Yet Platonic tripartition is also central to Galen’s physiology of the whole body. The three parts—rational, spirited, desiderative—correspond to and are located in, respectively, the brain, the heart and the liver. These are the central organs in Galen’s physiology, responsible respectively for: rational thought, perception and voluntary motion; involuntary motions (especially pulse and respiration) necessary to the maintenance of life; and blood-production and nutrition. Galen’s adaptation of the Platonic tripartite soul theory is strikingly original and intellectually ambitious. (He finds explicit textual justification for these bodily locations of the soul parts in a passage from Plato’s Timaeus—although that text is primarily concerned to give an ethically normative account of the internal balance of the soul, not to advance a serious or detailed physiology.)