Ratnakīrti (fl. c7-8th century), a Disciple of Dharmakīrti, wrote a work that further developed and refined the themes therein, entitled: 'Refutation of Other mindstreams' (Saṃtãnãntaradusana). He did not refute the tenets of the Saṃtãnãntarasiddhi but further developed the topic from an empirical one, that is, where there are manifold minds cognized by one's experience of others' Mental processes attributed through the perceived actions of other Sentient beings to an absolutist view, where there is only "one Mindstream" (ekacitta). Ratnakīrti's argument is that the valid cognition (pramāna) of another's Mindstream is an inference (anumāna), not a direct Perception (pratyakṣa). Moreover, Ratnakīrti introduced the two truths Doctrine as key to the nature of the discussion as inference is trafficking with illusiory universals (samanya), the proof of the mindstreams of others, whilst empirically valid in relative Truth (saṃvṛtisatya), does not hold ultimate metaphysical certainty in absolute Truth (paramārthasatya).