The arguments for God in vogue among the Christian apologists that I listen to have a curious flaw. I’m surprised when they take little notice of this.
Consider the following popular arguments and see if you can find the common feature. In-depth discussions of these arguments deserve their own posts, but I’ve added brief (and incomplete) summaries to remind you what these arguments claim.
Popular Christian Apologetics

• Cosmological Argument: “Someone had to get everything started, therefore God”
• Moral Argument: “Objective morals exist, and who but God could create them?”
• Transcendental Argument: “What grounds logic? God does.”
• Ontological Argument: “If ‘God’ is the greatest possible being that we can imagine, and a being existing is greater than being imaginary, then this greatest being must exist.”
• Design Argument: “Just look around you and you’ll see the marvelously complex design of a Designer.”
• Fine Tuning Argument: “The constants that define the universe are fine-tuned for life, therefore God.”
• Argument from Incredulity: “It’s all just so … so incredibly complex! Therefore, God.”

What’s the common feature? It’s that these are all deist arguments. If I bought into any one of them, I’d only be agreeing that some deity (or deities) created the universe. But which one? These arguments are as good for Islam or Shintoism as Christianity and Judaism.
(This reminds me of the famous Sidney Harris cartoon with the punch line “I think you should be more explicit here in step 2.”)
And yet the apologists are often unaware of the problem. They finish their deist argument with a “Ta-dah!” and a sweep of the hand and think that they’ve made a sale, but they’ve got a long way to go to convince me that their particular deity is the real one and it’s actually all those other ones that are mere human inventions.
Maybe they count on ambiguity to help. They conclude that God created everything and—whaddya know?—their god is named “God.” I’ve written before about this odd confusion of names. It’s like a cat named “Cat.”
One noteworthy exception is John Warwick Montgomery, an apologist from an earlier generation. He takes the opposite approach and first uses the New Testament to argue the resurrection of Jesus. From there, he tries to build the rest of the Christian worldview. This approach is no more convincing, but at least it avoids this problem with deist arguments.
How Can We Access the Supernatural?
If we explain the world in a Christian way, God is active in our natural world, and we can see his hand in Nature. This runs into a problem that (IMO) is for Christians at least as big a problem as the Problem of Evil: the Problem of Divine Hiddenness. If God enters into our world and is eager for a relationship, why the mystery? Why make things so difficult? Why make our world look exactly like a world without a god?
And if we imagine the opposite, that God isn’t particularly eager for a relationship or isn’t motivated to provide compelling evidence that he exists, then we’re back in the deist camp. We have a deity who indeed exists, but we’re on our own to show that he exists anywhere but in our minds. And if the deity hasn’t provided a conduit between the Natural and the Supernatural, why imagine that natural techniques (prayer, meditation, or logic, say) could prove the existence of the supernatural? If God is just sitting there and not helping us out, how can we show that he exists?
Christians sometimes argue that science is incapable of detecting the supernatural. But keep in mind that the boundary of “natural” expands with time. Seeing through opaque objects was supernatural before X-rays, for example. And even if science can’t detect supernatural beings, what makes those Christians imagine that they can?
A couple of analogies come to mind. Imagine using integers (1, 2, 3, …) with addition and subtraction and trying to creating anything but more integers. You couldn’t reach 7.65, the square root of 2, or pi, for example. Or, imagine a two-dimensional Flatlander trying to prove the existence of three-dimensional space. Sure, he can imagine it, but that’s hardly a proof.
It seems to me that our pointing to evidence of the supernatural with a deist argument is like creating all real numbers using addition and subtraction on integers, or a Flatlander proving the existence of 3-space. Sure, we can imagine something more, but that’s no proof and not particularly compelling evidence.

Glendower: I can call spirits from the vasty deep.
Hotspur: Why, so can I, or so can any man;
But will they come when you do call for them?  
— William Shakespeare, Henry IV, Part I, act III, scene i

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