In Hindu philosophy, turiya (Sanskrit: तुरीय, meaning "the fourth"), also referred to as chaturiya or chaturtha, is the true self (atman) beyond the three common states of consciousness (waking, dreaming, and dreamless deep sleep). It is postulated in several Upanishads and explicated in Gaudapada's Mandukya Karika.
Upanishads
Turiya as 'the fourth' is referred to in a number of principal Upanishads. One of the earliest mentions of the phrase turiya, "fourth", is in verse 5.14.3 of the Brihadaranyaka Upanishad, referring to a 'fourth foot' of the Gayatri Mantra, the first, second and third foot being the 24 syllables of this mantra:
According to Raju, chapter 8.7 through 8.12 of the Chandogya Upanishad, though not mentioning turiya, 'anticipate' the Mandukya Upanishad and it's treatment of turiya. These verses of the Chandogya Upanishad set out a dialogue between Indra and Virocana, in search of atman, the immortal perceiver, and Prajapati, their teacher. After rejecting the physical body, the dream self, and the dreamless sleep (in which there is no perception of "I am") as atman, Prajapati declares in verse 12 to Indra that the mortal body is the abode of the "immortal and non-bodily self", which is the perceiver, the one who perceives due to the faculties of the senses.
The phrase "turiya" also appears in Maitri Upanishad in sections 6.19 (in the context of yoga) and 7.11:
Verse 7 of the Mandukya Upanishad refers to "the fourth" (caturtha), or "the fourth quarter", the first, second and third quarter being situated in the waking, dreaming and dreamless state:
Michael Comans disagrees with Nakamura's suggestion that "the concept of the fourth realm (caturtha) was perhaps influenced by the Sunyata of Mahayana Buddhism", stating that "[T]here can be no suggestion that the teaching about the underlying Self as contained in the Mandukya contains shows any trace of Buddhist thought, as this teaching can be traced to the pre-Buddhist Brhadaranyaka Upanishad."
According to Ellen Goldberg, this fourth quarter describes a state of meditation; the insight during meditation of Turiya is known as amātra, the 'immeasurable' or 'measureless' in the Mandukya Upanishad, being synonymous with samādhi in Yoga terminology.
AUM and four states of consciousness
In the Mandukya Upanishad, AUM symbolizes the four states of consciousness. The three parts in A-U-M corresponds to waking, dreaming, and sleep states. The fourth state, (turīya avasthā), corresponds to silence, just as the other three correspond to AUM. It is the substratum of the other three states. It is, states Nakamura, atyanta-shunyata (absolute emptiness). According to Sharma, Turiya is "the common ground of all these states. It manifests itself in these three states and yet in its own nature it transcends them all".
Advaita Vedanta
Gaudapada
Gaudapada, an early guru in Advaita Vedanta, was the author or compiler of the Mandukya Karika|, a commentary on the Māṇḍukya Upanishad, also known as the and as the . Gaudapada was influenced by Buddhism, though he was a Vedantin and not a Buddhist. In the , Gaudapada deals with perception, idealism, causality, truth, and reality. In his commentary on verse 7 of the Mandukya Upanishad, Gaudapada explains Turiya, the fourth state of consciousness, as the ultimate reality that transcends the waking, dreaming, and the deep sleep states. According to Gaudapada, Turiya is beyond cause and effect and is the pure, self-luminous consciousness in which all dualistic distinctions between subject and object cease to exist. The phenomenal world is an appearance produced by maya (illusion), while Turiya is the non-dual reality. For Gaudapada, turiya is the "true 'state' of experience," in which the infinite (ananta) and non-different (advaita/abheda) are apprehended.
Isaeva notes that the Mandukya Upanishad asserts that "the world of individual souls and external objects is just a projection of one indivisible consciousness (citta)," which is "identical with the eternal and immutable atman of the Upanisads [..] in contrast to momentary vijnana taught by the Buddhist schools."
Adi Shankara
Adi Shankara described, on the basis of the ideas propounded in the Mandukya Upanishad, the three states of consciousness, namely waking (jågrata), dreaming (svapna), and deep sleep (susupti):
- The first state is that of waking consciousness, in which we are aware of our daily world. "It is described as outward-knowing (bahish-prajnya), gross (sthula) and universal (vaishvanara)".