What does Plato's allegory of the cave illustrate?

Plato’s allegory of the cave is primarily an illustration of the process of gaining knowledge. In Plato’s allegory the people are shown to make the step from a world of illusion towards intelligence.

To understand the allegory of the cave we may imagine a group of prisoners chained to face a cave wall. They have lived within this cave all their lives, for us it represents the world of sense experience. Behind these prisoners there is road and a fire. People walk past this fire, casting shadows onto the cave wall. These shadows are all the prisoners ever see. In this we may note that the shadows being perceived by the prisoners represent our own sense perception. The shadows give the prisoners a distorted view of these objects. In the same way Plato argues that our sense experience presents us with a distorted view of the true nature of reality. We are tapped within an illusion.

We may now consider one of the prisoners being set free and turned to face the road. Now the prisoner realises that his previous perception did not represent the true nature of reality. However, extending the allegory of the cave, the prisoner is now faced with a blinding light from the Sun. Having been in a cave his whole life this light is intensely painful and the prisoner must be dragged from the cave towards the true reality. This demonstrates what Plato viewed as the difficult process of acquiring knowledge. The light from the Sun effectively represents our prejudices and predispositions with regard to the nature of reality that must be overcome in order to gain knowledge of the forms (the objects beyond the cave), Plato’s most real and perfect objects. Once the difficult ascent from the cave has been achieved we can truly appreciate reality in its purest form.

In having a grasp now of the true nature of reality and in acquiring knowledge of the forms the prisoner must now make the descent back into the cave. This is because, Plato argued, that in making the ascent the prisoner is now a philosopher and with his knowledge he must help the other prisoners still trapped in the cave to free themselves or live out their lives by the principles of justice. The philosopher must become the philosopher ruler. However, the descent may not be easy. Those still in the cave will not have the knowledge he has and may treat him as a madman, Plato suggested they may even go as far as to kill him. This here represents the ignorant mob that the philosopher must rule. In lacking true understanding they may not understand the bitter medicine being administered by the philosopher ruler and reject what Plato would view as his wise judgement. Further to this, in being freed from the cave the philosopher may not wish to return. In the same way the real philosopher, having acquired knowledge of the forms may consider it undesirable to concern himself with the lives of the unruly mob.

In conclusion, Plato’s allegory of the cave represents the need for us to escape the illusory world of sense experience if we wish to acquire knowledge of the true nature of reality i.e. knowledge of the forms. The allegory of the cave demonstrates to us that this process is not meant to be easy but in doing so we free ourselves from illusion, although this freedom brings responsibility. The philosopher must return to the cave and dispense his wisdom for the benefit of the ignorant masses, a task that may be harder than the ascent from illusion itself.