You seem to believe in an ontological reality to greatness. A lot of atheists see greatness as a perception and a subjective value rather then an actual property of reality or a being.
If you believe it's an actually property, I offer the following argument.
All possible levels and instances of greatness require a basis.
The only possible basis to all possible levels and instance of greatness is ultimate greatness.
Greatness exists in reality and is not simply a matter of subjective perception.
Therefore ultimate greatness exists.
If you believe it's an actually property, I offer the following argument.
All possible levels and instances of greatness require a basis.
The only possible basis to all possible levels and instance of greatness is ultimate greatness.
Greatness exists in reality and is not simply a matter of subjective perception.
Therefore ultimate greatness exists.