the definition of soul is given as self-motion. Rocks, for instance, do not move unless something else moves them; inanimate, unliving objects are always said to behave this way. In contrast, living things are capable of moving themselves. Plato uses this observation to illustrate his famous doctrine that the soul is a self-mover: life is self-motion, and the soul brings life to a body by moving it. Meanwhile, in the recollection and affinity arguments, the connection with life is not explicated or used at all. These two arguments present the soul as a knower (i.e., a mind). This is most clear in the affinity argument, where the soul is said to be immortal in virtue of its affinity with the Forms that we observe in acts of cognition. It is not at all clear how these two roles of the soul are related to each other. But we observe this casual oscillation nevertheless throughout the dialogue and indeed throughout the whole corpus. For instance, consider this passage from Republic I:Is there any function of the soul that you could not accomplish with anything else, such as taking care of something (epimeleisthai), ruling, and deliberating, and other such things? Could we correctly assign these things to anything besides the soul, and say that they are characteristic (idia) of it? No, to nothing else. What about living? Will we deny that this is a function of the soul? That absolutely is.Throughout the 20th century, scholars universally recognized this as a flaw in Plato's theory of the soul, with this trend continuing and then ultimately being rejected in the 21st century. Here are some examples of what scholars have said about this puzzle: Sarah Broadie says that “readers of the Phaedo sometimes take Plato to task for confusing soul as mind or that which thinks, with soul as that which animates the body." Dorothea Frede argued that “as to the exact nature of the soul we are left somehow in the dark by Plato in the Phaedo and also in Republic X." D.R. Campbell argued that "Plato believes that the soul must be both the principle of motion and the subject of cognition because it moves things specifically by means of its thoughts." Legacy Plato's Phaedo had a significant readership throughout antiquity, and was commented on by a number of ancient philosophers, such as Harpocration of Argos, Porphyry, Iamblichus, Paterius, Plutarch of Athens,