* * *Steven's Opening Essay
Let theism be the belief that a god exists, atheism the belief that no gods exist, polytheism the belief that more than one god exists and monotheism the belief that only one god exists. 'Classical' polytheism asseverates the reality of gods.
Which strategy I use to establish polytheism largely depends upon my interlocutor. If she’s atheist, I’ll argue that a god exists. However, my opponent already concedes this. What we disagree on is how many gods exist: he believes only one god exists, namely, God. Theoretically, I could try and establish polytheism by arguing that some deity other than God exists. But, I don’t think he does, and will therefore take a step towards polytheism—indeed the only step I can take in this debate—by arguing that God doesn’t exist.
I'll present a moral argument against God by showing that his existence would eliminate a moral duty very dear to our hearts. The argument is based on the innovative work of atheist philosopher Stephen Maitzen. 
What do I mean by ‘God’? More or less, just the philosophical conception of the Abrahamic deity: it’d be (minimally) omnipotent, omniscient and morally perfect. The existence of this God is fundamental to the great monotheistic faiths because if there is no omnipotent, omniscient and morally perfect being, then a fortiori, there’s no omnipotent, omniscient and morally perfect being with a Trinitarian nature, that commissioned anyone as its prophet or that inspired any sacred texts. Consequently, the success of my argument would have far reaching implications. But, atheism needn’t be one of them, which is why this is a step in polytheism’s direction.
Almost all of the argumentation advanced in God’s favor provides just as much evidence for some one or more other deity. E.g. Intelligent design arguments would merely evince the existence of an intelligent designer, a description any god that designed the universe would meet. Even religious experiences believed to have been of God can be seen—in light of God’s non-existence—as mistaken perceptions of another deity, much like when in the setting sun, a distant propane tank is mistaken for a cow.
So, how does the argument work?
II. The Argument
1. If God exists, then any child that suffers will ultimately benefit from it. [Premise]
2. If any child that suffers will ultimately benefit from it, then no one ought to proactively prevent any child from suffering. [Premise]
3. But, someone ought to proactively prevent a child from suffering. [Premise]
4. Therefore, some child that suffers will ultimately fail to benefit from it. [(2), (3) M.T.]
5. Therefore, God doesn't exist. [(1), (4) M.T.]
Proactive prevention is stopping an event from occurring, reactive prevention is stopping an event from continuing.
This argument is deductively valid, meaning if its three premises [(1)-(3)] are true, then its conclusions [(4) & (5)] have to be true. To show that God doesn't exit then, I need only show that my premises are true. But, are they? Let’s investigate them one by one.
Premise (1): If God exists, then any child that suffers will ultimately benefit from it.
Simply put, the first premise is true because allowing a child to suffer purely for someone else’s sake (or for no one’s at all) is child abuse and God would not abuse children. It would harm the child's well-being and likely inflict psychological damage as the child comes to grips with the frightening and cruel reality of having to agonize for no good reason. As Kant recognized, it’s wrong to use any person merely as a means to an end. If premise (1) is false, then God—who’d be morally perfect—would use a child like a tool without any personal dignity, and not just for inconsequential purposes, but in such a way that the child suffers. If someone can simultaneously be morally perfect and a child abuser, I’m not sure what’s left for nonsense to refer to. I feel that most people will be comfortable endorsing (1). 
However, what of more inquisitive minds that wish to investigate deeper? They’ll want to look for counter-examples, and see whether God even could insure that every child that suffers ultimately benefits from it.
For instance, retributive punishment might be proposed as a counter-example: a morally permissible instance of allowing a child to suffer without ultimately benefiting from it. (If it was rehabilitative punishment, the child would obviously ultimately benefit) But, I submit that retributive punishment for a child is gravely questionable, and doing so by allowing it to suffer is morally forbidden. Suffering does not refer to the discomfort of sitting in a corner for time-out, having your games taken away for a weekend or even getting spanked: it's an agonizing level of pain that no child should be subjected to unless it ultimately benefited from it.
But, let’s suppose someone is not convinced and maintains that retributive punishment is a counter-example. It’s really no trouble at all to restrict the suffering we’re talking about to those instances of undeserved and involuntary suffering. Retributive punishment would then no longer be a counter-example, it’d be entirely irrelevant.
Or perhaps my Catholic opponent—or hypothetical non-Catholic Christian, Jewish or even Muslim interlocutor—believes that contrary to premise (1), if God exists some child will fail to ultimately benefit from her suffering, because her suffering will be that from hell, and no one ultimately benefits from the pains of hell. But, this move would be inappropriate because its acceptability assumes that hell and sin would exist if God did, and that'd only be established via special revelation from God. In other words, you can't buy this response unless you already believe in God, something that can't fairly be expected of me. But, then it also wouldn't be fair to expect me to find the reponse convincing. However, even if this response wasn't question-begging, I don't think my opponent would be warranted in saying who resides in hell (or will come to in the future), meaning I doubt he could reasonably say that if God exists some children will suffer in hell. For all he knows, it may only be adults that wind up in hell.
The interest in whether God could accomplish such a feat will most likely arise from worries over free-will: couldn’t humans freely interrupt God’s intention and prevent a child from ultimately benefiting from its suffering? But, the question is uninteresting since even if we answered yes to it, it would still be true that humans could just as well fail to freely disrupt God’s intentions. Whether free-will is compatible with determinism—in which case God could just determine people to not interrupt his goal—or not—in which case God could foresee and make real those circumstances in which every agent fails to freely interrupt his goal—God could still insure that any child that suffers, ultimately gains from it.
There is very good reason for thinking that premise (1) is true.
Premise (2): If any child that suffers will ultimately benefit from it, then no one ought to proactively prevent any child from suffering.
The second premise is true because a child can’t ultimately benefit from its suffering unless it suffers in the first place, and it can’t suffer in the first place if it is proactively prevented from doing so. Thus, if a child will in fact ultimately benefit from its suffering (as (2) stipulates), then it will not be proactively prevented from suffering. In fact, it’s impossible for a child to ultimately benefit from its suffering if it’s proactively prevented from that suffering, for then the child will and will not be proactively prevented from suffering. Premise (2) is true on pain of denying the law of non-contradiction.
Since ought implies can, and one cannot proactively prevent a child’s suffering if it will ultimately benefit from it, then no one ought to, just as premise (2) asserts.
Furthermore, one could only be morally obliged to proactively prevent a child from suffering if allowing the child to suffer would be wrong. But, if there really was a greater good made available to every child through suffering, it would not be wrong to allow any of them to suffer for the sake of that greater good. Any instance of their suffering would just be like when we allow a child to feel the pain from a needle so they might ultimately benefit from a vaccine or surgery.
Premise (2) is rationally indubitable.
Premise (3): But, someone ought to proactively prevent a child from suffering.
Our final premise is definitely true because someone should proactively prevent children from being sold into prostitution, from being mercilessly beaten to within inches of their life, or from being abandoned to a lonely and agonizing death like starvation.
The only response denying (3) deserves is the incredulous stare. 
I’ve presented a validly deductive argument against God’s existence with just three premises. Its first premise is true unless God would abuse children. Its second premise is true unless the law of non-contradiction is false. And its final premise is true unless things like child prostitution aren’t wrong. Denying any of these premises is absurd.
Unfortunately then, our conclusions follow and not every child will ultimately benefit from the suffering it endures. As heart-breaking as this reality is, it’s actually why we fight so hard for children, a fight we otherwise wouldn’t need to engage in.
This limits my opponent's response to two possibilities. First, he may concede that the premises are true, and therefore that God does not exist. As I mentioned earlier, this would not mean becoming an atheist, in fact I would hope to convince him of polytheism if he did take this route. Secondly, he may just find the conclusion too implausible to buy. In order for this to be a rational response, the premises of the arguments that convince my opponent of God's existence must be more plausibly true than my premises. But, as I've argued, it's absurd to deny any of my premises. If you must embrace absurdity to believe in God, then it doesn't seem reasonable to believe in God. I can't imagine his premises being more plausible than mine, and thus have to say that if he really does have excellent reasons for believing in God, they'll collide with my argument resulting in a stale-mate. In other words, while he may not reject God's existence as a result of this argument, it doesn't seem that he should affirm God's existence either, since the probative force of our arguments will cancel each other out. This would still leave him open to a case for polytheism.
In the final analysis, the argument seems to be such that it should convince a reasonable and reflective Judeo-Christian monotheist to change their mind about God's existence.
: Maitzen, Stephen. “Ordinary Morality Implies Atheism.” European Journal for Philosophy of Religion 1:2 (2009): 107-126.
: Heavy-weight Marylin McCord Adams recognizes this in her Horrendous Evils and the Goodness of God. Ithaca, NY: Cornell UP, 1999. She’s well known for arguing that God would defeat the horrendous evils (roughly equivalent to the child-suffering I have in mind) which people endure. Defeating an evil amounts to integrating it into the person’s life so that the evil indispensably contributes to the person’s overall well-being. E.g. Think of evils that people have experienced but don’t regret having done so because they gained something valuable from that experience.
: Lewis explains that the incredulous stare is "a gesture" you make towards a proposed claim that you yourself couldn't believe in your "least philosophical and most commonsesical moments." Cf. Lewis, David K. On the Plurality of Worlds. Oxford, UK: B. Blackwell, 1986. p. 135.