(Q) said:
Yes but would one recognise God as God even if he did present himself?
That should be simplier to deduce than what you'll have for lunch.
You commit yourself to a religion founded by a single man who claimed to have spoken to an angel, who was a messenger from god, yet you question whether all mankind combined wouldn't recognise god if he revealed himself?
Of course it could; that was the conclusion of a lot of people who saw it too.
Yes, and they were such a fortunate group of people, out there alone in the desert with Muhammand, considering the rest of the world in the line of site of the moon had completely missed the event!
One would've expected the entire planet to have converted to Islam the very next day.