In Hinduism, self-knowledge is a principal means of realizing God. Śaṅkara, the great Advaita Vedānta philosopher and mystic, distinguishes between direct, immediate knowledge and empirical, mediated knowledge. True knowledge is the immediate realization attained when the self (jīva) reaches turīya — the "fourth state" or knowledge that wells up from within. This descriptive-analytical study answers two questions: First, from Śaṅkara's perspective, what is the nature of the stages the self (jīva) undergoes to achieve certain knowledge, and how do these stages differ? Second, what are turīya's characteristics, and does this journey constitute merely an epistemological progression or also an ontological transformation? Findings show Śaṅkara, distinguishing jīva from Ātman, maintains that to attain certain knowledge, the self must pass through three states — waking, dreaming, and deep sleep — and finally reach turīya, the culmination of all stages. In turīya, the identity of Ātman and Brahman — the ultimate goal of human knowledge — is revealed. Moreover, analysis of Śaṅkara's works shows this process represents the self's (ātman) states of consciousness. Nevertheless, given Śaṅkara's commentaries on certain Upaniṣads, one can also draw ontological interpretations from these states.