All beings ceaselessly move in the alternation of birth and death, like the turning of a wheel. The notion of the “turning of the wheel,” i.e., reincarnation, assumes that the soul does not follow the ruin and disappearance of the body. That is why it can ceaselessly return and be received in a new body in the alternation of life and death. In India before the birth of Buddhism, reincarnation was already a popular concept. Because in the reincarnation an individual must passively undergo the results of the actions of previous lives, the process is generally considered to be painful. The fundamental rationale of Buddhist thought is to understand the process of life, of going and returning in this cycle, an endless, continuous array of cause and effect. It furthermore emphasizes that by eliminating causes one can reach the goal of eliminating results and finally stop the “reincarnation,” thus being liberated from this suffering.

In the endless cycle of birth and death, beings are blinded by ignorance and bounded by the tie of craving. The wheel turns nonstop and one does not know the real cause of suffering. (Miscellaneous Canonical Texts)