Pythagoras and the Soul That Moves Between Bodies

Metempsychosis, from Greek roots meaning to change ensoulment, names the doctrine that a soul survives bodily death and is reborn into a new body, human or animal, in a repeating cycle. The doctrine enters Greek philosophy through Pythagoras in the sixth century BCE, and ancient sources, including Xenophanes' mocking anecdote of Pythagoras recognizing a dead friend's voice in a beaten dog and asking that it be spared, treat the claim of remembered past lives as a distinguishing, controversial feature of the Pythagorean school from its beginning.

The Orphic religious movement, roughly contemporary with or slightly earlier than Pythagoreanism and closely intertwined with it, held a related doctrine, that the soul is imprisoned in the body as a punishment or a cycle to be escaped through ritual purity and initiation, giving metempsychosis in its Greek form an ethical and soteriological charge beyond simple survival after death. Both traditions treated the cycle as something to be ended rather than affirmed indefinitely, an early and influential instance of transmigration understood as a problem awaiting release rather than a neutral fact about the soul. No writing by Pythagoras himself survives, so everything known of his teaching on the soul comes through later reporters, which is part of why ancient and modern accounts of the doctrine's exact content differ.