Advaitam — Non-Dualism
Advaitam (Sanskrit: a — not; dvaita — two; literally, not-two) is the school of Vedānta associated above all with Śaṅkarāchārya (circa 8th century CE). It holds that Brahman — the single, undifferentiated, absolute consciousness — is the only ultimately real entity. The apparent multiplicity of the world, the apparent individuality of finite souls, and the apparent distinction between jīva and Brahman are all generated by avidyā (ignorance): a cosmic and individual veil that causes the appearance of differentiation where none in fact exists. The goal of the Advaitin seeker is to realise, through jñāna (knowledge), that the individual self (ātman) is fully and without remainder identical to Brahman.
Within the Śrī Vaiṣṇava tradition, Advaitam is regarded as kudṛṣṭi — a philosophical position inconsistent with the testimony of the Vedas and the lived experience of devotion. Rāmānuja's principal critique of Advaitam, set out rigorously in the Śrī Bhāṣyam, targets the doctrine of avidyā: if Brahman is pure, perfect, omniscient consciousness, then avidyā — which is presumed to be powerful enough to conceal that very perfection — would have to be stronger than Brahman itself, making ignorance the supreme power in the cosmos. This, Rāmānuja argues, is both philosophically untenable and contradicted by every Vedic passage that asserts Brahman's absolute supremacy.
Viśiṣṭādvaitam offers an alternative resolution: the unity of Brahman is real, but it is the unity of a whole that genuinely possesses parts — souls and matter as its real, inseparable body.