I am familiar with Sutras (and Suttas), but not much with the Tantras. In what way are both different from each other?
1. Are Tantras exclusively like training manuals of various Yogic and ritual practices unlike Sutras which contain both practices as well as metaphysical, moral and general discussion of Buddhism?
2. Tantras are meant to be secret where as Sutras are meant to be open?
There are basically two theories about the origin of tantras from two perspectives : historical and mythical. The historical origin of Tantras point to Hinduism or proto-Hindu-Shamanism with a gradual adoption of Tantric methods into Buddhism by some monks and lay Buddhists to win over rival religions. This was a common tactic in the historical times for one religion to usurp another religion's traditions and color them in its own philosophy to win over new converts from the other religion. Hinduism did the same with Buddhism by calling Buddha as an Avatar of Vishnu who had come to delude the demons away from holy Vedas.
The second theory about origin of tantras is of course that it was composed by other beings (Buddhas, Dharma-protectors, Vajrasattvas etc) and the tantras literally drop from the sky or was revealed in visions. Frankly, considering the logic in elaborate historical analysis about the origins of Tantra from pre-Vedic shamanism, it seems pretty difficult to believe that this myth is in fact correct.
How do you Vajrayanists reconcile with this fact?


