William James

The problem how to discriminate between such messages and experiences
as were really divine miracles, and such others
as the demon in his malice was able to counterfeit …
has always been a difficult one to solve, needing all the sagacity
and experience of the best directors of conscience.
In the end it had come to our empiricist criterion:
By their fruits ye shall know them, not by their roots.

Primary Sources
The Principles of Psychology (2 vols)
Psychology: Briefer Course
The Varieties of Religious Experience A Study in Human Nature
The Will to Believe, and Other Essays in Popular Philosophy
Is Life Worth Living?
Human Immortality: Two Supposed Objections
Pragmatism; A New Name for Some Old Ways of Thinking
The Meaning of Truth: A Sequel to Pragmatism
A Pluralistic Universe
Memories and Studies
Some Problems in Philosophy: A Beginning of an Introduction to Philosophy
Essays in Radical Empiricism
Talks to Teachers on Psychology
On Some of Life's Ideals
Henry James, ed: The Letters of William James
R.B. Perry, ed: Collected Essays and Reviews

Secondary Sources
Bixler, J: Religion in the Philosophy of William James
Murphy, G and Ballou, R: William James on Psychical Research