Comment by flenserboy

It does bring that to mind, especially given the era he came out of. Likely, however, what he is trying to get at is the distinction between God/not God: existence is something a thing which is not God — a neutrino, a squirrel, a rock — is given, which makes speaking of God as having existence in the same way as those things a mistake, as if the highest thing is just one of those many things which could be enumerated that way. This helps maintain the distinction Tillich is likely aiming at, which is to avoid speaking of God as part of the universe, or in some panentheistic way.