 Tsongkhapa conceives of tantra as a subset of the Mahāyāna, and to that extent all authentic Buddhist tantric activities are, necessarily, authentically altruistic. What differentiates tantric activity from other ordinary Mahāyāna activities is deity yoga (Tib. lha'i rnal 'byor), i.e., whether or not, from a first person perspective, the person is acting as a perfect, “divine” subject when engaging in (primarily ritual) behavior.