Exactly. But atheists should be open to the possibility that there might be a God.
Kinda sorta. We should be open to a god that fits the facts at hand (i.e. that God is indistinguishable in every way we can measure from a god that doesn't exist) and consider how god-claims even ended up developing and coming forward. We don't need to be open to any god that comes with testable claims that we can determine are false.
And in practical terms, "being open to something" only translates into real changes in action when the reach a reasonable level of likelihood. Am I open to the possibility that a tiger has gotten loose from the zoo? Sure - things like that have happened before. Am I going to run instead of walk from my house to my car to minimize the time I could be pounced on by a tiger? No.
That is my objection to materialism; the assumption that it *is* true, and often condemning others who reject it.
I think that calling out materialism is generally a red herring. Acceptance versus rejection of materialism or the supernatural really has no bearing on the truth or falsehood of a claim; all that it should affect is whether a person has one category to put stuff in or two.
What I see happening a lot is that credulous people will label the things they want to believe in but can't justify "supernatural," and then claim that this exempts them from needing a rational justification.
If the issue really was just materalism vs. supernatural dualism, here's how the discussion would go:
- dualist: "I have good reason to believe that X, which I consider supernatural, exists."
- materialist: "I agree that we have good reason to believe that X exists, but I consider it to be material."
Any time we have a disagreement about whether something exists at all, it's about either standards of evidence or the facts at hand. It isn't about materialism vs. dualism.