Do all Buddhists believe in reincarnation?
Actually, the Buddha taught the doctrine of rebirth, not reincarnation, and this was one of the defining differences between his teachings and those of his contemporaries. Reincarnation implies the migration of a soul, an intrinsic impermeable self, from one physical form to another. Buddhism teaches that there is no irreducible self, but instead a constantly changing set of mental and physical components called the five aggregates or skandhas. Buddhist practice, particularly meditation, is meant to help us realize the nature of the skandhas, thus freeing us from the delusion of self and cycle of rebirth.