 Scholars differ among themselves regarding the classical period in Indian Philosophy, but here we will assume the classical period to reach from the end of the Vedic era to the beginning of the early modern age in the fifteenth century CE. Classical Indian philosophy is by no means a monolith but accommodates within it different systems which either admitted or denied the infallibility of the Vedas (the hallowed Revealed Scripture of the Hindus). The systems upholding the authority of the Vedas are Vedānta, Mīmāṃsā, Sāṃkhya, Yoga, Nyāya and Vaiśeṣika, while the systems that challenged its scriptural authority include Cārvāka materialism and various schools of Buddhism and Jainism. Naturalistic traits are available in these systems, but first it is necessary to determine the sense of naturalism relevant for the purpose at hand.