Ratha Kalpana (from Sanskrit ratha 'chariot', and kalpana 'image') is a metaphor used in Hindu scriptures to describe the relationship between the senses, mind, intellect and the Self. The metaphor was first used in the Katha Upanishad and is thought to have inspired similar descriptions in the Bhagavad Gita, the Dhammapada and Plato's Phaedrus. Gerald James Larson, a scholar of Indian philosophies, believes that the chariot metaphor contains one of the earliest references to ideas and terminology of the Indian philosophical school Samkhya.