It is an arbitrary, abstract thing. Its only interesting quality is that it can be present or absent. I'd settle for a thing that exists or doesn't exist, is here or not here, etc. I'm just after a single word to describe this thing.
closed as unclear what you're asking by user66974, Marv Mills, Edwin Ashworth, RegDwigнt♦ Apr 24 '15 at 11:12
Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.
As Sheldon Cooper would shout:
Being : the state or quality of having existence
Beingness : the state or fact of existing
Existence : the fact or state of existing
Existability : the possibility that something can exist
So the quality of Existing, or not Existing, is Existability.
The Existability of happiness in rocks is in the negative. [[Meaning : Rocks are devoid of happiness]]
The Existability of hardness in rocks is in the positive. [[Meaning : Rocks may or may not have the attribute of hardness. Some rocks are hard, while some are soft]]
So whether some quality can be present (or not) is expressed by Existability.