Not inwardly conscious, not outwardly conscious, not in both directions; not a mass of consciousness, neither conscious nor unconscious; unseen, ungraspable, beyond inference, indefinable, unthinkable, beyond designation — the essence of the conviction of the one Self, the cessation of all phenomena, tranquil, auspicious, non-dual: that is the Fourth (Turiya). That is the Self; That is to be known.
Mandukya Upanishad
माण्डूक्योपनिषद्
मूल श्लोकः
नान्तःप्रज्ञं न बहिःप्रज्ञं नोभयतःप्रज्ञं न प्रज्ञानघनं न प्रज्ञं नाप्रज्ञम्। अदृष्टमव्यवहार्यमग्राह्यमलक्षणमचिन्त्यमव्यपदेश्यमेकात्मप्रत्ययसारं प्रपञ्चोपशमं शान्तं शिवमद्वैतं चतुर्थं मन्यन्ते स आत्मा स विज्ञेयः॥
nāntaḥ-prajñaṁ na bahiḥ-prajñaṁ nobhayataḥ-prajñaṁ na prajñāna-ghanaṁ na prajñaṁ nāprajñam adṛṣṭam avyavahāryam agrāhyam alakṣaṇam acintyam avyapadeśyam ekātma-pratyaya-sāraṁ prapañcopaśamaṁ śāntaṁ śivam advaitaṁ caturthaṁ manyante sa ātmā sa vijñeyaḥ
MaU 1.7