Ādi Śaṅkarācārya is remembered as the great systematizer who gathered the scattered non-dual insights of the Upaniṣads and earlier teachers into a coherent Advaita Vedānta. He articulated with great clarity that Brahman alone is the ultimate reality, while the world of multiplicity is explained through māyā and regarded as empirically experienced yet not absolutely real. Within this vision, the individual self (ātman) is not other than Brahman, and bondage arises from ignorance (avidyā), to be removed through liberating knowledge (jñāna). By organizing these ideas into a rigorous philosophical framework, he turned Advaita from a set of profound intuitions into a fully developed darśana.

A central part of this work lay in his commentaries on the Prasthāna-trayī: the principal Upaniṣads, the Bhagavad Gītā, and the Brahma Sūtras. These bhāṣyas became the standard lens through which Advaita interprets śruti, grounding non-dualism firmly in scripture and offering detailed refutations of rival schools such as Sāṅkhya, Buddhism, and other forms of Vedānta. In these works he also clarified a subtle hermeneutic: distinguishing absolute (pāramārthika) from empirical (vyāvahārika) levels of truth, and employing methods of negation and careful interpretation to reveal the non-dual substratum of all experience. Later Advaitins took these commentaries as their primary touchstone, elaborating but rarely departing from his basic structure.

Beyond commentary, Śaṅkara composed independent treatises that present Advaita in a more pedagogical and practical manner, such as the Upadeśa Sāhasrī and other works traditionally associated with his name. These texts spell out the qualifications of the seeker, the disciplines of śravaṇa, manana, and nididhyāsana, and the nature of direct realization as immediate, non-mediated knowledge of one’s identity with Brahman. In this way, philosophy and sādhanā are woven together: rigorous metaphysics is never divorced from the lived path of discrimination, renunciation, and contemplative insight. His writings also show how ritual action, devotion, and meditation can function as preparatory means, ultimately subordinated to and fulfilled in liberating knowledge.

Śaṅkarācārya’s contribution was not only textual and conceptual but also institutional. He is traditionally credited with founding four maṭhas in different regions of India and organizing the Daśanāmī order of saṃnyāsins, thereby creating enduring centers for the preservation and transmission of Advaita. Through debates and sustained engagement with opposing views, he secured a respected place for non-dualism within the wider landscape of Hindu thought. The result is that Advaita Vedānta, as shaped by Śaṅkara, stands as a complete vision: philosophically rigorous, scripturally grounded, spiritually practicable, and supported by a living lineage dedicated to the realization of the identity of ātman and Brahman.