I suppose it's a little silly to spend an entire blog post arguing against deism. After all, of all the religious beliefs out there, it's the one that's most consistent with the evidence. And it's almost certainly the one that does the least harm. In fact, deism pretty much is atheism -- except for the "believing in God" part.
But -- for reasons I'll explain in a moment -- I'm going to argue against it anyway. I don't care about it nearly as much as I do about other religious beliefs... but I care enough to spend a blog post on it.
Deism, for those who aren't familiar, is the belief that the Universe was created by a god; but once said Universe was created, God no longer had anything to do with it. God has a plan, but that plan is proceeding without God's intervention. He/she/it brought physical existence and the laws of physics and whatnot into being... and stopped there.
So for any practical purposes, deism is indistinguishable from atheism. An entirely non-interventionist god -- one who doesn't intervene even with any afterlife we might or might not have, much less with this life -- is, in any useful day- to- day sense, utterly indistinguishable from no god at all.
But for that exact reason, I think deism is logically indefensible.
Because a deistic god is essentially indistinguishable from no god at all, it is an entirely untestable, unfalsifiable hypothesis. Even more so than more common religious beliefs. Regular religious beliefs typically suffer from a great degree of unfalsifiability... but they do make some claims about how God acts on the world. Claims that tend to be slippery and goalpost- moving and heavily reliant on mysterious ways, to be sure... but claims nonetheless.
A belief in a deistic God doesn't. Deism essentially says, "God exists... but saying that God exists implies absolutely nothing about the world. God exists, but his/ her/ its existence is completely indistinguishable from his/ her/ its nonexistence." Totally untestable, totally unfalsifiable. With conventional religious beliefs, a world without God would be very different indeed from a world without God. With deism, there's no difference at all.
Now, a deist god supposedly answers the question of how all this Universe stuff got here in the first place. But in fact, it really just begs that question. Any questions about the Universe that the deist God hypothesis supposedly answers -- how did it get here, how did something come out of nothing, if it just always existed how is that possible -- have to be asked about God as well. It doesn't answer those questions; it just pushes them back one level, to God instead of the universe. If you can say that God just always existed, or that God somehow just came into being out of nothingness, then there's no reason you can't say that about the universe as well.
I suppose you could argue that a deist god answers the question of why believers believe; why people feel the presence of God even though there's no good evidence for him. Except that it doesn't. Given the fallibility of intuition and its tendency to tell us what we want or expect to hear, people's personal feelings and intuitions don't make a good argument for a deist God, any more than they do for an interventionist God. In fact, intuition is actually a less good argument for a deist God... since with a deist God, you have to ask the question, "If God isn't intervening in any way, shape, or form, then how is it that I can feel his/ her/ its presence?" The whole "this is how our brains work, we're wired to see patterns and intentions even where none exist, and to see what we expect and hope to see" thing makes a better explanation for these feelings and intuitions than the God hypothesis does... regardless of whether the God in question is interventionist or not.
The deistic God hypothesis isn't necessary. It doesn't answer any questions that the not-God hypothesis doesn't answer. Plus it presents a whole new set of unanswered and unanswerable questions -- such as how exactly God created the universe out of nothing, and why God doesn't intervene even though he/ she/ it clearly has the power to. And when your Hypothesis A doesn't answer any more questions than Hypothesis B, and it presents extra unanswered questions that Hypothesis B doesn't present, and it has extra entities and layers of complexity in the mix that Hypothesis B doesn't have... then that's a hypothesis you probably want to let go of.
But again -- why do I care? If deism is essentially indistinguishable from atheism, why do I care about it enough to bother criticizing it?
I care for the same reason I care about progressive, non-bigoted, science- positive religion.
I care because it gives legitimacy to the idea that it's okay to believe in undetectable supernatural entities, without any evidence to support that belief.
I care because it gives legitimacy to the idea that it's okay to believe in undetectable supernatural entities, simply because you feel it intuitively.
I care because it gives legitimacy to the idea that it's okay to believe in undetectable supernatural entities, simply because you want to: because you find the idea of a god comforting, and because you find the idea of there not being a god weird and upsetting.
It's not just that deism gives legitimacy to the basic concept of God and religious belief. It's that it gives legitimacy to these faulty forms of reasoning; the ones that keep getting used to defend the more obviously indefensible forms of religion. It gives legitimacy to unfalsifiable hypotheses, and prioritizing intuition over evidence, and wishful thinking.
And I'm not okay with that.
I do think deism is often a gateway religion; a step that people go through when they're in the process of letting religion go. I can't remember now where I read this, but I was recently reading some former Christian minister talking about how, as he thought about it harder and looked at it more carefully, the evidence for the God he'd been raised to believe in was looking increasingly weak and inconsistent... until finally his God had been reduced to an entirely deistic one, a God who was out there somewhere but was completely detached from human reality. At which point, he clung to his belief for a little longer... and was then finally able to let go.
It seems like this happens with a lot of people. I get that. And I'm basically okay with it. I don't expect every fervent believer, or even lukewarm believer, to immediately relinquish every scrap of their belief the first time they hear a good argument for atheism. People need to go through their process -- I certainly did -- and that's fine. And if their process stops at deism, I don't really care very much. People who believe in deism aren't going to inflict much harm on themselves or others trying to appease their entirely non- interventionist God.
I'm just saying: If you've stopped at deism -- if you believe in a God who's out there somewhere, or who was out there somewhere at one time, but whose existence is 100% indistinguishable from his/ her/ its non-existence... then I'd like to encourage you to look at whether that belief really makes sense. And I'd like to encourage you to take that final step, that leap of non-faith. Come on in. The water's fine.