Nonsense. Here’s your test:

“Hey God, if you’re there, show yourself to me.”

If he does, there’s your proof. (Of course, accounting for fraud, and so forth.)

Proof of God’s nonexistence is of course a different matter, but that’s the old “prove a negative” problem. Unfortunately, given the sparseness of evidence like the above, that’s about all we have to work with.

Well, that would prove something had existed in the past, its nature depending on the content of the message, but even it had said “I exist always” we wouldn’t have to believe it.

But you know if we let imaginations run wild, the Big Dude could just open the sky like drapes and shout “Here I am!”. Now such an event is not in my ontology, but there are millions of people who expect that exact event to happen… “Left Behind” club. I, as a secular modernist, have spent part of my life trying to view that group as something other than superstitious savages.

A hidden message in pi or e (a la Carl Sagan’s Contact) would do it, at least to a very high probability. On the other hand, there is no conceivable test to prove the *non*existence of God, since if God does exist he could always spoil the results of any test in order to hide himself.

Many do convert due to some kind of ‘spiritual experience’, though. John C. Wright a notable recent example http://mostlyfiction.com/authorqa/wright.htm

McClain:
Identifying atheism/agnosticism with teen rebellion is breathtakingly patronising. As it happens, I was raised atheist, and never identified as anything else, though it took a little longer for my worldview to become fully naturalistic. YMMV

I agree with you Will that ‘atheist’ does not have two distinct meanings. Posner is wrong about that. It’s just that I think that there are two kinds of atheists.

The idea of exploring every nook and cranny of the universe should be fine, even if it would be really difficult to marshal the resources. The billions of explorer spaceships need not have infinite fuel or take infinite time (unless the universe is infinite, in which case Bob is in trouble).

As for a “god detection” machine, there’s no reason to believe that such a machine can be built.

I don’t necessarily like the verification criterion of meaning, but I think that’s how one of its adherents might reply.

The distinction clarifies two different types of atheism. Weak vs. strong, the way I’m stating it, is about whether someone lacks belief in god or positively believes in god’s nonexistence; the distinction deals with belief about existence simpliciter, not belief about the possibility of existence.

I think it’s a useful distinction for a couple of reasons. First, someone who has never thought about the supernatural in any capacity is, I would claim, an atheist because they lack belief in god’s existence. Someone who has given the issue deep thought and intellectually decided that god doesn’t exist has gone a step further. They have a belief that the “weak” atheist doesn’t, namely: “God doesn’t exist.” The second very similar reason is that I find it helpful to distinguish between agnostics (who lack the belief “god exists”) and atheists who outright reject god.

I think that the distinction really does capture two different worldviews, even though I don’t often make it in practice. Usually, I just say ‘atheist’ to mean anyone who lacks belief in god.