The De anima and Self-Knowledge

That which Aristotle investigates systematically in the De anima he calls by the name ψυχή (psyche), that is, soul. This term appears among a rich vocabulary available to the earlier tradition for related notions. In the earliest Greek literature that we possess, Homer's epic poems, the psyche is a kind of breath-soul escaping at death, the eschatological soul flying off to Hades' realm and retaining there merely a pale, shadowy existence. This may help explain why ψυχή could also be used for butterfly or moth (see Aristotle HA 551a13–14). Heraclitus and Plato prominently accept psyche to stand for the whole soul (see, e.g., DK 22B36, B45, B77, B107, B115, B117, B118, and Plato Apology 29d–30b, Republic 353d, Cratylus 400a, Laws 959a). They perhaps delight in suggesting ironically that the afterlife need hardly be shadowy as Homer depicts it and that many persons now upon this earth lead merely shadowy lives.

But why suppose that there is soul at all? The ancients observe or postulate certain operations and functions; for example, animals engage in voluntary motions and have perceptive capacities, and humans seem perhaps to have some capacity for survival after death. Soul is then posited as necessary for explaining such functions as their source or cause. Only that account of soul suffices that manages to handle compellingly the function or functions that soul is introduced to explain.