This article discusses a peculiar Sā$$\dot {\text{n}}$$n˙khya-Yoga theory of transformation (pariṇāma) that the author of the Pātañjalayogaśāstra created by drawing upon Sarvāstivāda Buddhist theories of temporality. In developing his theory, Patañjali adaptively reused the wording in which the Sarvāstivāda theories were formulated, the specific objections against these theories, and their refutations to win the philosophical debate about temporality against Sarvāstivāda Buddhism. Patañjali’s approach towards the Sarvāstivāda Buddhist theories was possible, even though his system of Yoga is based on an ontology (...) that differs considerably from that of Sarvāstivāda Buddhism because both systems share the philosophical view that time is not a separate ontological entity in itself. Time is a concept deduced from change in the empirical world. This agreement results from the common philosophical orientation of Sarvāstivāda Buddhism and Yoga, which takes the phenomenon of experience as the basis of philosophical enquiry into the structure of the world. The intention that guided Patañjali’s adaptive reuse was twofold. On the one hand, he aimed at winning the debate with Sarvāstivāda Buddhism about how the problem of temporality can be solved. He thus integrated four mutually exclusive theories on temporality into a single theory of transformation of properties (dharma) involving a second-level and a third-level theory on the transformation of the temporal characteristic mark (lakṣaṇa) and on the transformation of states (avasthā), respectively. On the other hand, Patañjali intended to achieve philosophical clarification regarding the question of how exactly properties relate to their underlying substrate in the process of transformation of the three constituents or forces (guṇa) sattva, rajas and tamas of matter (pradhāna) that account for all phenomena of the world except pure consciousness (puruṣa). Patañjali’s theory of transformation is thus of central importance for his Sā$$\dot {\text{n}}$$n˙khya ontology, according to which the world consists of 25 categories or constituents (tattva), i.e., of primal matter (prakṛti) and its transformations and pure consciousness. (shrink)