The number of human beings admits neither of increase nor of decrease, and a regular process of metempsychosis goes on continually.
He was credited with having originated the doctrine of metempsychosis, while Cicero and Augustine assert that he was the first to teach the immortality of the soul.
Moses and Paul are put side by side with Aristotle and Menander, and there is a clear inclination to Platonic doctrines of preexistence and metempsychosis.
The doctrine of metempsychosis seems to have been familiar in early Ireland.
They are said to have had a firm belief in the immortality of the soul and in metempsychosis, a fact which led several ancient writers to conclude that they had been influenced by the teaching of the Greek philosopher Pythagoras.