Gigi asked:
I have a writing assignment in my philosophy class and one of the sections is to:
Explain how Plato’s epistemological assumptions shape his metaphysics.
I have read the material on the allegory of the cave and the Republic and I’m still struggling with how to write this part.
The professor gave us a hint which is: Why does he think that there must be Forms? Plato says (in effect),
‘Since knowledge is ____
therefore the objects of knowledge must be _____.’
Any advice would be greatly appreciated.
Answer by Jürgen Lawrenz
I’m not going to write your assignment for you, but really, the issue is very simple.
Everything in the world is imperfect. Water drops might form neat little spheres, but every water drop is different from every other.
In a field of clover, they all look the same; but when you inspect them from close up, there is minute variation everywhere.
However, you could say: we KNOW what a sphere, a clover, or a tiger or herring looks like, because they are individual specimens of a TYPE.
This is where we form a judgement that all individuals must belong to some pattern of FORM. Accordingly when we see such a pattern or form in nature, we recognise it, even though in many detail it differs from the last specimen we saw. We then go ahead and establish, say, a taxonomy: certain kinds of animals are cats because they share cat-like features. And so on. In other words: We create an IDEA in our minds about a species of some animal or thing.
Plato believed that such IDEAS are eternal. In our language, he might have said: they are the thoughts in a creator’s mind. The creator might say to himself: I have an idea for a tiger and now I will create living examples of the idea. The idea in God’s mind would be of one perfect specimen, which in the real world of sexual reproduction is not, of course, going to be reproduced identically in every detail.
So our KNOWLEDGE of things depends on having a true IDEA in our mind.
The parable of the cave is an exaggerated way of saying: in this world, the world we live in, we are trapped by our senses, which cannot capture the essence of the form in any actual thing. Our sense must make judgements about the imperfect specimen before our eyes. If not, they might bite!
But if you ponder the form you see philosophically, then you will understand the essence of that form.
Is that clear now?
Ask a Philosopher 
Perfect! This is exactly the explanation i was looking for. I wonder if we have the same teacher because I have the exact same prompt “)