Sangpotshi, sometimes called the River of Life, is a philosophy practised almost universally in Tian Xia. It proposes that karma and fate are what determine a soul's position at the time of birth: deeds performed in a past life influence the class and quality of life into which the soul is next born. This form of reincarnation might continue through many lifetimes for a soul until, finally, the soul is able to move on to its final resting place in the Great Beyond. This belief in Tian Xia is closely tied to the political philosophy of divine right, which states that rulers derive their political legitimacy from being appointed by the gods.
Paizo published an article about Sangpotshi in Disciple's Doctrine 22f.