This piece was originally published on AlterNet.

Atheists often point out that religious faith is closed off to evidence that contradicts it. What evidence would persuade atheists that their atheism was mistaken?

If I’m such an open-minded atheist — if I really am an atheist because I think the God hypothesis is unsupported by the evidence — what evidence for God would I accept? What would it take to change my mind?

Atheists often ask religious believers, “What evidence would convince you that you were mistaken?” We like to point out that religious beliefs are usually unfalsifiable — there’s no possible evidence that could prove them wrong, thus rendering them utterly useless. And even if they’re falsifiable in theory (as any belief in a 6,000 year old Earth ought to be), they wind up being unfalsifiable in practice, with an endless series of denialism and goalpost-moving and “God works in mysterious ways” waffling. We often point out that the very definition of religious faith is believing without evidence, even believing in spite of evidence that flatly contradicts the faith. We point out that, when asked “What would convince you that your belief was mistaken?”, the answer from believers is typically, “Nothing. Nothing would convince me that my God is not real. That’s what it means to have faith.” (Which makes accusing atheists of arrogance more than a little absurd… but that’s not important right now.)

And atheists like to point out that this isn’t true for us. We like to point out that atheists are open to the possibility that we might be wrong. We like to point out that the reason we don’t believe in God is that we haven’t seen good evidence for him… and that if we see better evidence, we’ll change our minds.

But I’ll admit that I’ve been lazy about spelling out what that evidence actually is. When the subject comes up, I’ve tended to point to the legendary (in atheist circles, anyway) essay on this subject, The Theist’s Guide to Converting Atheists, by Daylight Atheism blogger Ebonmuse. I’ve tended to just point to that piece, and say, “What he said. That’s more or less what I think.”

But that seems like cheating. If I’m going to insist that my atheism is falsifiable, I bloody well ought to be willing to think carefully about what, exactly, would falsify it. Not for some other really smart atheist — for me. And I ought to be willing to spell that out in public.

So it’s time to go out on a limb. It’s time to put up or shut up.

Here are the pieces of evidence that would convince me that God was real. Not necessarily that God was good, or worth worshipping — simply that he/ she/ it/they existed.

And here, side by side with that, are some of the kinds of evidence that would not convince me God or the supernatural exist. Kinds of evidence that are typically offered by believers in debates with atheists, so often it’s depressingly predictable. Kinds of evidence that flatly do not hold up. (All inspired, obviously, by the abovementioned Theist’s Guide to Converting Atheists. From which I am stealing this whole idea outright.)

An Unambiguous Message

What would convince me: If I saw an unambiguous message from God, I would be persuaded of his existence. If I saw writing suddenly appear in the sky, in letters a hundred feet high, saying “I Am God, I Exist, Here Is What I Want You To Do” — and if that writing were seen by every human being, written in whatever language they understand, comprehended in the same way by everyone who saw it — I would be persuaded that God existed. I’d be puzzled as to why he’d waited this long — why he’d decided to do it in 2010 and not at any other time in human history — but I’d still believe.

(And for the record: Yes, it’s possible that this could happen without God. It could hypothetically, for instance, be accomplished by a highly technologically advanced alien species. But I don’t think that would be the simplest explanation. If this phenomenon happened, “God” would, in my opinion, be a simpler explanation than “aliens” — and unless I saw good evidence that the writing was done by aliens, God would be the provisional conclusion I would come to.)

What would not convince me: I would not, however, be persuaded by ambiguous messages. I would not be persuaded by religious texts or teachings that contradict themselves, and that are easily interpreted in wildly different and even completely contradictory ways by different believers in that faith. Like, oh, say, every religious text I’ve ever read.

I would also not be persuaded by people saying, “The evidence is all around you! Look at the magnificence of life and the universe! It had to be created and shaped by something, because… well, it had to be! Isn’t it obvious?” Human minds are wired by evolution to see intention, even where no intention exists. Given this cognitive error; given that so much about life and the universe has already been explained by physical cause and effect; given the thorough consistency with which natural explanations for phenomena have replaced supernatural ones, thousands upon thousands of times over the course of history, when it has never once happened the other way around… given all this, I see no reason to interpret the existence of the physical universe as an unambiguous message from God.

Similarly, I would not be persuaded by the “first cause” argument, the argument from design, or the argument from fine tuning. Same reasons, basically.

And I would not be persuaded by a message that only I saw or heard. (At least… I hope I wouldn’t be. It’s possible that I could get hit by lightning or something and get my brain re-arranged in a way that made me think God existed. But I would be wrong to do so. If I ever get hit by lightning and decide that God exists, you all have my permission to print out this article and smack me over the head with it.)

“I feel it in my heart” is one of the worst pieces of evidence for God that I’ve seen. Our personal intuitions are important and valuable — but they’re far too flawed, far too subject to confirmation bias and other cognitive errors, to be the sole piece of evidence for anything in the external, non-subjective world. Especially when it comes to things that we really, really want to believe — like God and Heaven and immortality. If we care whether the things we believe about the world are true, we need to test our personal experiences and intuitions, using rigorous methods designed to filter these cognitive biases out.

Accurate Prophecies in Sacred Texts

What would convince me: If any sacred text in any religion made clear, unambiguous, accurate prophecies about the future — and did so consistently — I would be persuaded that this religion was divinely inspired. If there were a passage in Isaiah or Revelation, the Pyramid Texts or the Bhagavad Gita, that read, “And verily I say unto you, that 1,987 years after the death of Augustus Caesar, on the date of September 11, some followers of an Abrahamic religion that has not yet been founded will attack a city called New York that does not yet exist, by steering flying machines that have not yet been invented into two skyscrapers, whatever the hell those are” — and if that same sacred text made several other clear, accurate prophecies — I’d be convinced that God or some other divine being existed, and had inspired the text in question. (With the same “highly technologically advanced aliens” caveat noted above.)

What would not convince me: I would not, however, be persuaded by vague prophecies that could easily be interpreted in an infinite number of ways, and that can be twisted and shoehorned in after an event to make it seem like that event is what was being predicted. (Like, oh, say, to pick one example completely at random, Nostradamus.)

I would also not be persuaded by one lucky hit among numerous misses. If I saw the abovementioned 9/11 prophecy in a sacred text — but this same sacred text also prophesized that the flying machines would be invented in the year 1066, and that in 1501 all people would sprout green tentacles for three months, and that within a hundred years of the tentacle incident the continent of Antarctica would be swallowed by hamsters… I’d be surprised, I’d stop and take notice, but ultimately I wouldn’t be convinced.

I would definitely not be persuaded by very broad, obvious predictions. “The current empire will someday fall”… well, yes. Empires rise and fall. “There will be a great drought”… well, yes. Droughts happen. You don’t need God to tell you that. Any nimrod can figure that out. Self-fulfilling prophecies would also not convince me. As Ebonmuse pointed out in the Theist’s Guide: “The Jewish people returned to their homeland in Israel just as the Bible said they would, but this isn’t a genuine prediction — they did it because the Bible said they would. The predicted event can’t be one that people could stage.”

And I would not be persuaded by religious texts that were written after a prophecy had been made, conveniently making it seem as if the previous prophecy had been magically fulfilled. When the Old Testament predicted that the Messiah would have such-and-such characteristics, and the authors of the New Testament knew that the Old Testament had made these predictions, and they wrote the story of Jesus after the fact in a way that shoehorned him into those predictions… that’s a teensy bit unconvincing. To say the least.

Accurate Science in Religious Texts

What would convince me: If any sacred text in any religion were consistently accurate in its writings about science — including scientific knowledge that was not known at the time the text was written — I would be persuaded that this religion was divinely inspired. If there were a passage in Isaiah or Revelation, the Pyramid Texts or the Bhagavad Gita, that read, “And verily I say unto you, that the earth orbits the sun despite how it appears to the naked eye, and the sun is simply another of the millions upon millions of stars that appear in the sky, and the continents slowly drift through the oceans, and energy is equal to mass times the speed of light squared”… I’d be convinced that God or some other divine being existed, and had inspired the text in question. (Again, with the same “space aliens” caveat noted above.)

What would not convince me: I would not, however, be persuaded by vaguely worded passages that could be twisted after the fact to fit into current scientific knowledge. The fact that the Bible starts with the words “In the beginning” does not mean it’s accurately describing the Big Bang. Please. Absolutely nothing in Genesis implies anything about the Big Bang… and plenty of stuff in Genesis completely contradicts it. Such as the bit about the Earth being created before the stars. Give me a break.

And again, I would not be persuaded by one lucky hit among eleventy kajillion misses. If a sacred text got it right about the earth orbiting the sun, but got it laughably wrong about botany and zoology and epidemiology and geology and genetics and physics… I would remain, to say the least, unimpressed.

The One Successful Religion

What would convince me: If the believers in one particular religion had noticeably better lives than the believers in any other religion — in ways that couldn’t be accounted for by social or economic or other natural factors — I would be convinced that this religion was true. If believers in, say, the Mormon faith, or the Baha’i faith, or the Wisconsin Evangelical Lutheran Synod, were found to be far healthier, wealthier, and happier than believers in other faiths, if their prayers came true significantly more often, if they had far fewer accidents and birth defects and genetic diseases and pediatric cancer — and this difference was statistically significant, much greater than could be accounted for by higher wealth or social status or something — I would be persuaded that God existed, and that this faith was the correct one, and that God was rewarding these believers for the correctness of their faith.

And if one religion consistently won all its holy wars with all other religions — again, in ways that couldn’t be explained by better military technology or a larger population or other social/ economic/ natural factors — that would get me believing in a heartbeat.

I might not be persuaded to worship this God, or to believe that he was good. I’d be more than a little baffled as to why he hadn’t made his message of Mormonism or Baha’i-ism or Wisconsin Evangelical Lutheran Synodism clearer to everyone. I’d actually think he was kind of a dick. But I’d sure be persuaded that he existed.

What would not convince me: I would not, however, be persuaded by one religion doing better than another for obvious social or economic or other natural reasons. Yes, Episcopalians tend to be wealthier than, say, Baptists. There are lots of obvious, entirely natural explanations for this. None of them have to do with Episcopalians being God’s chosen people.

And I would definitely not be persuaded by believers parading all the times that their prayers came true… and then, when all the times that their prayers weren’t answered got pointed out, responding with something like, “God moves in mysterious ways,” or, “God answers all prayers, but sometimes the answer is No.” Sorry, but you can’t have it both ways. You don’t get to count the hits and ignore or rationalize the misses. That’s what we call confirmation bias. And it’s definitely cheating.

Inexplicably Accurate Information Gained During Near-Death or Other Supposedly Psychic Experiences

What would convince me: This is a slightly different category — it’s more about evidence for an immaterial soul than evidence for God — but I’m going to bring it up anyway. If a person who was near death, or who was having some other sort of supposed psychic experience, were to gather information that could not possibly have been gathered in any physical way — and this was rigorously tested under careful conditions designed to screen out confirmation bias and cold readings and the unconscious sending of messages and other cognitive or experimental errors (not to mention outright fraud), and the experience could be consistently replicated under similarly rigorous testing conditions — I would be persuaded that human consciousness was not simply a product of the human brain, and that it had a non-physical component that could hypothetically survive death. If someone near death or in a trance or whatever could reliably, testably report on the contents of a locked safe… that would persuade me of the existence of the soul.

What would not convince me: I would not, however, be persuaded by anecdotal reports of these experiences. Casual observers are too — is there a nice word for “gullible”? I suppose there isn’t — too unfamiliar with natural explanations for supposedly supernatural events, too unaware of the kinds of experimental errors that can make these experiences seem real, too subject to confirmation bias, too incomplete in their understanding of probability, and far, far too eager to believe that the soul is real and they aren’t going to die. So these experiences would need to be rigorously tested and replicated, by people with experience in the kinds of cognitive and experimental errors that supposed psychic experiences are consistently subject to. (The reality is that whenever these types of experiences have been subjected to careful testing under good, scientific conditions, they never, ever, ever pan out. Ever.)

And I would definitely not be persuaded by the mere fact that some people have strange experiences when they’re near death. Being near death is an altered state of consciousness, and people have weird experiences when our brains are altered. We have weird experiences under all sorts of conditions: exhaustion, stress, distraction, trance-like repetition, optical illusion, sleep deprivation, sensory deprivation, sensory overload… any of these, and more, can create vivid “perceptions” that are entirely disconnected from external reality. You don’t have to be mentally ill, or even on drugs, to have weird experiences of things that aren’t there. And the oxygen deprivation and other physical changes that happen to the brain when it’s near death are definitely enough to do the trick. This one isn’t even close to being convincing. It makes absolutely no sense at all.

Is The Bar Too High?

Now, some believers will probably argue that my standards set the bar too high. They’ll argue that I’ve created standards of evidence that are obviously not being met: that I’ve created a counter-factual world in which God might exist, but that clearly is not the world we live in.

To which I reply: Yes. That’s my whole freaking point. The whole reason I don’t believe in God is that there is not one scrap of good, solid evidence supporting the God hypothesis. The whole reason I don’t believe in God is that every piece of evidence anyone has ever shown me in support of the God hypothesis has completely sucked. The whole reason I don’t believe in God is that these criteria — criteria that would be completely reasonable for any other hypothesis — are not being met.

As many atheists point out: If God were real, we wouldn’t be having this discussion. If God were real, it would be freaking obvious. If God were real, nobody would be an atheist. Nobody would even disagree about religion. The most obvious explanation for God’s existence not being ridiculously self-evident is that God does not exist. As Julia Sweeney says in her brilliant performance piece Letting Go of God, “The world behaves exactly as you expect it would, if there were no Supreme Being, no Supreme Consciousness, and no supernatural.”

And it’s absurd to argue that this bar is too high. If God were real — if there really were a God who created the universe and/or intervenes with it magically — none of this would be beyond him. I mean — he created the entire, 93- billion- light- years- across universe out of nothing! Surely he could make hundred-foot-high letters appear in the sky, or create a sacred text with scientific and prophetic accuracy, or consistently answer the prayers of the Wisconsin Evangelical Lutheran Synod! To argue that any bar is too high for him, that any standard of evidence is too rigorous for him, is ridiculous on the face of it.

Besides, just because God hasn’t offered these pieces of evidence so far doesn’t mean he never will. Maybe he’ll decide that he tried sending his message with the flood, and he tried again with Jesus… but obviously none of that worked, humans can be kind of thick-headed sometimes. So hey, why not try that “hundred-foot letters in the sky” thing this atheist chick keeps gassing on about?

If he does, I’ll change my mind.

In the meantime, I remain unconvinced.

Take The Challenge

So I’ve gone out on my limb. What about you?

If you’re an atheist — what evidence would convince you that your atheism was mistaken? Or that it was probably mistaken?

And if you’re a believer… what evidence would convince you that your belief was mistaken? Or that it was probably mistaken?

If you think your faith is falsifiable — if you would not answer the question, “What would convince you that your faith was mistaken?” by saying, “Nothing would change my mind, that’s what it means to have faith” — then take Ebonmuse’s challenge. If you prepare a list of things you’d accept as proof that atheism is true, and you post it on the Internet, he’ll link to it, and open it to discussion on his blog.

Until you do, please don’t accuse atheists of being close-minded, or arrogant, or unwilling to consider new ideas and evidence.

It just makes you look silly.

Addendum: When I first posted this piece on AlterNet, a number of commenters argued that, when it comes to many of the pieces of evidence that would persuade me out of my atheism, the space alien hypothesis would be a much more plausible explanation than the God hypothesis. I think a case could certainly be made for that position.

But to some extent, I’m drawing the line here to prove a point. Yes, an argument could be made that “aliens” would be a more plausible explanation for the skywriting and so on than “God.” But even when I give religion the benefit of the doubt in the evidence game; even when I err on the side of giving religion greater credibility than it possibly deserves; even when I say, “If this skywriting thing happened, I would be persuaded to believe” — it still falls short.