How would you describe the relationship between "spirituality" and "rationality" in religion? To use an exteme but specific example, the aztecs would sacrifice children to Tlaloc in order to summon rains. This is clearly not a "rational" activity, rooted in magical thinking, but at the same time religion cannot be described as being "irrational" without being reductive. People do things for a reason, and the way we do those things is ultimately informed by our material conditions. So how does the study of spirituality explain this?
Well the eternal question is how, right? To use your example, yeah sacrificing people to appease Tlaloc was irrational. But, it likely served as a meaningful show of force for the thriving and expansive Aztec triple alliance. Generally speaking Aztec ritual murder was not a "sacrifice" in the sense of a Greek offering to the Gods. It was the execution of prisoners of war. It served a social purpose similar to the similarly-brutal Roman practice of decimation. The Aztecs just had a special building and special knives for it. Which makes sense. It's a special activity.
