In Hinduism, Adhyatmavidya is the discipline pertaining to knowledge of the self. It is also known as anvikshiki. Kamandaka, in his Nitishastra says, “Since through anvikshiki, one investigates the causes of happiness and suffering, it is called atmavidya, or adhyatmavidya. Enquiring into the true nature of one’s self through it, one frees oneself from both joy and sorrow.”
In Upanishads, it is part of a triple statement – physical (adhibhuta), mental (adhidaiva), and of the self (adhyatma). This indicates the uniformity of the constitution of the marcroosm and microcosm, underlying both of which is the non-dual Self which, in its intrinsic nature, is a pure, absolute being that is conscious of its unity and infinity. On critical enquiry, it is found to be one’s inmost core, a dimension of one’s own being that transcends physical and mental planes.
The Bhagavad Gita (8.3) states. “Akshara is the Supreme, immutable Brahman and its self-identity, viz., ‘I-ness’ is adhyatma”. Adi Shankaracharya commenting on this phrase says “The self-dentity or ‘I-ness’ of that supreme, immutable Brahman with regard to each of the bodies is the order of svabhava (nature) or adhyatma. Hence with regard to one’s body which one regards as oneself, one proceeds inwards in quest of one’s real nature and concludes with the supreme reality, namely, Brahman, as one’s true being and this is called adhyatma.
The determination of the truth of the self, being the basis of all schools of thought, is held as the highest science. In the Bhagavad Gita, Bhagavan declares, ‘ I am adhyatmavidya among all the sciences and schools of thought (as it means of liberation –the existential goal of all human endeavor). Kamandaka, therefore, further state, “Anvikshiki is forever considered by the sages to be the lamp for all sciences, the tools for all actions, and the basis for all dharmas.