I had a request to post more about Plato’s Forms. So, here you go, Jess!
Plato’s theory of Forms is a proto-theory of universals. What are universals? They’re characteristics that individual things share. The quality of being blue, blueness, for instance, isn’t an individual thing. It’s a characteristic shared by many individuals. Universals also include class concepts, like ‘cat’ or ‘dog’ or ‘tree’. We know that individual things exist, like Mona the cat, or Rex the dog, or my blue sweatshirt. But philosophers beginning with the ancients wondered about the nature of universals—catness, dogness, blueness—do they have some sort of existence of their own, part from the individuals? Because, here’s the thing, individuals come and go—Mona and Rex will die, and my blue sweatshirt will wear out—but the universals somehow remain the same. They seem to have a kind of timeless existence apart from individual physical things.
So Plato came up with his theory of Forms to explain the commonality between individual particular things. What do Rex, Fido, and Spot have in common? What makes them the same sort of thing? They “share in” or are “modeled after” the same Form. The Form stands outside all change, since it’s not physical. It’s timeless, perfect, immutable. Plato seemed to struggle with the exact relationship between forms and physical things (which we tend to call ‘particulars’). He used the language of “sharing in,” or being “modeled after,” and he also said that particulars “participate in” the forms.
As I said in the last post, Plato was particularly keen to explain how necessary knowledge was possible. As I noted, he recognized that things in the world around us are continually changing. You can never definitively say (in a timeless way) that a particular thing is a certain way. You can never say necessarily that it’s F (whatever the quality of F might be: blueness, beauty, tallness, slowness, etc.). Particulars are always both F and not-F. They always are both one way and its opposite, and for different reasons (though not at the same time and in the same regard). The main reason, though, is that particulars are always subject to time and change, so that whatever characteristic a particular thing has, wait long enough and at some point it will no longer have that quality. A painting might be beautiful now, but at some point it won’t be. So you can’t say definitively and for all time that it’s beautiful.
So Plato introduced The Forms as objects of necessary knowledge. When we know something absolutely, eternally, the thing we know must itself be absolute and eternal; it must stand outside all change, all time. Plato doesn’t normally talk about physical objects or about animals, etc.; in discussing the Forms, he usually talks about virtues such as Justice, Piety, or Goodness generally; or about qualities such as Beauty. (This is because of the influence of his great mentor, Socrates, whose whole philosophical concern was ethics.)
In sum, Forms are universals, and they’re the objects of necessary knowledge. We’re able to grasp them when we get away from sense perception of physical things and use our minds to contemplate the eternal, the unchanging. We venture out of the cave when we cease concerning ourselves with individual beautiful things and contemplate Beauty itself.
Plato’s Symposium depicts Socrates and some friends having a drinking party and giving speeches in honor of the god of love. (One of the most memorable passages in all of Plato’s works is Aristophanes’ discussion of original humanity as double beings who were split in half by Zeus, such that love is the desire to be reunited with one’s other half.)
Socrates’ speech describes how we all begin to appreciate beauty (which is the object of love): we desire a beautiful body. He then proceeds to describe how we progress to recognizing the beauty in many bodies, the beauty of the soul, the beauty of great works; and then ultimately we grasp Beauty itself in pure contemplation. So, in other words, love, our desire for beauty, begins with erotic attraction and ends in philosophy, which is the love of wisdom.
The Symposium contains one of Plato’s clearest depiction of The Forms, and it’s a brilliant piece of work, so if you’re interested in these issues, this would be a good place to start (definitely read the Nehamas/Woodruff translation).