In the supplied Māṇḍūkya Upaniṣad (mūla) attestations, caturtha ("the fourth") designates the fourth and final ātman-condition named after the three prior quarters (which the verses describe via their cognitive modes — inward-, outward-, and unified/dense-cognition). It is characterized negatively and apophatically: not inwardly-cognizing, not outwardly-cognizing, not both, not a mass of cognition, neither cognizing nor non-cognizing; unseen, beyond dealings, ungraspable, without distinguishing marks, unthinkable, indefinable; its essence is the certainty of the one ātman, the cessation of manifoldness, peaceful, auspicious (śiva), and non-dual (advaita). At MU 12 it is further equated with the measureless (amātra) oṃkāra, which is ātman alone, into which the knower enters by the self. The two attestations agree in content; no interpretive split appears within them.
Senses
The reading surface. A later ingestion attaches a locus to a settled sense, or proposes a new one (dashed) for human triage — it never rewrites settled prose.
1 · The 'fourth' ātman-condition, characterized apophatically — beyond inward, outward, and un…settledadded v1
The 'fourth' ātman-condition, characterized apophatically — beyond inward, outward, and unified cognition; ungraspable, unthinkable, indefinable; essence is the certainty of the one ātman, cessation of manifoldness, peaceful, auspicious (śiva), and non-dual (advaita). It is what 'they consider' to be the fourth, and it is identified as the ātman.
upaniṣadic
mandukya.upanisad:7mandukya.sankarabhasya:7
2 · The 'fourth' as measureless (amātra), beyond dealings, the cessation of manifoldness, ausp…settledadded v1
The 'fourth' as measureless (amātra), beyond dealings, the cessation of manifoldness, auspicious and non-dual — equated with the oṃkāra that is ātman alone, into which the knower enters by the self.
upaniṣadic
mandukya.upanisad:12mandukya.sankarabhasya:12
3 · The 'fourth' (turīya) as the ātman that is lord (īśāna/prabhu) over the cessation of all s…proposedadded v2
The 'fourth' (turīya) as the ātman that is lord (īśāna/prabhu) over the cessation of all suffering belonging to the three states (prājña, taijasa, viśva); imperishable (avyaya), never deviating from its own nature.
Śaṅkara (bhāṣya)
Why a new sense: Characterizes turīya as lord over duḥkha-cessation and as imperishable/non-deviating — a positive soteriological framing not present in the apophatic s1 or the oṃkāra-equated s2.
mandukya.agamasastrabhasya:1.10
4 · The 'fourth' as the supremely hard-to-perceive (durdarśa), profound state free of the four…proposedadded v2
The 'fourth' as the supremely hard-to-perceive (durdarśa), profound state free of the four logical alternatives (catuṣkoṭi-varjita), unborn (aja), equal/uniform (sāmya), and free of manifoldness — graspable only by the accomplished in wisdom.
Śaṅkara (bhāṣya)
Why a new sense: Frames the fourth via the catuṣkoṭi negation, profundity, and unbornness (aja) — a distinct apophatic-logical characterization not captured by s1's specific triad-transcendence or s2's oṃkāra equation.
mandukya.agamasastrabhasya:4.100
Attestation concordance — tier 2, every locus
Append-only. Grows by locus as texts arrive; stays one collapsed table so the senses remain the reading surface.
All 6 attestations ▾
Locus
Witness
Tradition
Stratum
Snippet
mandukya.upanisad:7
Māṇḍūkya (mūla)
upaniṣadic
mula
nāntaḥprajñaṃ na bahiḥprajñaṃ nobhayataḥprajñaṃ na prajñānaghanaṃ na prajñaṃ nāprajñam | adṛṣṭam avyavahāryam agrāhyam alakṣaṇam acintyam avyapadeśyam
mandukya.upanisad:12
Māṇḍūkya (mūla)
upaniṣadic
mula
amātraś caturtho 'vyavahāryaḥ prapañcopaśamaḥ śivo 'dvaitaḥ | evam oṃkāra ātmaiva | saṃviśaty ātmanātmānaṃ ya evaṃ veda
mandukya.sankarabhasya:7
Śaṅkara (bhāṣya)
advaita-vedānta
bhasya
nanv ātmanaś catuṣpātvaṃ pratijñāya prādatrayakathanena eva caturthasyāntaḥ prajñādibhyo anyatve siddhe nāntaḥ prajña ityādi pratiṣedho 'narthakaḥ / n
mandukya.agamasastrabhasya:1.10
Śaṅkara (bhāṣya)
advaita-vedānta
bhasya
prājñataijasaviśvalakṣaṇānāṃ sarvaduḥkhānāṃ nivṛtte īśānas turīya ātmā / īśāna ity asya vyākhyānaṃ prabhur iti / duḥkhanivṛttiṃ prati prabhur bhavatīt
mandukya.sankarabhasya:12
Śaṅkara (bhāṣya)
advaita-vedānta
bhasya
amātro mātrā yasya nāsti sa amātra oṃkāraś caturthas turīya ātmaiva kevalo 'bhidhānābhidheyarūpayor avāṅmanasayoḥ kṣīṇatvād avyavahāryaḥ / prapañca up
mandukya.agamasastrabhasya:4.100
Śaṅkara (bhāṣya)
advaita-vedānta
bhasya
durdarśaṃ duḥkhena darśanamasyeti durdarśam, asti nāstīti catuṣkoṭivarjitatatvāddurvijñeyamityarthaḥ / ata evātigambhīraṃ duṣparveśaṃ mahāsamudravadak
Editions & provenance
v1Māṇḍūkya mūla + Gauḍapāda kārikā — +2 loci 2 sense(s) drafted from 2 loci.
v2Śaṅkara bhāṣya — +4 loci · 2 routed to existing · 2 new sense(s) proposed s1 fits locus 7: the fourth is identified as ātman/turīya by its difference from the three quarters — the 'they consider' apophatic framing. s2 fits locus 12: explicit equation of caturtha=turīya with the measureless (amātra) oṃkāra that is ātman alone, with prapañca-upaśama, śiva, advaita — matching s2 verbatim in substance. Loci 1.10 and 4.100 each carry characterizations (lordship over suffering-cessation/imperishability; catuṣkoṭi-negation/unbornness/sāmya) not represented in the existing two senses, so each is proposed as a new sense.
Caveats
The supplied corpus is a single tradition/text only — the Māṇḍūkya Upaniṣad mūla — and contains only two attestations; the entry's scope is limited accordingly.
No commentary loci (Gauḍapāda or Śaṅkara) were supplied. The suggested glosses equating caturtha with turīya and the gloss 'caturthas turīyaḥ' rest on commentary not present in the attestations, so no such equation or commentary position can be attributed here. Within the supplied mūla, the term turīya does not appear; only caturtha is attested.
The senses are drawn from usage in the two verses; the description of the three prior 'quarters' that caturtha is set against is inferred from the apophatic negations within these loci, not from separately supplied attestations of those quarters.