain might conclude, Stand tall, Bipedal Ape. The shark may outswim you, the cheetah outrun you, the swift outfly you, the capuchin outclimb you, the elephant outpower you, the redwood outlast you. But you have the biggest gifts of all: the gift of understanding the ruthlessly cruel process that gave us all existence; the gift of revulsion against its implications; the gift of foresight--something utterly foreign to the blundering short-term ways of natural selection and the gift of internalizing the very cosmos.

Safety and happiness would mean being satisfied with easy answers and comforts, living a warm comfortable lie. The daemonic alternative urged by my matured Devil's Chaplain is risky. You stand to lose comforting delusions: you can no longer suck at the pacifier of faith in immortality. To set against that risk, you stand to gain `growth and happiness'; the joy of knowing that you have grown up, faced up to what existence means; to the fact that it is temporary and all the more precious for it.