A commonly studied topic in Philosophy is the study of the relationship between the internal and external body; that is to say, the distinction between the body and the soul. There are three basic ‘Theories of the Self. ‘ ‘Self=internal,’ ‘self=unity of internal and external,’ and ‘self as a material body. ‘ The first Theory of Self (‘self = internal’) is known as the dualist approach, the second (‘self = unity of internal and external’) is known as a psychosomatic or monist approach. Plato was a dualist.
That is to say he believed that every human being is made up of two substances: The physical body that belongs to the material world. It is through this body that we are able to experience and sense things, and thus form opinions. And the mind, which is a far superior thing that belongs to the ‘World of the Forms,’ it is through the mind that we can achieve true knowledge, rather than from the basic opinions that our physical bodies produce. These two components belong to two different worlds: The World of Appearances and the World of the Forms.
Since Plato thought less highly of the world of Appearances (as it symbolizes the limited world as described in his allegory of the cave), Plato believed that as the body was part of the World of Appearances, we should not be slaves to its urges. However, he emphasized that we should not abstain totally from the needs and urges of the body, but should not allow ourselves to become enslaved. Plato has many philosophical influences such as Socrates, Heraclitus, Permenides and Pythagoras.
We can see aspects of their ideas in his theories, particularly in relation to his teacher, Socrates. However, it is through the influence of Pythagoras, that Plato formed his ideas of the immortal soul. He put forward two basic arguments for the existence of an ever-lasting soul: The first relates to basic chemical theories that state that everything can be broken down into single elements. Now, as we know, the body is made of many different parts and therefore can be thought of as a perishable compound which can be broken down.
The soul, on the other hand, can be thought of as a single substance and can therefore can go on existing it it’s singular form for all eternity. The second simply points out that the soul if from the World of the Forms, which is eternal, and therefore must also be eternal. Plato also suggested that the soul exists before the body. This supports his central theory of anamnesis. We all have a soul that holds the key to true knowledge. All we must do is go through the process of anamnesis (remembering) to discover what we already know.
He described the soul as being imprisoned in the body until death, at which point it is liberated. However, Plato believed that the souls of different being were liberated to different places. The ‘pure’ souls of philosophers would be allowed to enter the eternal World of the Forms where it can regain its proper place in w world of true knowledge. The ‘impure’ souls (of the ordinary people) that have been content to live their lives in the ignorance and small minded World of Appearances will become ghosts, or inhabit the body of an animal etc.