How to easily defeat any argument for God

[GrandizerII]

But if good is linked to wellbeing, then natural selection would've ensured that over time we (as a species, not individually) would be motivated enough to do what's good, even if in a tribalistic manner whereby we are selective of who we generally do good to.

Well, it's all in that "if," isn't it?

Natural selection selects for survival. Not truth, not goodness, not sophistication, not wonderfulness.

Yes, and as a means to ensure survival, natural selection has primed the human species to care about select others to one extent or another.

Selfish behavior is also conditioned if it ensures survival, true. Same with tribalism. Doesn't change the fact, though, that humans have learned to help each other out due mainly to the favorability of cooperation for continued survival. And this is good (helping people is a good thing after all). What's also good is that the species has thus a basic foundation upon which to further develop good. This is all contingent of course, but it's actual.

Not to anthropomorphize nature, but I think we tend to give millions of years of evolution + natural selection a lot less credit than it deserves for shaping the way we behave socially towards others, and we end up giving that credit to something that is instead deemed beyond nature. And that, to me, is unwarranted.

To say that what causes us to survive is necessarily good is to beg the question. I guess you could make an argument that "good" only and always means "that which helps us survive." But that's a big job.

Nah, I'm not taking up that job because I didn't say it like that.