Sāmānādhikaraṇya — The Grammar of Non-Dual Unity
Sāmānādhikaraṇya (Sanskrit: sāmāna = common + adhikaraṇa = locus/substrate; 'sharing a common locus') is a technical grammatical and philosophical concept meaning that two different words with different primary meanings both apply to the same locus or substrate.
The Key Example: 'Brahman is Paramātman' — here two words (Brahman, Paramātman) with different conventional meanings co-refer to the same ultimate Reality. This co-reference is sāmānādhikaraṇya. It does not erase the difference in their meanings, but reveals that both qualities inhere in one Reality.
Viśiṣṭādvaita Interpretation: Śrī Rāmānuja uses sāmānādhikaraṇya to explain Mahāvākyas like 'tat tvam asi' (That thou art). In Advaita, this is interpreted as pure identity — soul = Brahman. In Viśiṣṭādvaita, it is interpreted as viśiṣṭa-sāmānādhikaraṇya — qualified identity-in-difference: the individual self (tvam) is qualified by, and non-separate from, Brahman (tat), as body relates to soul. Difference is real but not ultimate separation.
Śarīra-Śarīrī Bhāva: Sāmānādhikaraṇya is the grammatical expression of the body-soul relationship. 'The world is Brahman's body' — yet world and Brahman are different in nature. The Upaniṣadic statements that seem to equate self and Brahman are understood through this lens: qualified co-reference, not crude identity.