What would change?

[Penumbra]

Concur. The hypothetical gets too far fetched when you say "irrefutably." If for some reason I became personally convinced there was no god of any sort, I think that under some circumstances I might at least seriously consider suicide and take my wedding vows less seriously. (Streets, however, are a most uncomfortable place to fornicate, itself an activity that does not blend well with dodging cars.) Though I doubt I would become a sociopath or career criminal, believing that "It All Just Happened" would certainly cut the foundations out from under whatever moral code you might describe me as living by. "Evolutionarily adaptive" is not much of a rallying cry.

Why would you take your wedding vows less seriously? If you are in love, then what does it matter if there is a god or not to be faithful to your wife?

However, you're asking what I, or my fellow believers, would do if (it were possible) I gained a proof of God's non-existence. I like to think through the logical consequences of a belief, and here are two conclusions that flow from atheism:
1. Life is meaningless
2. There is no objective right and wrong

I concluded that those two points were true when I was still a theist. I think those conclusions flow from certain observations of life in general, not just from some specific philosophy/belief/lackthereof like theism or atheism. People can form a subjective meaning for their life if they choose to and are able, but I don't see any possibility of objective life meaning in either theology or atheist philosophy. It just is what you make it and nothing more. I don't see how the addition of a deity adds meaning to life.

So I guess my answer to the OP's question would be a bit less theoretical considering that I'll say what I went through when concluding that there are probably no gods instead of what I would do if I concluded that.

When I was a theist, I already concluded those two points, and was depressed. Upon deconversion from theism, nothing changed. I know, kind of anti-climactic, but there's my answer. No significant change.

-Lyn

 

[Sphinx777]

Agent Smith: Why, Mr. Anderson? Why do you do it? Why get up? Why keep fighting? Do you believe you're fighting for sombething? For more that your survival? Can you tell me what it is? Do you even know? Is it freedom? Or truth? Perhaps peace? Yes? No? Could it be for love? Illusions, Mr. Anderson. Vagaries of perception. The temporary constructs of a feeble human intellect trying desperately to justify an existence that is without meaning or purpose. And all of them as artificial as the Matrix itself, although only a human mind could invent something as insipid as love. You must be able to see it, Mr. Anderson. You must know it by now. You can't win. It's pointless to keep fighting. Why, Mr. Anderson? Why? Why do you persist?


Are you the One?

 

[Penumbra]

Agent Smith: Why, Mr. Anderson? Why do you do it? Why get up? Why keep fighting? Do you believe you're fighting for sombething? For more that your survival? Can you tell me what it is? Do you even know? Is it freedom? Or truth? Perhaps peace? Yes? No? Could it be for love? Illusions, Mr. Anderson. Vagaries of perception. The temporary constructs of a feeble human intellect trying desperately to justify an existence that is without meaning or purpose. And all of them as artificial as the Matrix itself, although only a human mind could invent something as insipid as love. You must be able to see it, Mr. Anderson. You must know it by now. You can't win. It's pointless to keep fighting. Why, Mr. Anderson? Why? Why do you persist?


Are you the One?

I love his monologues. Such a cool villain.

 

[Suggestion Box]

ok in answer to the OP (sorry haven't read any other posts), i would keep doing exactly what I'm doing now. the advice in the gospel is good advice whether or not you believe in God... its a satisfying lifestyle.