His analogy of the cave is the premise in which he chooses to emphasise this difference between the appearance of the world and the reality behind this appearance. Different characters and objects represent different things. The prisoners represent the ordinary people who have not yet discovered true knowledge. Their idea of reality does not go past what they see (appearances). The cave that they had been chained up in for all their lives represents the visible world. During the analogy the prisoners see shadows on the walls of the cave that represent the illusion created by our senses. The analogy then contrasts to the philosopher’s journey out of the cave and into the outside world which represents his discovery of true knowledge. Once he is outside the cave he can see the sun. It is the most perfect of all realities- The Form of the Good. His return to the cave shows that his quest for true knowledge is complete. He tries to enlighten the other prisoners but is ridiculed. Plato’s analogy is the illustration of his theory of forms.
Now that we have seen Plato’s theory of the world and its forms I will evaluate his ideas and explain the reasons why his theory does not work.
The first reason which disproves Plato’s theory was that his analogy was based on an assumption. He thought that anybody who had discovered true knowledge would never return to the empirical world, basically meaning that if someone knew the truth then they would live by it. This is Plato’s own ideology; it is not that of the majority of people.
Following on from my previous point is people’s acceptance of empirical knowledge. The majority view is that physical existence is real, so therefore nothing can be more real than something being there in front of you, i.e. something that is real and tangible. Plato’s idea that there is something behind all objects and concepts is unjustifiable as something must be seen or experienced to make it worthy of believing in. The fact that it is his view that the forms are immutable does not make them more real. This is also the case for the world of forms being more perfect than an already perfect visible world. This is not possible as you cannot have something being more perfect than something else which has already achieved the height of perfection.. Perfect is the highest form goodness and quality.
Furthermore the cave in his analogy does not represent the sheer attractiveness and beauty of the visible world. It paints a grim picture which then of course shows the world of reality to be mesmerising. Therefore the actualities are not depicted in Plato’s analogy just so that he can show the world of forms to be the true source of enlightenment.
Another flaw of the analogy is that it fails to illustrate the differences between the world of forms and the visible world. Plato’s belief was that the two worlds were completely different. However he presented them to be very similar in his analogy, for example the sun and the form of the good, being reality, and the form of shadows and fire, being appearances. He could not successfully illustrate that the two worlds were fundamentally different and therefore this is yet another reason for his forms being no more than an invention.
Finally and most importantly Plato has no evidence for any of his theories and ideas. He even realised this but says that physical evidence is not required. In effect he is saying that his ideas are non-sensical as they cannot be proved or disproved.
So, as one can see there are many reasons why Plato’s forms lack substance. They are no more than Plato’s own ideology as there is no evidence that there is any such thing as forms of real concepts and objects. Therefore his ideas cannot be proved. This can only lead us to the conclusion that Plato’s forms are no more than an invention.