“A journey to the depths of the mind involves great personal risks because we may not be able to endure what we find there. That is why all religions have insisted that the mystical journey can only be undertaken under the guidance of an expert, who can monitor the experience, guide the novice past the perilous places and make sure that he is not exceeding his strength, like poor Ben Azzai, who died, and Ben Zoma, who went mad. All mystics stress the need for intelligence and mental stability.”
