Indian philosophy originated in ancient India and consists of several traditions of philosophical thought. It conceives of humans as spiritual beings related to a spiritual or metaphysical universe. Intuition, rather than intellect, is seen as the path to ultimate truth. The key schools of thought include orthodox Hindu schools like Nyaya, Vaisheshika, Samkhya, Yoga, Mimamsa and Vedanta as well as heterodox schools like Carvaka, Buddhism, and Jainism. Indian philosophy has developed over periods from the Vedic era to the modern day, addressing concepts like the nature of reality, the self, karma, rebirth, liberation and different paths to enlightenment.