Religion has to be independent of reason because it exists to promulgate the continued power of the people who run it. If it was based on reason, then those authorities' authority would be subject to debate. "Don't eat carbs they're bad for you"... "well the science says otherwise." So religion generally sticks to the unfalsifiable domains. In the time of the Ancient Greeks the origin of electricity was unfalsifiable so lightning came from Zeus, winter came from Persephone, etc. As science expanded the domain of reason, religion retreated to the core unfalsifiables of meaning of life, origin of the universe, existence of the afterlife, etc.