At what point does one invoke notions of “mental illness” when engaging people making reference to “the Holy Spirit” telling them to do things…?

Conversely, at what point do scholars cease being interested in simply describing and understanding the people they study — working to reproduce their view of the world and “take them seriously,” as the old saying goes — and, instead, try to explain the reasons for their behavior…?

I think here of the work of the anthropologist Tanya Luhrmann and her effort to do participant observation among American evangelicals, to help correct biased readings of them and their beliefs, so as to demonstrate the implicit rationality to their worldview — such as when she writes (click the quote for the full article):

So, if that’s your goal as a scholar, then here’s a test case, from the recent news in Alabama:

Read the full article here.

So when do we need to take people seriously, understanding them on their own terms, as a form of dialogue between different viewpoints, and when are we free to make others comprehensible to us by minimizing their self-understandings and explaining them away as a product of some other mundane source — such as mental illness?

Simply put, what’s the difference between a prophet with a message and a vandal with a spray can? How do you draw the line — or do you?