philosophical position. According to Vasubandhu: "Those who hold 'all exists' — the past, the present and the future — belong to the Sarvāstivāda. Those, on the other hand, who hold that some exist, viz., the present and the past karma that has not given fruit but not those that have given fruit or the future, are followers of the Vibhajyaväda." Vasubandhu initially wrote in favor of Sarvāstivāda, and later critiqued this position. The Sarvāstivāda-Vaibhāṣika also held an atomistic conception of time which divided time into discrete indivisible moments (kṣaṇa) and saw all events as lasting only for a minute instant (and yet also existing in all three times). Theravadins also held a theory of momentariness (Khāṇavāda), but it was less ontological than Sarvāstivāda and more focused on the psychological aspects of time. The Theravada divided every dhamma into three different instants of origination (uppādakkhaṇa), endurance (ṭhitikkhaṇa) and cessation (bhaṅgakkhaṇa). They also held that only mental events were momentary, material events could endure for longer. Rebirth and personal identity A key problem which the Abhidharmikas wished to tackle was the question of how rebirth and karma works if there is no self to be reborn apart from the five aggregates. The Patthana includes the earliest Pali canonical reference to an important answer to this question: bhavanga, or 'life-continuum'. Bhavanga, literally, "the limb on which existence occurs" is 'that substratum which maintains the continuity of the individual throughout that life.' The Sarvastivadins had a similar term, nikayasabhagata. This concept is similar to the Yogacara doctrine of the storehouse consciousness (alayavijnana), which was later associated with the Buddha nature doctrine. This problem was also taken up by a group of Buddhist schools termed the Pudgalavadins or "Personalists" which included the Vātsīputrīya, the Dharmottarīya, the Bhadrayānīya, the Sammitiya and the Shannagarika. These schools posited the existence of a 'person' (pudgala) or self, which had a real existence that was not reducible to streams and collections of dharmas. They also often used other terms to refer to this real 'self', such as 'Atman' and 'Jiva' which are words for the immortal soul in Hinduism and Jainism respectively. They seemed to have held that the 'self' was part of a fifth category of existence, the “inexpressible”. This was a radically different view than the not-self view held by the mainstream Buddhist schools and this theory was a major point of controversy and was thoroughly attacked by