Isvarakrsna (Sanskrit: ईश्वर कृष्णः Chinese: 自在黑; pinyin: Zìzàihēi) (5th century AD) is the author of the Samkhyakarika, an early account of the universe and its components (tattvas) according to the Samkhya school. Samkhya is one of the oldest of the six traditional systems of Indian philosophy which is attributed to the sage Kapila, but may have originated in the non-vedic Śramaṇa tradition.
Samkhya philosophy is said to have inspired Buddha, and versions of the Samkhya system are still used in many schools of Buddhism. Samkhya is also the basis for the Yoga school. Different versions of this system are also used in Vaisnavism and Saivism.