God is so quiet

[SteveII]

Fine, I will grant that the concept of existence must be present in every possible world and that concept is something (much like numbers, logic, and other abstract objects). However, this whole discussion started when I made the statement that the universe does not necessary exist. That is still the case.

Are you saying all things abstract (such as mathematical truths) are situated beyond the universe/cosmos? That space-time is situated somewhere beyond the universe/cosmos?

Not at all. You are missing what "possible world" semantics means. A "possible world" is the way reality could have been. While the actual world is a possible world, all the rest of them are just conceptions used to iron out logical questions. If you are going to discuss philosophy and metaphysics, you MUST become acquainted and know how to use the terms. Read this if you need to: https://en.wikipedia.org/wiki/Possible_world

To be clear, there is only one actual world--the one we see.