*1. "But now, I ask you, how can such an existential account of facts of mental history decide in one way or another upon their spiritual significance?"*
What does James mean by spiritual significance? Also, spiritual significance to whom?
*2. "By their fruits ye shall know them, not by their roots."*
This seems to me to sum up James' position on how to determine value of religious ideas. But what makes a fruit desirable or not? How do we tell between good and bad (or useful or non-useful) fruits? Religion is one of the main things that claims to offer judgments on whether fruits themselves are good or bad.
*3. "In the natural sciences and industrial arts it never occurs to any one to try to refute opinions by showing up their author's neurotic constitution. Opinions here are invariably tested by logic and by experiment, no matter what may be their author's neurological type. It should be no otherwise with religious opinions...Immediate luminousness, in short, philosophical reasonableness, and moral helpfulness are the only available criteria."*
What logic and experiment can test religious opinions? Also, what are we testing religious opinions for? Truth seems out. Perhaps James would say usefulness? Then, it seems desirable to outline a set of desirable fruits. See (2).
What does he mean by "immediate luminousness" or "philosophical reasonableness"?
--Beth