Reincarnation is an inclusive term for a handful of very different concepts about what happens to people after death. Its precise definition in Hinduism and Buddhismis is subtle and often poorly understood. Buddhism and Hinduism share some essential beliefs -- and feature stark differences. The nature and immortality of the soul is one area where the two faiths seem similar but actually disagree.

Hindu Reincarnation

Reincarnation in the Hindu religion is a journey through many lifetimes, from samsara to moksha. The endless repetition of birth, death and rebirth, called samsara, is a painful process of inching toward perfect merit, working off bad deeds, and achieving moksha or liberation. Hindus believe all living things have a soul that is not destroyed by death. After the soul leaves the body, at the moment of death, it is eligible for rebirth as human, animal, vegetable or mineral. The greater the merits accumulated over all lifetimes, the higher the rebirth. Many rituals and offerings are invoked in Hinduism to counter the negative effect of past sins and improve the chances of an auspicious rebirth. Hindus believe in the transmigration of an individual soul that survives lifetime after lifetime, a concept distinct from Buddhist beliefs about reincarnation.

Karma and Coming Back

The question of karma confuses people but a clue to its meaning is in the word itself. Karma means "action." Karma can be thought of as "good action yields good results, bad action yields bad results." What occurs during the course of a life informs subsequent lifetimes, according to Hindu scripture, but it does not dictate the future. Each person has the freedom to make choices that will earn merit or dishonor and influence the course of their present as well as future life. Transmigration of the soul, a Hindu belief, allows for switching species. There is no guarantee a soul will reincarnate as a human -- or even an animal -- in the next life.

Energy, Existence and Enlightenment

Buddhists do not believe there is a "thing," self or personality who goes through life, death and rebirth into another body. Buddhist reincarnation can be understood as consciousness, the creative principle, manifesting endlessly in new forms. A life is considered to be like a wave in the ocean. It appears to have form and then it is gone, vanished back into the sea. Meanwhile, the vast ocean exists, containing all waves, all water, with new waves continually arising and subsiding. Consciousness is energy, and all energy is one connected field, like drops of water in the ocean. Nirvana is simply the state of consciousness in which attachment and craving have been released and the bliss of perfect freedom is experienced. A blameless life earns rebirth into a more highly-evolved consciousness, a step closer to Nirvana or enlightenment.

Bodhisattvas

In Buddhism, one karmic choice results in rebirth after rebirth and presents a special case in the study of reincarnation. A bodhisattva is an enlightened being who takes a vow to delay existence in Nirvana until all beings are enlightened. This is the highest expression of Buddhist compassion and an exception to the general process of death and rebirth. The great Tibetan tulkus are bodhisattvas, reincarnate lamas who return to continue teaching others the Buddhist truths. Guan Yin is a revered bodhisattva in many Buddhist cultures, worshiped as the goddess of compassion. Buddhists who are still working toward enlightenment may take bodhisattva vows to ensure that once they reach a permanent state of bliss, they don't remain there but are reborn endlessly to help everyone become a buddha, or realized being.