I know the idea of different kinds of meanings seems abstract at first, but these different kinds of meanings are actually things we live with all the time. In addition, we are often very aware of the different kinds of meaning.

For example, if you were in a psychology class, and you had to do a statistical analysis of a certain population of people, you would probably have to provide a list of the participants, and some of their basic characteristics: "Sheila, Age 54, medical doctor, 2 children, non-smoker," that sort of thing. What if, instead, you wrote: "Sheila, Age 54, whose eyes are like limpid pools of azure, and whose hair shines like glistening wheat in the wind"? (Aside from getting your poetry license revoked, that is.) Wouldn't your professor wonder why you are being so "poetic" or "metaphorical," and why you don't stick to "the facts"?

Plato's Cave Allegory is an allegory, an extended metaphor. Each part of the allegory refers to something other than itself. For example, the prisoners represent human society (in its addiction to sensory appearances and opinions based on these appearances). However, if a word or concept does not refer to the actual thing it is supposed to refers, but to something else, isn't that an inaccurate word or concept? Or perhaps a lie?

On the other hand, don't non-literal forms of meaning - such as metaphor and allegory - help us in other ways? Can you think of some ways that non-literal forms of speech and thought are useful, or important, even though they are not factual?