| Preach to the choir|
|Crux of the matter|
|Speak of the devil|
|An act of faith|
Mysticism involves communion with the divine, either through esoteric knowledge or directly through revelation or meditation. Mystics come in all flavors, from the deeply sincere to the outright fraudulent.
While all mystics believe in something divine, most believers are not mystics. Many branches of Christianity, for instance, frown on this kind of direct communion, instead preferring "rational" argumentation and discovery of God through texts. However, Eastern Orthodox Christianity and, to a much lesser degree, Roman Catholicism somewhat employ mysticism in theological discourse.
One frequently finds that mystical experiences get induced by stressing the body (through hunger, thirst, sleep deprivation...), and/or by stressing the mind through isolation. All this can cause hallucinations, as can drugs that are used to induce mystical experience. There is every reason to suspect that mysticism - occurring across multiple cultures and across multiple religious traditions - is due to natural reactions in the brain from a materialist view.
- Compare: Gellman, Jerome (2018). "Mysticism". The Stanford Encyclopedia of Philosophy. Retrieved 10 September 2019. "'Mysticism' is best thought of as a constellation of distinctive practices, discourses, texts, institutions, traditions, and experiences aimed at human transformation, variously defined."
- See the Wikipedia article on Scholarly approaches to mysticism.