Alcmaeon developed the first argument for the immortality of the soul, but the testimonia concerning it differ slightly from one another, and it appears to have been taken over and developed by Plato, so that it is very hard to determine exactly how to reconstruct Alcmaeon’s own argument. Barnes (1982, 116–120) and Hankinson (1998, 30–3) provide the most insightful analysis. Alcmaeon appears to have started from the assumption that the soul is always in motion. At one extreme we might suppose th