According to Sthiramati’s commentary (Triṃśikābhāṣya=Tbh) on the Triṃśikākārikā, contrary to our common sense, vikalpa and nirbhāsa occupy the same space. The aim of this paper is to consider this problem. Sthiramati made an important statement on this problem, as can be seen in the following quotation: tam ātmādinirbhāsaṃ rūpādinirbhāsaṃ ca tasmād vikalpād bahirbhūtam ivopādāyātmādyupacāro rūpādidharmopacāraś cānādikālikaḥ pravartate vināpi bāhyenātmanā dharmaiś ca. It is clear from this example that vikalpa and nirbhāsa occupy the same space. So far research on the term vikalpa (=abhūtaparikalpa) has been superficial. As Rishō Hotori acutely pointed out, vikalpa means mental material rather than the subject of cognition. However, strictly speaking, this view is unsatisfactory. We miss the point if we regard the meaning of the term vikalpa merely as mental material. What I wish to show in this paper is that the term vikalpa has two meanings, both subject of cognition and mental material.
