The paper undertakes a comparative philosophical study of the thought of René Descartes and Adi Shankaracharya, centring on the thematic convergence between the Cartesian dictum "Cogito, ergo sum" and the Vedāntic mahāvākya "Tat Tvam Asi", "Aham Brahmasmi", etc. Beginning with Descartes' method of methodological scepticism as articulated in Meditations on First Philosophy, the study highlights...