 Despite the phenomenological character that atoms sometimes bear in Buddhist thought, questions about compositionality occur which parallel issues in other ancient atomist theories (Goodman 2004, Carpenter 2021). Vaiśeṣika thought—which accepted categories like substance and soul—impacted the articulation of Abhidhamma ontology, an articulation that sometimes led to charges of ‘ontologization,’ i.e. of moving away from the experiential focus of Buddhist thought towards a more systematic metaphysics (Ronkin 2005). Material atoms are first found in Buddhist thought in the work of Dharmasri (2nd c. CE), and feature in the work of Vasubandhu and Sanghabhadra (both 5th c. CE) (Ronkin 2005, 56).