Prasthanatrayi (Sanskrit: प्रस्थानत्रयी, IAST: Prasthānatrayī), literally, three sources (or axioms), refers to the three canonical texts of theology having epistemic authority, especially of the Vedanta schools. It consists of:
- The Upanishads, known as Upadeśa Prasthāna (injunctive texts), and the Śruti Prasthāna (the starting point or axiom of revelation), especially the Principal Upanishads.
- The Bhagavad Gita, known as Sādhana Prasthāna (practical text), and the Smṛti Prasthāna (the starting point or axiom of remembered tradition)
- The Brahma Sutras, known as Sūtra Prasthāna (formulative texts) or Nyāya Prasthāna or Yukti Prasthāna (logical text or axiom of logic)
The Upanishads consist of ten, twelve or thirteen major texts, with a total of 108 texts (some scholars list ten as principal – the Mukhya Upanishads, while most consider twelve or thirteen as principal, most important Upanishads). The ten Upanishads are Īśā, Kena, Kaṭha, Praṣna, Muṇḍaka, Māṇḍūkya, Taittirīya, Aitareya, Chāndogya and Bṛhadāraṇyaka.