Ratha Kalpana (from Sanskrit ratha, meaning 'chariot', and kalpana, meaning '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.
Ratha Kalpana is used, in the third chapter of Katha Upanishad, as a device to explain the hierarchy of various levels of existence. In this context, spiritual practice is seen as a return to consciousness through the levels of manifested existence. The metaphor forms a part of the teaching imparted to Nachiketa, a child seeking knowledge about life after death, by Yama, the Hindu god of death. It follows an instruction by Yama on the difference between preya (pleasant) and shreya (good).[a] William K. Mahony, in , writes, "We have in this metaphor an image of a powerful process that can either lead to fulfillment or in which the seeker can become lost."The Artful Universe: An Introduction to the Vedic Religious Imagination
Verses 1.3.3–11 of Katha Upanishad deal with the allegoric expression of an individual as a chariot. The body is equated to a chariot where the horses are the senses, the reins are the mind, and the charioteer is the intellect. The master of the chariot is the Self, on forgetting which the charioteer intellect becomes absorbed in the field of action. The verses conclude by describing control of the chariot and contemplation on the Self as ways by which the intellect acquires Self Knowledge.
He who has the understanding of the driver of the chariot and controls the rein of his mind,
he reaches the end of the journey, that supreme abode of the all–pervading