Aruni (fl. c. 8th century BCE), also referred to as Uddalaka or Uddalaka Aruni, is a revered Vedic sage of Hinduism. He is mentioned in many Vedic era Sanskrit texts, and his philosophical teachings are among the center piece in the Brihadaranyaka Upanishad and Chandogya Upanishad, two of the oldest Upanishadic scriptures. A famed Vedic teacher, Aruni lived a few centuries before the Buddha, during the times of 23rd Jina Parshvanatha, and attracted students from far regions of the Indian subcontinent; some of his students such as Yajnavalkya are also highly revered in the Hindu traditions. Both Aruni and Yajnavalkya are among the most frequently mentioned Upanishadic teachers in Hinduism.
According to Ben-Ami Scharfstein, a professor emeritus of Philosophy at Tel Aviv University, Uddalaka Aruni was one of the first philosophers in recorded history. In the Chandogya Upanishad Aruni asks metaphysical questions concerning the nature of reality and truth, observes constant change, and asks if there is something that is eternal and unchanging. From these questions, embedded in a dialogue with his son, he presents the concept of Ātman (soul, Self) and universal Self.
The name Aruni appears in many of the Principal Upanishads, in numerous verses. For example:
- In sections 3.7 and 6.2 of the Brihadaranyaka Upanishad, in a dialogue where Aruni is relatively a minor participant.
- In sections 6.1–16 and 5.3 of the Chandogya Upanishad, as a major dialogue between Aruni and his son Svetaketu, a dialogue about Atman and Brahman that contain ideas foundational to the Vedanta school of Hindu philosophy. The dialogue sets the context of the son, who goes to a Vedic school for twelve years of studies, is conceited that he has learnt the books (Vedas). Aruni, the father enquires and presses Svetaketu whether at school, he pondered and understood the nature of existence, what is truth, what is reality, the meaning of life and self-knowledge, and the relationship between oneself, other beings and the universal self.
- In verse 1.1 of the Kaushitaki Upanishad, where the scion of Gangya invites Aruni, but he sends his son to the event. This verse is notable for the conversation therein that suggests the full name of Aruni to be Uddalaka Aruni Gautama, and the mention of him as one of the characters in a group event that hosted "Vedic studies in the hall of sacrifice" (yajna).
- In the Katha Upanishad, which opens with the story of Vajasravasa, also called Aruni Auddalaki Gautama. According to Max Muller – an Indologist at Oxford University, assuming the manuscripts have been correctly reproduced over their history, there may be a difference between "Auddalaki" (grandson) and "Uddalaki" (son), but he adds Adi Shankara considered them to be same Aruni, in his commentaries on the Upanishads. The theme discussed in the dialogues of the Katha Upanishad is also Atman and Brahman. Paul Deussen, an Indologist at University of Kiel, states that there are inconsistencies about his full name in the Hindu traditions.