A simple thought experiment to show that God belief is inherited and acquired second hand, from family and culture, is to imagine an atheist on an island by himself, and on a totally different island far, far away a Christian.
With nothing–not a holy religious book or anything outside influence, except for the wind in their hair and the sand beneath their feet, and a few coconuts to survive on, after thirty years, assuming their insanity holds up (excluding the volleyball with a face on it called Wilson ala Tom Hanks) do you think the Christian will remain a Christian?
But it’s not out of the realm of possibility to imagine him throwing up his arms and relinquishing his faith either. In fact, God’s thirty year long silence would seem as if God had ceased to hear his pleas for help altogether, or likewise, it would seem as if there was never any God to hear those please to begin with. It’s not hard to imagine that after such a long time the Christian would feel resentment toward God for turning a cold shoulder and leaving him there all alone to wither away on that distant shore forlorn. That is to say, his doubts would be steadily accumulating for thirty long years. Do you think his faith could survive the build up of thirty years of massive, soul crippling, doubt? Possibly, but it doesn’t seem very likely.
Now to juxtapose this example with the nonbeliever, we must ask ourselves, what are the odds of the atheist, mind you still perfectly sane (apart from his version of Wilson carved into a coconut), spontaneously creating an entire religion by himself and worshiping the same exact God as the rest of the planet, with more or less the same tenets and rituals, that he doesn’t even know about (not having been raised religious)? Not very likely, I’d assume.
In fact, I think it would be safe to assume the atheist would have no reason to suddenly develop belief in a god at all. Both developed imaginary friends, but they never had any incentive to worship their Wilson companions as an island deity. And if they had, it wouldn’t be a real religion. And what’s more, we could prove it.
Well, that’s how I see all world religions now that I am an atheist. They all appear invented–mere figments of mankind’s collective imagination. What’s more, it takes the tradition of family and culture, all locked into rigid customs of ritual, to preserve and transmit these beliefs. Without that framework, I feel, God belief would not survive a single generation.