Reincarnation is a central tenet of several religions and philosophies, including Hinduism, Buddhism, Jainism, Sikhism, Shinto, and Theosophy. It is also found in some indigenous religions, such as those of the Native Americans and the Celts.
There are many different beliefs about what happens to the soul or spirit after death, and how reincarnation works. Some believe that the soul is reborn into a new body that is determined by their karma, or the sum of their actions in previous lives. Others believe that the soul is reborn into a new body that is chosen by God or a higher power. Still others believe that the soul is reborn into a new body that is simply the result of chance.
Reincarnation is a complex and multifaceted concept, and there is no one definitive answer to the question of what it is. However, it is a belief that has captured the imagination of many people, and has been a source of spiritual comfort and hope for millions of years.