Plato’s images of the soul as described above as: a rational soul (intellect), the spirited soul (will) and the appetitive soul (emotional). From this three, he justifies that it is a disadvantage to oneself to be unjust since the three souls must perform/function in harmony for a common good as a whole.
The Allegory of the cave is a dialogue between Socrates (Plato's teacher) and Glaucon (Plato’s brother). It states, that in an area of what can be known, what is seen as the last thing though with effort, is the good; and upon being seen, it must be taken to be the cause for all things that are right and beautiful. It is an illustration of nature and man’s want of education. Plato used it to state a philosopher’s position in the real world by comparing him to one who has gone out of the cave and seen the real in its form.