Kaydrub Norzang-gyatso, in "A Lamp for Clarifying Mahamudra to Establish the Single Intention of the Kagyu and Gelug Traditions", has explained that those for whom everything happens at once are persons who have trained extensively through stages either in previous lives or earlier in this life. As a result, meditation on the nonconceptual state of the mind, without need to rely on any further meditation on penetrating vital points of the vajra-body, alone causes clear light mind to manifest so that everything happens at once. Such meditation does this by acting as a circumstance for triggering the ripening of potentials built up from previous practice with energy-winds and so forth, so that they automatically enter, abide and dissolve in the central energy-channel. If a practitioner has not built up these potentials, then no matter how intensively he or she may focus in a nonconceptual state of mind, this person is unable to manifest clear light mind or pure awareness. They lack sufficient causes.