  Nyāya epistemology is in effect a theory of the true nonrecollective cognitions, and their division into four types on the basis of the different accredited epistemic means (pramāṇa-s) by which they are produced. (What about accidentally true cognitions, e.g. the result of a lucky guess? There are well-discussed problems with incorporating them into the above schema). It is clear that, no matter how generally reliable are our epistemic methods, it will always be possible for misfires to issue occasionally in false cognitions (e.g. perceptual illusions, beliefs resulting from a reporting error, etc.). The Manual of Reason’s example (TS 72) is of the false pseudo-perceptual judgement “This is a piece of silver” on seeing an oyster-shell. I will discuss the epistemology of perception, inference and testimony in §§ 7, 8 and 9 respectively. Here, I will examine in more detail three types of cognition which, though very important within the Nyāya framework, are subsidiary to its epistemology. They are: memory, ‘doubt’ and tarka. (Where do dreams fit in the schema? TS 70 states that they belong in the category of ‘false’ cognitions. This, however, is odd, since they are not the product of any of the four pramāṇas misfiring. Neither are they memories or states of doubt. According to Praśastapāda, dreams are the result of the free movement of the ‘mind’ when it is not connected with the external sense-faculties, influenced by adṛṣṭa, ‘unseen’ forces.)