I was reading that the platonic forms have the following principles
1. Commonality 2. Separation 3. Self-Predication 4. Purity 5. Uniqueness 6. Sublimity
But if there is a Platonic form of Existence (in the same way as beauty or the good) then the fourth principle says that this form is made up entirely of existence. But then all the other forms have the principle of purity to. So the form of Beauty contains only beauty and nothing from the form of existence. So it doesn't exist and neither do any of the other forms - which doesn't seem right.
What have I done wrong here. Where is my flaw in this reasoning?