TAPAS. The Sanskrit term tapas, from tap ("heat"), was in ancient India an expression of cosmic energy residing in heat, fervor, and ardor. Through anthropocosmic correspondences established in early Vedic sacrificial traditions tapas became one of the key concepts of South Asian religions and the accepted term in Sanskrit and other Indic languages for ascetic power, especially a severely disciplined self-mortification that produces both personal and cosmic results.

A wide range of religious expressions concerning tapas appears already in the Ṛgveda. The gods Agni, the sacrificial fire, and Sūrya, the sun, both possess heat inherently, whereas tapas is generated within the warrior deity Indra and his weapons as a concomitant of heroic fury in battle. Indra's heated rage may be connected to certain proto-Indo-European warrior-cult phenomena; Ṛgvedic references to ascetics who handle fire, as well as other references to sweating as an initiatory technique, may be connected...