  The Buddhist epistemologists adopt a parsimonious epistemology: only  two sources or instruments of cognition (pramāṇa) are accepted are reliable: perception (pratyakṣa) and  inference (anumāna). Dignāga gives a most basic  reason why we ought to accept only these two sources as warranted:  that is, because there are only two types of objects, those bearing  their own characteristic mark (i.e., particulars) and those whose  characteristic is that of universality (i.e., universals), each  corresponding to a specific mode of apprehension (PSV ad I,  2; Hattori 1968, 24, 79). What we have here is an attempt to  translate the two fundamental categories of particular and universal  back to their specific knowledge source: particulars to perception  and universals to inferential reasoning. Dignāga, thus, appears  to be claiming that all objects of cognition, whether external or  internal, cannot be properly understood if separated from the types  of cognitive events in which they are instantiated, a view best  described as phenomenalism.