Pure Form or Not

Plato 有一個理論：he thinks we are living in the world of the shadow of Forms.

Which mean that everything has a pure form, everything we see only the shadow of the pure form. He used the example of we are sitting inside a dark cave beside us is a fire, and we only can see our shadow on the wall.

No matter what, this theory has an interesting assumption which is there exist of pure form, and this pure form is before the thing that existing. Is it very familiar that God creates man by using himself as a model?

However, Plato's student Aristotle, he has a total different point of view. Aristotle not believe in pure form before the thing. He thinks that form or pure form is the product of our experiences. We group the familiar/same things together and name it. So, whenever an animal, mammal, with four legs, barking we name it as dog. But you know no two dogs are exact the same, that's why we call German Shepard a dog, Golden Retriever a dog, they are the same but have same features, so we call it a dog.
Aristotle's theory refuses pure form exist before thing, and form is only a product of things together. At last, there is no "pure" as the definition of a form is changing whenever we gain more experience on that thing.

I don't know whether Aristotle believes in God or not. Although he does not believe in pure form, he has to find out why thing(s) exist.

If we follow the thought of Aristotle, I think we cannot find absolute good as there is no such a pure form of good. Without absolute good, what should a human to do in order to go to heaven?