 A comparison with Hume may bring the tensions in Dharmakīrti’s position into better focus. Hume had famously said in Section 7 of his Enquiry Concerning Human Understanding: “We may define a cause to be an object followed by another, and where all the objects, similar to the first, are followed by objects similar to the second.” Causal connections are said to consist in contingent regularities established by observation. What the above-cited passage from the Pramāṇavārttikasvavṛtti suggests, however, is that for Dharmakīrti such mere regularities are somehow not enough and that something stronger is at stake: there are features “in” the causal relata themselves. Indeed his causal theory of properties allows him to assert that fire, being what it is, must cause smoke under the right conditions and that smoke, being smoke, must be caused by fire. That being said, there are also very important passages in Dharmakīrti’s works where he does speak of establishing causality because one observes an effect when there is a particular cause and does not observe it when that cause is absent. As in the case of Hume, this too is an observation of regularities and would seem to be fallible, subject to exceptions. It is the Indian method of observing successive co-presence (anvaya) and co-absence (vyatireka) and is a type of induction used throughout Indian philosophy to establish connections between two types of things. Dharmakīrti relies on a multi-step procedure that is sometimes explained in terms of a threefold combination of observations (upalabdhi) and non-observations (anupalabdhi) and sometimes in terms of five. Thus we have the so-called “triple” or “fivefold examination” (trikapañcakacintā) of causality that is developed by later Buddhist writers, such as Dharmottara, Jñānaśrīmitra and  Mokṣākaragupta.[27]  Other provisos are also added in an attempt to rule out certain bogus circumstances that would vitiate the procedure (see e.g., Lasic 1999). The details and problems cannot be taken up here. This method of anvaya and vyatireka has been profitably compared with J.S. Mill’s “Method of Agreement and Difference” to establish causation (see Matilal 1998,17; cf. Tillemans 2004, 265–269).