 Since it is vital to have a proper definition of a cognitive criterion, or a valid cognitive procedure and criterion of truth for philosophical enterprise, Jayarāśi analyses such definitions which were formulated within most important philosophical schools in India. The cognitive criteria whose various definitions are one by one examined are perception (pratyakṣa), inference (anumāna), presumption (arthāpatti), reasoning based on analogy (upamāna), negative proof based on absence (abhāva), equivalence (sambhāva), tradition (aitihya), and verbal or scriptural testimony (śabda, āgama). In terms of argumentative structure and nature, they all can be reduced to three: perception, inference and testimony. The philosophical schools which Jayarāśi most frequently refers to and criticises their definitions of the cognitive criteria are the Nyāya, Vaiśeṣika, Sāṁkhya, Mīmāṁsā as well as Buddhist and Jaina schools.