Plato's theory of soul
Plato's theory of soul, which was inspired by the teachings of Socrates, considered the psyche () to be the essence of a person, being that which decides how people behave. Plato considered this essence to be an incorporeal, eternal occupant of a person's being. Plato said that even after death, the soul exists and is able to think. He believed that as bodies die, the soul is continually reborn (metempsychosis) in subsequent bodies. Plato divided the soul into three parts: the logistikon (reason), the thymoeides (spirit, which houses anger, as well as other emotions), and the epithymetikon (appetite or desire, which houses the desire for physical pleasures). The conception of the soul Plato was the first person in the history of philosophy to believe that the soul was both the source of life and the mind. In Plato's dialogues, we find the soul playing many disparate roles. Among other things, Plato believes that the soul is what gives life to the body (which was articulated most of all in the Laws and Phaedrus) in terms of self-motion: to be alive is to be capable of moving yourself; the soul is a self-mover. He also thinks that the soul is the bearer of moral properties (i.e., when I am virtuous, it is my soul that is virtuous as opposed to, say, my body). The soul is also the mind: it is that which thinks in us. We see this casual oscillation between different roles of the soul in many dialogues. First of all, in the Republic: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.The Phaedo most famously caused problems to scholars who were trying to make sense of this aspect of Plato's theory of the soul. Accordingly, the Phaedo presents a real challenge to commentators through the way that Plato oscillates between different conceptions of the soul. In the cyclical and Form-of-life arguments, for instance, the soul is presented as something connected with life, where, in particular in the final argument, this connection is spelled out concretely by means of the soul's conceptual connection with life. This connection is further developed in the Phaedrus and Laws where 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