Seems to me that Gnosticism is a more Buddhist approach to Christianity (unless I'm severely misinformed), so you'd think everyone would be more relaxed about their religion.
But since people tend to congregate, it would eventually turn into an organized religion telling you what to believe and not to believe...and therefore not much different than today.
Very different, Gnostics (and every other Esoteric tradition) doesn't believe in conversion, evangelism, or hierarchical ruler ship in religion. Gnostics never claim that they "have the only truth", but rather claim "the truth is within you".
Impossible to tell. The west almost certainly would not be as powerful as it is today as the Church is all that held the West together and kept much important information alive. I also doubt that Gnostic's would be much of a power, what with the insular nature of their beliefs.
I await the day that religion will no longer be a topic of discussion in any society. Where people are allowed to believe whatever they chose and are not judged for their beliefs but by their actions.
What would the world look like today if Gnosticism and not Christianity came to promi
