He believed that the forms were interconnected and arranged in a hierarchy. He believed that the most important Form is the Form of the Good, which is the principle. The Good illuminates the other Forms like the sun in the Allegory of the Cave. The sun also represents knowledge and energy, which the world needs to live on in order to complete the seven life processes. We can see that justice for example is an aspect of Goodness and we know that we have never seen with our senses any examples of perfect goodness, but we have plenty of particular examples which approximate goodness and we know that they are ‘good’ when we see them because of the way in which they correspond to our innate notion of the Form of the Good. Using Plato’s logic, real knowledge becomes knowledge of goodness in the end and this is why philosophers are in the best position to rule.
Plato is an example of a rationalist. He says that sense experience fails to provide us with any guarantee that what we experience is, in fact, true. The information we get by relying on sense experience is constantly changing and often unreliable. It can be corrected and evaluated for dependability only by appealing to principles that themselves do not change. These unchanging principles or "Forms" are the bases of what it means to think or reason in the first place. So if we can show that an opinion or belief we have is based on these undoubtable principles of thought, we have a firm foundation for the opinion. That foundation is what allows us to think of a belief as more than simply opinion; it is what allows us to identify the belief as justified and true, and that is what is meant by knowledge. Plato splits up existence into two realms: the material realm and the transcendent realm of forms. The world of changing, material objects (the visible world) is merely a fleeting image of the intelligible world--what Plato calls the realm of the Forms. Physical objects are real only insofar as they are intelligible, but they can be intelligible only in terms of that which does not change. What makes a thing intelligible as a certain kind of thing cannot be constantly changing: otherwise, it could not be identified as that kind of thing, nor would it be that kind of thing. So a thing is what it is in virtue of something that is not changing. But since the visible world is constantly changing, it cannot be used as the basis for identifying what things are. There must be an intelligible (non-sensual) realm in terms of which physical things are said to exist intelligibly. That is the realm of the Forms.
Plato realises that the general run of humankind can think, and speak, etc., without any awareness of his realm of Forms. In the allegory, Plato likens people untutored in the Theory of Forms to prisoners chained in a cave, unable to turn their heads. All they can see is the wall of the cave. Behind them burns a fire. Between the fire and the prisoners there is a parapet, along which puppeteers can walk. The puppeteers, who are behind the prisoners, hold up puppets that cast shadows on the wall of the cave. The prisoners are unable to see these puppets, the real objects, that pass behind them. What the prisoners see and hear are shadows and echoes cast by objects that they do not see. Such prisoners would mistake appearance for reality. They would think the things they see on the wall (the shadows) were real; they would know nothing of the real causes of the shadows. If a prisoner says "That's a book" he thinks that the word "book" refers to the very thing he is looking at. But he would be wrong. He's only looking at a shadow. The real referent of the word "book" he cannot see. To see it, he would have to turn his head around. Plato's point: the general terms of our language are not "names" of the physical objects that we can see. They are actually names of things that we cannot see, things that we can only grasp with the mind. The prisoners may learn what a book is by their experience with shadows of books. But they would be mistaken if they thought that the word "book" refers to something that any of them has ever seen. Likewise, we may acquire concepts by our perceptual experience of physical objects. But we would be mistaken if we thought that the concepts that we grasp were on the same level as the things we perceive.
Plato's simile of the sun, image of the divided line, and allegory of the cave are intended to clarify exactly how the things we experience in the sensible, ordinary world (e.g., chairs, drawn triangles) are less real than the ideal models (Forms) on which they rely for their existence and in terms of which they are intelligible. Just as drawings, reflections, or copies of sensible objects are not as real as the sensible things on which they depend, so sensible things are not as real as the concepts in terms of which they are identifiable. Humans have access to the realm of forms through the mind, through reason, given Plato's theory of the subdivisions of the human soul. This gives them access to an unchanging world, invulnerable to the pains and changes of the material world. By detaching ourselves from the material world and our bodies and developing our ability to concern ourselves with the forms, we find a value, which is not open to change, or disintegration. This solves the first, ethical, problem. Splitting existence up into two realms also solves the problem of permanence and change. We perceive a different world, with different objects, through our mind than we do through the senses. It is the material world, perceived through the senses, that is changing. It is the realm of forms, perceived through the mind, that is permanent and immutable. It is this world that is more real; the world of change is merely an imperfect image of this world.
Plato developed his Theory of Forms to the point where he divided existence into two realms. There is the world of sense experience, where nothing ever stays the same and beings are mortal, it is always in the process of change. It is the world, which we live in. There is also a world, which is outside space, and time, which is not perceived through the senses and everything is permanent and perfect or ideal, this is known as the ‘realm of the forms’ and this is supposedly where our souls go after our body dies. The empirical world shows only shadows and poor copies of these forms, and is therefore less real than the world of the form themselves, because the Forms are eternal and immutable, the proper objects of knowledge.
1b. This theory is convincing because it shows people in society that they cannot judge what is beautiful and shows the media that although they show many beautiful people to advertise, no one knows the perfect form of beauty, and have just been told what beauty is, but have not actually experienced it and have never seen a perfect example of it. Christians now believe that the world is not the only world and that there is another realm where we will live eternally after death, which relieves people who are scared about death. The concept of the Form of the Good has helped to shape the way in which Christians understand God, as a perfect being, beyond space and time, eternal and unchanging, the source of all goodness and the proper focus of all thought and pursuits. The theory is not very convincing as the realm of the forms is meant to be the perfect world, but Plato said that we do not know what perfection is and that things are just reflections of it, so therefore how do we know what a perfect world is? His thought is very complex and it works on many different levels. It interrelates and his ideas change as he challenges his own beliefs and follows his own quest for knowledge. Many people did not accept many of his conclusions as they thought that his Form is not necessarily the obvious conclusion of logical reasoning or the only conclusion. He does not provide any convincing argument in favour of the belief that there is a realm of ideas, more real than the world of appearances. We agree that we need to have concepts of perfect equality, or perfect circularity or even perfect goodness to understand the world but this doesn’t mean that they have to have an independent existence. Any more than language has any sort of independent reality beyond the world which it refers to. This higher level of reality in the realm of the forms according to Plato is self-evident. It is not self-evident to us as the appearance of a wall or a parking meter is real enough when you accidentally walk into one, whereas the Ideal Form of the Dog does not seem to have much reality even as a concept. What colour is the Dog? Does it have a thick coat? Some concepts fit Plato’s system of thinking better than others, such as the mathematical ones do. It is also difficult to imagine an Ideal Form of something unpleasant such as Dirt or Disease, or even something ordinary such as bus tickets. He is also not very clear about how far the Forms relate to specific items in the ‘world of appearances’ for example do humans or animals have an ideal form that we can relate? Or do forms have to relate to specific humans or animals? Is there a form of pig or a separate form of each variety of pig? The forms stop being ‘universals’ and degenerate into something, which has little meaning or use. Plato’s ideas about the immortality of the soul are dependent on our acceptance of his other ideas about the existence of Forms and about knowledge being recollection or re-cognition of things we already know. People might not accept Plato’s view that knowledge gained through sense experience is not valuable, even if it is temporary.
Plato also believes that the highest of all forms of knowledge is an understanding of the Form of the Good, which he holds to be an absolute. This raises many of the problems such as how are we to know goodness is? How can two people, equally intelligent and equally sincere come to completely different conclusions about right and wrong? Plato appears to hold that the Form of the Good keeps in existence the whole world of forms and appearances too, just as the sun gives light and casts shadows, but we will all point at the same sun if were asked, whereas we cannot agree about what true Goodness is and how it should be shown to other people. Each argument is connected to a function Plato has in mind for Forms to play. ‘Forms are objects corresponding to Socratic definitions,’ provides an objective basis for moral concepts. A definition is correct just in case it accurately describes a Form. The definition of Justice for e.g. is that statement, which correctly tells us what justice is. ‘Forms are objects of recollection.’ Tells us that knowledge we get when we are in possession of a Socratic definition is a priori, not empirical. So Forms are the entities for such a priori truths to be about. The “imperfection” argument shows us that forms are the real entities to which the objects of our sensory experience correspond. We make judgements about such properties as equal, circular, square etc. Even though we have never actually experienced any of them in perception. Forms are the entities that perfectly embody these characteristics we have in mind even though we have never experienced them perceptually. His ‘Argument from knowledge’ makes us question what is our knowledge “about”? when we know something, what Is our knowledge of? Plato supposes that there is a class of stable, permanent, and unchanging objects that warrant our knowledge claims. There is also a “One Over Many” argument where a famous passage in the Republic suggests a semantic role for the Forms. That is, when you use the word ‘just’ and I use the word ‘just’, what makes it one and the same thing that we’re talking about? Plato’s answer is: the Form of Justice, the “one over the many.” A non-conventionalist answer to questions of meaning: there is some thing that is referred to by ‘just’ whenever it is used. Hence, when you talk about justice and I talk about justice, we are talking about the same thing. We belong to the same world, not each of us in his own private world. If we disagree in what we apply the term ‘just’ to, we cannot both be right.
Plato ends up using the theory of the soul that he also proposes in the Phaedrus. The soul, on this view, has three parts, which correspond to three different kinds of interests, three kinds of virtues, three kinds of personalities- depending on which part of the soul is dominant, and so, properly, to three kinds of social classes that should be based on the three personalities, interests and virtues. Plato believes that our experience of the Form pre-dates our experience of the “real” object. Aristotle, Plato’s pupil, was critical of this idea and believed that the “Form” is developed through continued experience of physical things.
In Plato’s later works, like the Parmenides, Plato seems more open to the difficulties and criticisms of his theory of the Forms. Despite the obvious problems with the theory, the main point is an important one: is it possible to really know anything? At the time Plato was writing there was a group of itinerant philosophers called Sophists who believed that knowledge is relative: what matters is not what is true, but what you can be persuaded to believe. For Plato such relativism was dangerous and he set out to show that is possible to have knowledge of things. The question of what can we know continues to be a central issue of debate in philosophy. Plato’s philosophy forces us to consider such questions, and it was Plato’s main concern that too many people simply cannot be bothered to think for themselves or to question their beliefs.