Plato’s Theory of Ideas or Forms

“The man who loves only beautiful things is dreaming, whereas the man who knows absolute beauty is wide awake.”


Let’s begin it this way-

Plato’s philosophy rests on the distinction between reality and appearance. This is certainly due to the influence of the logic of Parmenides and the other-worldliness of Pythagoras.

Portrait of Plato

In Platonic understanding, a person who only sees beautiful things has mere beliefs or opinions, whereas a person who sees beauty in itself has knowledge. The man who who loves only beautiful things is dreaming, whereas the man who knows absolute beauty is wide awake.

Here, we must note what Plato talks about the philosopher- the person who loves the ‘vision of truth’. According to Plato, a philosopher is the one who sees the beauty and has knowledge.

A brief differentiation between knowledge and opinion is necessary here. Plato gave it this way-

Opinion is of the world presented to the senses, whereas knowledge is of a super-sensible eternal world. For instance, opinion is concerned with particular beautiful things and is not real, but knowledge is concerned with beauty in itself and is the only reality. This will be understood more clearly in Plato’s theory of ideas or forms (analysed below).

Plato’s Theory of Ideas or Forms

Plato’s theory of ideas is partly logical and partly metaphysical.

The logical part has to do with the meaning of general words. When we use the word cat to refer to an animal, it is different from each particular cat. If the word cat means anything, it means something which is not this or that cat, but some kind of universal cattiness (that of being a cat). This is not born when a particular cat is born, and does not die when it dies. In fact, it has no position in space and time- it is eternal.

Let’s see the metaphysical part of Plato’s theory. Here, the word cat means certain ideal cat, the cat created by God, and unique. Particular cats are the copies or the shadows of the nature of the cat. The particular cats are imperfect and it is only owing to this imperfection that there can be many of them. The ideal cat is real; particular cats are only apparent.

Plato’s theory of ideas or forms can be more clearly understood by looking at the following example given by Plato himself.

Look at the picture first:

A model of a bed.

Plato explains that whenever a number of individuals have a common name, they also have a common idea or form. For instance, though there are many beds, there is only one idea or form of a bed. Just as a reflection of a bed in a mirror is only apparent and not real, so the various particular beds are unreal, being only copies of the idea, which is the one real bed, and is made by God. Of this one real bed, made by God, there can be knowledge, but in respect of the many beds made by carpenters, there can be only opinion.

In short, what we see are not real, they are copies of the ideal or form. A red rose you see in a garden is actually a copy of the idea or form of the red rose. The real red rose is somewhere else which can be known to those who seek true knowledge.

Plato would say that the philosopher will be interested only in the one ideal red rose, not in the many red roses found in the sensible world.

What we have been made to understand so far is that there is a world of ideas other than the world of senses that we are familiar with. Why would Plato create this world of ideas in his theory is really interesting. Let’s find out the necessity of the world of ideas in Plato’s theory.

According to Plato, there are two kinds of intellect- reason and understanding. Of these, reason is the higher intellect- it is concerned with higher ideas and its method is dialectic. Understanding is the kind of intellect that is used in mathematics; it is inferior to reason since it uses hypotheses which it cannot test. Take the example of the straight line. There are no straight lines in the sensible world. There is a need for finding evidence for the existence of super-straight lines in a super-sensible world. This cannot be done by understanding; it can be done by reason, which shows that there is such a line in heaven.

Plato seeks to explain the difference between clear intellectual vision and the confused vision of sense-perception by an analogy from the sense of sight. Sight differs from other senses since it requires not only the eye and the object, but also light. We see clearly objects on which the sun shines. In twilight, we see confusedly, and in darkness, not at all. Plato says that the world of ideas is what we see when the object is illuminated by the sun, while the world of passing-things is a confused twilight world. The eye is compared to the soul, and the sun as the source of light to truth or goodness.

The above analogy leads to Plato’s famous allegory of the cave. A very good illustration of the allegory of the cave is provided here:

An illustration of the allegory of the cave. Source

Now let’s see what the allegory of the cave is saying:

Those who does not know philosophy are like prisoners in a cave. These people are only able to look in one direction because they are bound, and they have a fire behind them and a wall in front. Between them and the wall, there is nothing. All that they see are shadows of themselves, and of objects behind them, cast on the wall by the light of the fire. Inevitably, they regard these shadows as real and don not know the real objects as they are actually. At last, some man succeeds in escaping from the cave to the light of the sun. For the first time, he sees real things, and becomes aware that he had hitherto been deceived by shadows. If he is the sort of philosopher who is fit to become a guardian, he would go back into the cave and tell others the truth that what they have been thinking so far as real things are just shadows. He will show them the way up. But, others inside the cave would think that he is stupid and would not listen to him.

All these discussions have led to Plato’s the idea of good. For Plato, reality, as opposed to appearance, is completely and perfectly good. To perceive the good, therefore, is to perceive reality.

The world of ideas, thus is necessary for us to come out of the shadows and know the truth, the reality.

However, Plato’s theory of ideas or forms is subject to certain criticisms. It is argued that Plato fails to realise how great is the gap between universals (world of ideas) and particulars (world of senses). His ideas are really just other particulars, ethically and aesthetically superior to the ordinary kind. Besides, if appearance really appears, it is not nothing, and is therefore part of reality.

On the other hand, creation of a timeless thing can also be questioned. It is difficult to see how God can have created the ideal bed, since its being is timeless. What is timeless must be uncreated.

Nevertheless, the theory of ideas cannot be wholly abandoned. As Socrates says:

Without ideas, there will be nothing on which the mind can rest, and therefore reasoning will be destroyed.


Reference: Bertrand Russell, History of Western Philosophy.

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