The interesting question for an evolutionary psychologist is whether, in the absence of proof one way or the other of the existence of any deity, there is any non-religious way in a Western context that we can release that part of our potential for good which, owing to a quirk of our culture or evolved nature, has hitherto needed the stimulus of religion to excite it.
An atheist might say that we were mistaken about the existence of God but fortunate in that our mistake caused us to discover beneficial ways of living and relating to each other. Religion having proved to be our "context of discovery", the question then remains: if we have been good without God, can we continue to be good knowing that we are without God? With the possible exception of those who are kind to others only on condition that they are rewarded with some kind of enormous metaphysical dog-biscuit when they die, I believe we can. Belief in God may have enabled us to discover human truths, but that does not imply that, if we abandon (or "dis-invent") God, we are obliged to abandon those truths too. Useful bathwater is useful bathwater, whether or not the baby exists.
Brighton, East Sussex