Reincarnation is the philosophical or religious concept that an aspect of a living being starts a new life in a different physical body or form after each biological death. It is also called rebirth or transmigration, and is a part of the Saṃsāra doctrine of cyclic existence. It is a central tenet of all major Indian religions, namely Jainism, Hinduism, Buddhism, and Sikhism. The idea of reincarnation is found in many ancient cultures, and a belief in rebirth/metempsychosis was held by Greek historic figures, such as Pythagoras, Socrates, and Plato. It is also a common belief of various ancient and modern religions such as Spiritism, Theosophy, and Eckankar, and is found as well in many tribal societies around the world, in places such as Australia, East Asia, Siberia, and South America.
Although the majority of denominations within the Abrahamic religions of Christianity, Judaism, and Islam do not believe that individuals reincarnate, particular groups within these religions do refer to reincarnation; these groups include the mainstream historical and contemporary followers of Kabbalah, the Cathars, Alawites, the Druze, and the Rosicrucians. The historical relations between these sects and the beliefs about reincarnation that were characteristic of Neoplatonism, Orphism, Hermeticism, Manicheanism, and Gnosticism of the Roman era as well as the Indian religions have been the subject of recent scholarly research. Unity Church and its founder Charles Fillmore teaches reincarnation.
The word "reincarnation" derives from Latin, literally meaning, "entering the flesh again". The Greek equivalent metempsychosis (μετεμψύχωσις) derives from meta (change) and empsykhoun (to put a soul into), a term attributed to Pythagoras. An alternate term is transmigration implying migration from one life (body) to another. Reincarnation refers to the belief that an aspect of every human being (or all living beings in some cultures) continues to exist after death, this aspect may be the soul or mind or consciousness or something transcendent which is reborn in an interconnected cycle of existence; the transmigration belief varies by culture, and is envisioned to be in the form of a newly born human being, or animal, or plant, or spirit, or as a being in some other non-human realm of existence. The term has been used by modern philosophers such as Kurt Gödel and has entered the English language. Another Greek term sometimes used synonymously is palingenesis, "being born again".
Rebirth is a key concept found in major Indian religions, and discussed with various terms. Punarjanman (Sanskrit: पुनर्जन्मन्) means "rebirth, transmigration". Reincarnation is discussed in the ancient Sanskrit texts of Hinduism, Buddhism, and Jainism, with many alternate terms such as punarāvṛtti (पुनरावृत्ति), punarājāti (पुनराजाति), punarjīvātu (पुनर्जीवातु), punarbhava (पुनर्भव), āgati-gati (आगति-गति, common in Buddhist Pali text), nibbattin (निब्बत्तिन्), upapatti (उपपत्ति), and uppajjana (उप्पज्जन). These religions believe that this reincarnation is cyclic and an endless Saṃsāra, unless one gains spiritual insights that ends this cycle leading to liberation. The reincarnation concept is considered in Indian religions as a step that starts each "cycle of aimless drifting, wandering or mundane existence", but one that is an opportunity to seek spiritual liberation through ethical living and a variety of meditative, yogic (marga), or other spiritual practices. They consider the release from the cycle of reincarnations as the ultimate spiritual goal, and call the liberation by terms such as moksha, nirvana, mukti and kaivalya. However, the Buddhist, Hindu and Jain traditions have differed, since ancient times, in their assumptions and in their details on what reincarnates, how reincarnation occurs and what leads to liberation.
Gilgul, Gilgul neshamot or Gilgulei Ha Neshamot (Heb. גלגול הנשמות) refers to the concept of reincarnation in Kabbalistic Judaism, found in much Yiddish literature among Ashkenazi Jews. Gilgul means "cycle" and neshamot is "souls". Kabbalistic reincarnation says that humans reincarnate only to humans and to the same sex only: men to men, women to women.
The origins of the notion of reincarnation are obscure. Discussion of the subject appears in the philosophical traditions of India. The Greek Pre-Socratics discussed reincarnation, and the Celtic Druids are also reported to have taught a doctrine of reincarnation.