I was delighted to see that, even though he argues against theism, Mackie is not impressed by appeals to the anthropic principle. He sees clearly that, while it is not surprising that we don’t observe a universe that couldn’t have supported life, it is surprising that we do observe a universe that did.
A fairly common analogy goes as follows:
If one were to face a firing squad of fifty crack marksmen at point blank range, and all of them missed, it isn’t good enough to say “If I’d been shot, I wouldn’t be here to wonder why they all missed, so I shouldn’t wonder about that question now”.
This is the reason why those pressing the anthropic argument so often appeal to a multiverse. Of course, it must immediately be noted that a presumption of materialism is the only reason to consider the multiverse more likely than any other explanation. Outside of the fine-tuning itself, there is no evidence for it.
As such, Mackie dismisses the multiverse as a serious challenge to theism; he sees that it concedes the theists key points. (For those interested in that issue, I’ve written about it in the past.) Unfortunately, his alternative is no better. He insists that, the further one goes backward in time, explaining causes, the less there is to explain. Thus, he argues, something like a divine mind is far too much to deal with the little that would be left by the time one reaches the beginning of the universe.
Of course, this idea that there is less to explain as one moves into the past is more controversial than Mackie seems to think. In discussions over it, I’ve not seen it well defended. And it is definitely born out of a lack of appreciation for the actual numbers regarding the fine tuning; to call them astronomical is a wild understatement.
He also relies on the much less interesting, and much more obviously false, “what caused God” objection to insist that we stop our inquiry before getting to God. But, unlike most uses of this argument, he acknowledges the common response: that God is self explanatory in a way that the universe is not.
Unfortunately, he simply dismisses the idea without actually addressing the arguments in its favor. He references to his past discussion of the idea, which (as has already been noted) relied on an argumentum ad ignoratium fallacy and a shifting of goal posts in order to make its case.
Macke then closes with something that borders on the completely weird. That is, he suggests that the design argument requires a reason to think that matter is contingent.
As is always the case with Mackie, I’m not sure if he’s claiming that this is so, or merely throwing out a possibility. If the former, he needs to defend it; if the latter, he hasn’t actually rebutted the argument.
To be fair, he takes this idea from Kant and Hume. Still, that doesn’t make it a good argument. There are many clear reasons why matter is contingent–not the least of which is the origin of the universe that Mackie has just been discussing. Anything which is not contingent must necessarily exist eternally. The fact that matter has an origin precludes the possibility of it being non-contingent.
The most significant thing this shows, then, is how determined Mackie is to come up with reasons to dismiss theism. I don’t take back my earlier compliments of him–I do find him far more reasonable than most.
Still, if defending his materialism leads him to suggest that matter is logically necessary, and to constantly throw out possibilities that he does not defend, theism seems a far more plausible view.