My rationale for disbelief

The following is taken from a Facebook wall-to-wall discussion I’m having (and he keeps deleting mine and his posts so I’ve decided to re-transcribe this here). This is in response to his question:

i would like to hear how you rationally decided that god could not exist

I’ll start with the assertion evolution is scientifically accepted (in that no scientific evidence has been put forth to cast doubt on the theory). So let’s think back to the emergence of the homo sapien species. We see social groups start to form, language emerge, and tool use develop. Now questions start arising (why does the sun rise, what happens when we die etc.). Elders of the tribe are generally respected in their tribe and they attempt to come up with reasonable explanations – the sun god makes the sun rise and set – so the tribe makes sacrifices to the sun god (or harvest god or whatever) in hopes that everything will continue merrily. Superstition spreads in some tribes, and their beliefs bind them. Those with tight beliefs and better morals (like the old don’t eat seafood, raw meat, etc. – things that would kill the ignorant) are better suited to survival and flourish (evolution directly favouring the tribes with the best beliefs of the time). As time passes different religions come and go, and eventually we see Christianity (and the other modern religions) emerge. Finally scientific methods start to dawn (17th century), and notions of the sun circling the Earth (because of god or whatever) are demonstrated to be false. As more and more is discovered, there becomes less and less need for people to hold onto the superstitions that allowed our species to persist this long.

So from my view, religion is a byproduct of evolution. With this in my mind, I see no reason that god needs to exist in any sense other than a mystical belief that our ancestors used to explain the unexplainable. Right now we still don’t completely understand the brain/mind, but I believe that we will gain a much greater perspective on that within our lifetimes.

From my view, it seems illogical to require a god still, beyond holding onto archaic traditions. And if you do believe in a god, which one(s)?

And to me its not that god doesn’t exist, but more that its very very very unlikely that he doesn’t (see Russel’s Teapot argument).