The question is what exists capable of filling that gap. Just answering "paganism" won't suffice. The population itself looks for a state-approved religion and Catholicism/variants will fill that gap.
There is a priest on each village, there is a top-down organization making sure that all rites are properly executed. Where is the European answer to that? I don't think none of the rulers around here have the will nor motivation to move away from desert tribe religions.
To fill that gap, to provide the framework necessary for a truly free and self-sovergn society, surely must require:
1) Logic / Reason
2) Empirical / Practical Application and Assessment
3) Consistency of Principles and Application
4) Honest Communication
5) Acknowledgement of Error and Implementation of Correction
Not necessarily in that order and I’m probably missing something.
One major reason Christianity results in preferable and more fruitful and content societies is because the moral & ethical framework is generally consistent.
