What does it mean to exist? So, existence in a physical universe depends on circular logic. — TheMadFool
Several of you have made this point and I'm beginning to agree.
"Existence means something is or has being" is circular. There's no way around it.
"Existence is when something participates in existence" is also circular, but I like it. There's no way to arrive an a more fundamental understanding of being. I like participation though because it's ontologically top down rather than bottom up.
A top down approach is helpful in general about being. I was driving in the morning and was caught by the blinding light of the sun. You have to look away or you'll crash or go blind. Maybe theologians, Kabbalists, and occultists and so on are all sun starers. They attempt to look directly at the Absolute and think they see Forms or Emanations or a Trinity (or not) or even a whole pantheon. They practice Cataphatic theology, God is this, God is that. Really the shapes they think they are seeing within the Godhead are the burning holes in their retinas!
I think it's okay to be a Christian and believe in the trinity, for example. The Catholics are right, it's a mystery. But what's not okay is claiming that you authoritatively know or to condemn those with a different view. So I can be a Platonist and roll with the Forms, for now, it's an concept that is useful. In the end though I know I'm probably wrong!