An atheist I know states “Since it is inconceivable that all religions are right, the most reasonable conclusion is that they are all wrong.” What would you say to him?
This argument can be parodied to death for those who have the patience. A simple example, though:
“Since it is inconceivable that all the interpretations of quantum mechanics are right, the most reasonable conclusion is that they are all wrong.”
Might work as a soundbite, but the logic itself is, well, rather poor.
Heck, even atheism itself can be “refuted” with this argument, as there is a variety of atheistic worldviews:
- Spiritualistic worldviews like Buddhism
- Non-naturalistic non-spiritualistic ones like Aristotelian naturalism
- Naturalistic, reductionistic atheism, etc.
All of these have to account for reality and explain it in some way without recourse to God. And since it is inconceivable that they are all true, then it is most reasonable to assume they are all false.
One might claim that the set of religions is bigger than the set of atheisms, and thus that makes the difference. Problem is, all things being equal, probability dictates that one of the options is more likely to be true in the larger set, which gives the advantage here to theism, not atheism.
Of course, one could claim that all things are not equal, but then your friend’s claim becomes pretty well irrelevant once you start going down that road, since you are addressing positions on their merits rather than making sweeping conclusions about many groups.