While it is certain we would be hundreds of years behind without the onset of rationality and the breakdown in influence of the church, what would a hardcoded rationalist world be like? Is it a case where there is a need to balance with some semblance of spirituality? I suspect so, and given that the average person isn't going to conduct their own investigations into Truth (it's exhausting; I'm just glad it's behind me), that probably means adopting some mainstream tenet. I don't see a day when any of the major religions are abandoned. I'm particularly interested in the papal lineage as, according to the prophet who specialised in pontiffs, we're onto the second last one before the whole lot goes ka-blooie. Of course if the prophet is right then God is wrong (!!!) for His whole "No man may know the day" spiel. Unless of course the prophet was actually an angel or demon in disguise. Technicalities.