 Two problems loom large in Dignāga’s account: (1) What are the necessary and sufficient conditions of a source of knowledge (pramāṇa) and when are we justified in thinking that these conditions are met? (2) Given that only perception has direct access to the real and is causally bound to it, how is it that conceptual thought could ever be about real particulars at all and be considered a genuine source of knowledge? We’ll take up the questions one by one.