The only way to study religion from the outside is to isolate a part of life and call it religion, but like I said, that is to distort religion and disintegrate life.
Part of the reason I find atheists in RF amusing is that they think they can know God and religion the way one knows science, creatures and other men; that is, through the physical senses and with evidence that is compelling. But this is impossible. For God, being Absolute and Unconditioned, cannot be met in intellectual an encounter, be made the object discovered at the end of mere abstract reasoning, or the conclusion of an experimental process. For God is a mystery-experience, a presence, and a gift that must be received. God is not an intellectual problem, an idea, or object. The person who sulks in atheism because he has no sensible evidence, no solid facts for Gods existence, opens himself to the critique of being petulantly unreasonable in demanding what is impossible. He is an idolater: he has faith in man's self-sufficiency to the exclusion of faith in a transcendent ideal. True to his times, he is a non-knower of death and a mis-knower of evil.
Like I posted somewhere else:
Religion is superemotional, unifying the entire human experience. Authentic religion is part and parcel of human existence, not something that is acquired to embellish existence or to gloss over ignorance and insecurities. Even at its most primitive, religion is not one concern alongside others, not just another attribute alongside others like ethical, artistic, or scientific. It's a way of living. Authentic religion does not allow a person to be also religious. (Paul Tillich) To isolate a part of life and call it religion (or spiritual or "emotion") is to disintegrate life and distort religion. Even the very concept of religion effectively destroys the reality toward which it is supposed to point.