This piece was originally published on AlterNet.

“Just look around you. Look at life, and the universe, and everything. Doesn’t it seem like it had to have been designed?”

A lot of arguments for religion are very bad indeed. A lot of arguments for religion aren’t even arguments: they’re deflections, excuses for why the believer isn’t making an argument, bigoted insults, expressions of wishful thinking, complaints that atheists are mean bad people to even ask for an argument, heartfelt wishes that atheists would just shut up.

But some believers do take the question “Why do you believe in God?” seriously. Some believers don’t want to believe just out of blind faith or wishful thinking; they care about whether the things they believe are true, and they think that the question “What evidence do you have to support this belief?” is a valid one. And they think they have good answers for it. They think they have positive evidence for their spiritual beliefs, and they’re happy to explain that evidence and defend it.

The argument from design — the argument that life had to have been designed, because it just looks so much like it was designed — leads the list of these answers. According to Michael Shermer’s How We Believe, the argument from design is the single most common reason that religious believers give for why they believe.

So since these people are taking atheists’ questions about their religion seriously, I want to return the favor, and take their religious answer seriously.

And I want to talk about why this is really, really not a good answer. At all. Even a little bit.

Have You Heard Of This Darwin Fellow?

The argument from design argues that the evidence for God lies in the seemingly inexplicable complexity and functionality and balance of life: of individual life forms, of specific biological organs and systems, of the ecosystem itself. “Look at the eye!” the argument goes. “Look at an ant colony! Look at a bat’s sonar! Look at symbiotic relationships between species! Look at the human brain! They work so well! They do such astonishing things! Are you trying to tell me that these things just… happened? How can you possibly explain all that without a designer?”

Not to be snarky, but: Have you heard of this Darwin fellow?

I’m assuming that I’m not talking to creationists here. Creationists definitely do not count as people who care about reason and evidence and whether what they believe is consistent with reality. I’m assuming that I’m talking here to reasonably educated people, people who accept the basic reality of the theory of evolution… but who still think that God had to have been involved in it somehow. I’m assuming that I’m talking to people who understand that the theory of evolution is supported by a massive body of evidence from every relevant field of science (and from some that you might not think of as relevant)… but who still think that evolution, while a jolly clever idea, is still not quite sufficient to explain the complexity and diversity and exquisite high functioning of biological life.

To those people, I say: You really need to study evolution a little more carefully.

The theory of evolution is completely sufficient to explain the complexity and diversity and exquisite high functioning of biological life. That’s exactly what it does. The whole point of evolutionary theory is that it explains exactly how life came to be the complex and amazingly balanced web of interconnections that it is, with species beautifully adapted to their environments — not through design, but through natural selection and descent with modification. It explains it beautifully, and elegantly, and with no need for any supernatural designer to explain anything. Descent with modification; the survival and reproduction of life forms who are best able to survive and reproduce; great heaping gobs of time. That’s all it takes. (Here’s a good primer on what evolution is and how it works; for a more detailed explanation, you can check out Why Evolution Is True by Jerry A. Coyne, or The Greatest Show On Earth: The Evidence for Evolution by Richard Dawkins, or Evolution: What the Fossils Say and Why It Matters by Donald R. Prothero, or… oh, you get the idea.) The more familiar you become with evolution, the more you understand that it is more than sufficient to explain what seems at first glance to be design in biological life.

And in fact, biological life is an excellent argument against God or a designer.

Why? Because so much of this supposed “design” of life is so ridiculously piss-poor.

The Three Stooges School of Design

Yes, there are many aspects of biological life that astonish with their elegance and function. But there are many other aspects of biological life that astonish with their clumsiness, half-assedness, inefficiency, “fixed that for you” jury-rigs, pointless superfluities, glaring omissions, laughable failures, and appalling, mind-numbing brutality. (Here’s a very entertaining short list.) I mean… sinuses? Blind spots? External testicles? Backs and knees and feet shoddily warped into service for bipedal animals? (She said bitterly, getting up to do her physical therapy on her bad knee.) Human birth canals barely wide enough to let the baby’s skull pass… and human babies born essentially premature because if they stayed in utero any longer they’d kill their mothers coming out? (Which sometimes they do anyway?) A vagus nerve that travels from the neck down through the chest only to land back up in the neck… travelling ten to fifteen feet in the case of giraffes? Digger wasps laying their eggs in the living bodies of caterpillars… and stinging said caterpillars to paralyze but not kill them, so the caterpillars die a slow death and can nourish the wasps’ larvae with their living bodies? The process of evolution itself… which has brutal, painful, violent death woven into its every fiber?

You’re really saying that all of this was designed, on purpose, by an all-powerful God who loves us?

Evolution looks all this epic fail, and explains it neatly and thoroughly. In the theory of evolution, living things don’t have to be perfectly or elegantly “designed” to flourish. All that matters is that they be functional enough to survive and reproduce, and to do so more effectively than their competitors. In fact, in the theory of evolution, not only is there no expectation that the “designs” be perfect or elegant — there is every expectation that they wouldn’t be, since every new generation has to be a minor adaptation on the previous one, and there’s no way to wipe the slate clean and start over. And the comfort or happiness of living things matters not in the slightest bit to the process of evolution… unless it somehow enhances the ability of that living thing to survive and reproduce.

The argument from design looks at all this epic fail, and answers, “Ummm… mysterious ways?”

Before and After Science

If we didn’t know about evolution, the argument from design might have some validity. Even Richard Dawkins, hard-assed atheist that he is, has acknowledged that atheism, while still logically tenable before Darwin, became a lot more intellectually fulfilling afterwards.

But once you know about evolution — not just about Darwin, but about the rich and thorough, broad-ranging and finely-detailed understanding of life that evolution has blossomed into in the 150 years since “On The Origin of Species” — the argument from design collapses like a house of cards in a hurricane.

The theory of evolution provides a powerful, beautiful, consistent explanation for the appearance of design in biological life, one that can not only explain the past but predict the future. And it’s supported by an overwhelming body of evidence from every relevant field of science, from paleontology to microbiology to epidemiology to anatomy to genetics to geology to physics to… you get the point. The argument from design explains nothing that evolution can’t explain better. It has massive, gaping holes. It has no predictive power whatsoever. And it has not a single scrap of positive evidence supporting it: not one piece of evidence suggesting the intervention of a designer at any point in the process. All it has to support it is the human brain’s tendency to see intention and design even where none exists, leading to the vague feeling on the part of believers that life had to have been designed because… well… because it just looks that way.

And if “it just looks that way” is the only argument you can make for why life was designed, you’re going to have to find a better argument.

Also in this series:
Why “Everything Has a Cause” Is a Terrible Justification for God’s Existence