This is a dumb question because it's a loaded question insofar as it appears to ask for an objective answer to a question that can only be answered perspectivally. Most of the responses in this thread have answered from an external perspective - that is, as religious outsiders opining on the (obviously) ludicrous phenomenon that some people in the world subscribe to authoritative religions. However, from the internal perspective of a Christian, or most followers of other theistic religions, religion, that is true religion, obviously derives its authority from the fact that it is true. But, of course, if the question "from where does religion derive it's [sic] authority?" presupposes the answer is NOT from God, that is, it presupposes religion's falsity, then it is asking for an answer exclusively from the people who have the least first-hand knowledge of the topic. A religious believer is like a Copernican. If you asked Copernicus "from where does heliocentrism derive its authority?" he would struggle for an answer - for its "authority" derives from its truthfulness. He could show you EVIDENCE in support of its truthfulness, but it's odd to speak of this evidence as being what heliocentrism "derives" its authority from, as if its truthfulness is not an independent fact. It is the anti-copernicans who can spout myriad answers to the question "from where does heliocentrism derives its authority?": from Copernicus, from the stupidity of man, from the psychological desire to believe what is novel, from aliens which jiggle with our brains. Because the anti-copernicans believe heliocentrism is false, they can give you no end of answers; the Copernican can give only one: from its truthfulness. The question of religious authority is similar. The believer can give only one answer to the question "from where does religion derive its authority?": from its truthfulness. It's the non-religious who are able to pile up answers. But if you want those answers, the most honest way to ask the question is, "From where do you think religion derives its authority given that it is false."