There is the rational part of the soul which helps the person see and make the obvious decisions, and then there is the appetitive part which is the part that controls the desire to want something even though it could be bad. Last there is the spirited part of the soul which is competitive and experiences anger and shame (pomerleau, 14). These three parts are very different yet inseparable parts of the soul. Plato states that there is a direct order to these parts as well. The reason should rule and spirit should be its ally in controlling the dangerous, self-indulgent inclinations and desires of the appetites (pomerleau, 14). Aristotle begins by telling us that the souled is distinguished from the unsouled by being alive. He also says that all living things have souls. .
Aristotle's theory discusses that there are different types of souls, not different parts. There is the vegtitative soul of plant life which has control of nutrition and growth and reproduction, the second is the sensitive soul which has all of that the vegetative soul has and also senses including internal and external senses. Last is the rational soul, which has all of the above and intellect and thought, and the ability to make free choices. This is the highest type of soul. These different types of souls are on somewhat of a hierarchy level which Aristotle refers to as more primitive souls. For example a dog is more capable of things then a bush is because it has a higher level of soul, and a human person is more capable then a dog because human persons have the highest level of soul.
As I talked about a little earlier in my paper Aristotle believed that a body cannot be a body without the soul, and a soul cannot be a soul without the body. To delve into this Aristotle believed that any organ is not an organ without the sense that goes with it. For example an eye is only an eye when it has the power of sight, without the sense of sight an eye is just matter taking up space.