Continuing on with Mackie’s “Miracle of Theism”, we get to a couple of the few actual arguments against God’s existence. I rather enjoyed this one, both for the content, and for the novelty of seeing any attempt to offer a reason to reject belief in God.
Unfortunately, these were single points rather than developed arguments, and not terribly strong in any case.
Mackie begins with the suggestion that theists need to offer a reason why God made just this universe, rather than some other one. And the first thing to be said here is that this assumes that God made only one universe. Many theists have suggested otherwise.
Second is the fact that theists have given reasons. If the creation of life is an important consideration for God, then there is a very limited number of universes that would be made. Of course, this doesn’t answer the question of why, precisely, this universe over other life-supporting universes, but this isn’t much of an objection.
Really, I can think of no theory that explains its content within such an astronomically high degree of accuracy as Mackie seems to be demanding (once one understands the limits life puts on a universe). And, if this were a reason to dismiss theism, it is certainly a reason to dismiss the far more vague answer given by non-theists.
His second reason is more popular, but I find it less persuasive. He claims that a mind without a physical body (i.e. God) is intrinsically very improbable on the grounds that we have no experience with such a thing. I see two major flaws with this.
First is the fact that this confuses absence of evidence for evidence of absence. I don’t know of anyone who argues that the multiverse is intrinsically improbable, for instance, on the grounds that we have no experience with it.
And I’m not convinced that we have no experience with minds as separate from bodies in the first place. Not only do the overwhelming majority of people in the world claim to have had such experiences (that is, most people are theists), but this seems to presume a materialist view of the human mind (which is fraught with problems–we can’t even say that our minds are purely physical). Certainly, it assumes that all the other arguments for God fail, rather than simply being inconclusive (or, as I would claim, good arguments).
Mackie even argues against some of them by suggesting that we remain neutral on them. As such, he can’t base an argument on the idea that they all fail.
So, as an atheist, Mackie is free to assume these things, but to base an argument for atheism on the idea that minds are always physical is simply circular reasoning.