Dharmakīrti's ultimately real ("paramārthasat") particulars are contrasted with conventionally real entities ("saṃvṛtisat") as part of his presentation of the Buddhist Two truths doctrine. The conventionally real for him are based on linguistic categories, intellectual constructs and erroneous superimpositions on the flow of reality, such as the idea that universals exist. According to Dharmakīrti, cognitive distortion of the direct perception of particulars occurs during the process of recognition ("pratyabhijñāna") and perceptual judgment ("niścaya") which arises due to latent tendencies ("vāsanā") in the mind left over from past impressions of similar perceptions. These latent dispositions come together into constructed representations of the previously experienced object at the moment of perception, and hence it is an imposed error on the real, a pseudo-perception ("pratyakṣābhāsa") which conceals ("saṃvṛti") reality while at the same time being practically useful for navigating it. Ignorance ("avidyā") for Dharmakīrti is conceptuality, pseudo-perception and superimposition overlaid on the naturally radiant ("prabhāsvara") nature of pure perception. By correcting these defilements of perception through mental cultivation as well as using inference to gain "insight born of (rational) reflection" ("cintāmayī prajñā") a Buddhist yogi is able to better see the true nature of reality until his perception is fully perfected.