6 ideas
The origin of a religious state, whether neurotic, pathological or chemical, says nothing about its value. Rejecting a belief because its source is a disordered nervous system is 'medical materialism', and it would discredit genius and science too. Religious states must be judged by immediate luminousness, philosophical reasonableness and moral helpfulness.
Healthy-minded people are 'once-born': they refuse to dwell on evil and find the world good at first sight. Sick souls are 'twice-born': they feel evil as the essence of existence and can only reach peace through a second birth that passes through despair. James argues the sick soul's view is more complete, because evil is a genuine part of reality.
Conversion is the process by which a self that was divided, consciously wrong and unhappy becomes unified, consciously right and happy. It happens when religious ideas that were peripheral in consciousness move to the 'hot centre' of personal energy. The shift is often prepared by subconscious incubation, so it can feel sudden and given from outside, especially after the person gives up the effort of willing it.
James identifies four marks of mystical states. They are ineffable, meaning they cannot be adequately put into words. They are noetic, meaning they feel like knowledge. They are also transient, lasting briefly, and passive, felt as happening to the subject rather than done by them.
James inhaled nitrous oxide and felt a deep conviction of truth in which opposites merged into a single reconciling unity. From this he concluded that ordinary waking consciousness is only one type among others, separated from them by the 'filmiest of screens'. No account of the universe can be final if it disregards those other forms of consciousness.
Mystical states that are well developed carry legitimate authority for the people who have them. They do not bind outsiders to accept their revelations uncritically. Their existence still breaks the claim of rationalistic consciousness to be the only authority, because they show that other orders of truth are possible.