primarily with what makes categorial types of dharma unique, rather than with the ontological status of dharmas." However, in the later Sarvastivada texts, like the Mahavibhasa, the term svabhava began to be defined more ontologically as the really existing “intrinsic nature” specifying individual dharmas. The Sautrantika school accepted the doctrine of svabhāva as referring to the distinctive or main characteristic of a dharma, but rejected the view that they exist in all three times . The Buddhist philosopher Dharmakirti uses the concept of svabhāva, though he interprets it as being based on causal powers. For Dharmakirti, the essential nature (or ‘nature-svabhāva’) is:“The arising of an effect that is inferred by way of a causal complex is characterized as a svabhāva of that causal complex, because [the capacity for] the effect’s production does not depend on anything else.” Other early Buddhist schools did not accept the svabhava concept, instead positing a kind of nominalism or conceptualism (prajñaptivada). This view was widespread among the Mahasamghika Nikaya. One school was even called "Prajñaptivada" because of their denial of the ultimate reality of all dharmas and their view that all dharmas are characterized by prajñapti (provisional designation or fictitious construction). Another school called the Vainasikas also held that all dharmas were without svabhava. According to Paramārtha (499–569), another school, the Ekavyavahārikas held "that both the mundane and the supramundane factors [dharmas] are merely nominal (prajñapti). They therefore claimed that all factors have no real essence, and that hence the same name applies to all [dharmas]." This helps to explain their name as “Ekavyavahārika” (those who propound the single meaning). Paramārtha also notes that the Lokottaravāda school held "that the mundane factors have arisen from perversion (viparyāsa) and are only nominal (prajñapti)." However, in contrast to the other schools, they also held that the supramundane dharmas (nirvana etc.) were not nominal but real. This view that dharmas are empty or void is also found in the Lokānuvartana-sūtra (‘The Sutra of Conformity with the World’, Taisho No.807) which survives in Chinese and Tibetan translation, and may have been a scripture of the Purvasailas, which was a sub-school of the Mahasamghika. Causality and dependent origination Another important project for the Abhidharmikas was to outline a theory of causality, especially of how momentary dharmas relate to each other through causes and conditions. The Sarvastivadin analysis focused on six causes (hetu), four conditions (pratyaya) and five effects (phala). According