Reincarnation is the religious or philosophical concept that the soul or spirit, after biological death, begins a new life in a new body that may be human, animal or spiritual depending on the moral quality of the previous life's actions. This doctrine is a central tenet of the Indian religions. It is also a common belief of various ancient and modern religions such as Spiritism, Theosophy, and Eckankar and is found in many tribal societies around the world, in places such as Siberia, West Africa, North America, and Australia
The entire universal process that gives rise to the cycle of death and rebirth, governed by karma, is referred to as Samsara while the state one is born into, the individual process of being born or coming into the world in any way, is referred to simply as "birth"
The Buddha lived at a time of great philosophical creativity in India when many conceptions of the nature of life and death were proposed.
The Buddhist concept of reincarnation differs from others in that there is no eternal "soul", "spirit" or "self" but only a "stream of consciousness" that links life with life. The actual process of change from one life to the next is called punarbhava (Sanskrit) or punabbhava (Pāli), literally "becoming again", or more briefly bhava, "becoming", and some English-speaking Buddhists prefer the term "rebirth" or "re-becoming" to render this term as they take "reincarnation" to imply a fixed entity that is reborn. Popular Jain cosmology and Buddhist cosmology as well as a number of schools of Hinduism posit rebirth in many worlds and in varied forms. In Buddhist tradition the process occurs across five or six realms of existence, including the human, any kind of animal and several types of supernatural being. It is said in Tibetan Buddhism that it is very rare for a person to be reborn in the immediate next life as a human.
Psychiatrist Ian Stevenson, from the University of Virginia, investigated many reports of young children who claimed to remember a past life. He conducted more than 2,500 case studies over a period of 40 years and published twelve books, including Twenty Cases Suggestive of Reincarnation and Where Reincarnation and Biology Intersect. Stevenson methodically documented each child's statements and then identified the deceased person the child identified with, and verified the facts of the deceased person's life that matched the child's memory. He also matched birthmarks and birth defects to wounds and scars on the deceased, verified by medical records such as autopsy photographs, in Reincarnation and Biology.
The Bhagavad Gita states;
Hindus believe the self or soul (atman) repeatedly takes on a physical body.
Never was there a time when I did not exist, nor you, nor all these kings; nor in the future shall any of us cease to be. As the embodied soul continuously passes, in this body, from childhood to youth to old age, the soul similarly passes into another body at death. A sober person is not bewildered by such a change. (2: Protected content
Worn-out garments are shed by the body; Worn-out bodies are shed by the dweller within the body. New bodies are donned by the dweller, like garments.
In this 8-meter Protected content tall Buddhist relief, made sometime between the years Protected content 1249, Mara, Lord of Death and Desire, clutches a Wheel of Reincarnation which outlines the Buddhist cycle of reincarnation.
The early Buddhist texts make it clear that there is no permanent consciousness that moves from life to life. Gautama Buddha taught a distinct concept of rebirth constrained by the concepts of anattā, that there is no irreducible ātman or "self" tying these lives together (which serves as a contrast to Hinduism, where everything is connected, and in a sense, "everything is everything"), and anicca, that all compounded things are subject to dissolution, including all the components of the human person and personality.
In Buddhist doctrine the evolving consciousness (Pali: samvattanika-viññana) or stream of consciousness (Pali: viññana-sotam, Sanskrit: vijñāna-srotām, vijñāna-santāna, or citta-santāna) upon death (or "the dissolution of the aggregates" (P. khandhas, S. skandhas)), becomes one of the contributing causes for the arising of a new aggregation. At the death of one personality, a new one comes into being, much as the flame of a dying candle can serve to light the flame of another. The consciousness in the new person is neither identical to nor entirely different from that in the deceased but the two form a causal continuum or stream. Transmigration is the effect of karma (kamma) or volitional action. The basic cause is the abiding of consciousness in ignorance (Pali: avijja, Sanskrit: avidya): when ignorance is uprooted, rebirth ceases