Indian philosophy

India has a rich and diverse philosophical tradition dating back to the composition of the Upanisads in the later Vedic period. According to Radhakrishnan, the oldest of these constitute "...the earliest philosophical compositions of the world."[1]

Since the late medieval age (ca.1000-1500)[2] various schools (Skt: Darshanas) of Indian philosophy are identified as orthodox (Skt: astika) or non-orthodox (Skt: nastika) depending on whether they regard the Veda as an infallible source of knowledge.[3] There are six schools of orthodox Hindu philosophy and three heterodox schools. The orthodox are Nyaya, Vaisesika, Samkhya, Yoga, Purva mimamsa and Vedanta. The Heterodox are Jain, Buddhist and materialist (Cārvāka). However, Vidyāraṇya classifies Indian philosophy into sixteen schools where he includes schools belonging to Saiva and Raseśvara thought with others.[4]

The main schools of Indian philosophy were formalised chiefly between 1000 BC to the early centuries AD. Subsequent centuries produced commentaries and reformulations continuing up to as late as the 20th century by Aurobindo and Prabhupada among others. Competition and integration between the various schools was intense during their formative years, especially between 800 BC to 200 AD. Some like the Jain, Buddhist, Shaiva and Advaita schools survived, while others like Samkhya and Ajivika did not, either being assimilated or going extinct. The Sanskrit term for "philosopher" is dārśanika, one who is familiar with the systems of philosophy, or darśanas.[5]

Common themes

The Indian thinkers of antiquity (very much like those of the Hellenistic schools) viewed philosophy as a practical necessity that needed to be cultivated in order to understand how life can best be led. It became a custom for Indian writers to explain at the beginning of philosophical works how it serves human ends (puruṣārtha).[6] Recent scholarship has shown that there was a great deal of intercourse between Greek and Indian philosophy during the era of Hellenistic expansion.[7]

Indian philosophy is distinctive in its application of analytical rigour to metaphysical problems and goes into very precise detail about the nature of reality, the structure and function of the human psyche and how the relationship between the two have important implications for human salvation (moksha). Rishis centred philosophy on an assumption that there is a unitary underlying order (rta) in the universe[8] which is all pervasive and omniscient. The efforts by various schools were concentrated on explaining this order and the metaphysical entity at its source (Brahman). The concept of natural law (