Virtually no commentators on mysticism deny that it grows from roots in vivid religious experiences. Usually you do not become a mystic by studying academically (though studying academically is certainly an experience, and now and then such study has mediated living encounters with ultimate reality). Usually you start on the path into mysticism through an experience of transport -- being taken out of yourself through a response to beauty or pain. The experience is so good, so distinctive, that it turns you at least half-way around, "converts" you at least partially to the proposition that reality is much more than what you thought it was before this happened to you.
Charmed and challenged, you set out to learn more about what happened to you and, if you are fortunate, you find guidance into regular, habitual disciplines calculated to make constant your dealings with the reality that is much more than what you appreciated initially. These disciplines are important, but it is axiomatic in the lives of the mystics that experience got them going and made them persevere. Thus after witnessing sickness, old age, and death, the Buddha was so moved that he left his cushy life in the palace and determined to gain an enlightenment that might solve the problem of suffering. The parallel for Jesus was probably his compound experience of being baptized by John the Baptist and led into the desert to be tempted by Satan. After this, he