Several scholars have recognised parallels between the philosophy of Pythagoras and Plato and that of the Upanishads, including their ideas on sources of knowledge, concept of justice and path to salvation, and Plato's allegory of the cave. Platonic psychology with its divisions of reason, spirit and appetite, also bears resemblance to the three gunas in the Indian philosophy of Samkhya.[note 9]
Based on these common features some scholars, most notably E.J. Urwick and M.L. West, have argued that the Ancient Greek philosophy was influenced by, and borrowed some core concepts from, the Upanishads. Various mechanisms for such a transmission of knowledge have been conjectured including Pythagoras traveling as far as India; Indian philosophers visiting Athens and meeting Socrates; Plato encountering the ideas when in exile in Syracuse; or, intermediated through Persia.
However other scholars, such as Arthur Berriedale Keith, J. Burnet and A.R. Wadia, believe that the two systems developed independently. They note that there is no historical evidence of the philosophers of the two schools meeting, and point out significant differences in the stage of development, orientation and goals of the two philosophical systems. Wadia writes that Plato's metaphysics were rooted in this life and his primary aim was to develop an ideal state. In contrast, Upanishadic focus was the individual, the self (atman, soul), self-knowledge, and the means of an individual's moksha (freedom, liberation in this life or after-life).