How does one know about the self, according to the three main schools discussed in my last post?
Buddhist Epistemological School (Dharmakīrti): the self does not exist. The only thing that exists is a stream (santāna) of causally linked momentary cognitions. Cognitions are self-aware of themselves qua cognitions (svasaṃvedana). This is not contradictory, because each cognition has a perceiver and a perceived aspect (grāhaka and grāhya-ākāra respectively).
Nyāya: the self is known only through inference (Vātsyāyana, Jayanta); it is known also through perception (Uddyotakara, Udayana)*
Bhāṭṭa Mīmāṃsā (Kumārila): we have direct access to our self through ahampratyaya `cognition of the I’. No need to infer it, since perception trumps inference and Mīmāṃsā authors require novelty as a criterion for knowledge, so that repeating what is already known through ahampratyaya would not count as knowledge.
The first Nyāya position might lead to problems if connected with the acceptance of yogic perception. Yogins can indeed perceive the self, according to all Naiyāyikas. Why not all other beings, given that perception requires a conjunction of self+manas+sense faculties, that the self is pervasive (vibhu) and that spatial limits are not needed for perception, as shown by the case of absence? Jayanta explains that the self is partless and that a partless thing cannot simultaneously be perceiver and perceived (cf. Kumārila’s argument against the Buddhist idea of cognitions’ having a perceiver and a perceived aspect and Kumārila’s claiming that this does not apply to the self, which is complex and not partless).
The Mīmāṃsā position requires the joint work of intrinsic validity and falsification: some I-cognitions are not about the ātman, since they are indeed falsified (e.g., “I am thin”, which only refers to the body).
Other I-cognitions are not, e.g., cognising ourselves qua knowers and recognising ourselves as the same knower who knew something in the past.
*I am grateful to Alex Watson for discussing the topic with me per email, on top of his decades of work on the topic!