Comment on Mantra 15 of Sri Isopanisad:
In many ways this mantra invokes the work of Paul Tillich. Tillich writes in his monumental Systematic Theology of God as a symbol. A symbol, however, is supposed to refer to something, but to what does the symbol of "God" refer? If we use Ockham's notion of first and second intention, we could say "God" refers to God, where the word picks out the concept. In other words, the written symbol "God" is a way of vocalizing the mental symbol of God. It seeks to know the God behind "God", but this mental symbol is not the ultimate concept of God, so you are left with eternally trying to find the God behind "God." We want to move past the infinite regress of symbolism and arrive at the Being of God. For Tillich, herein lies the problem.
Tillich argues that God is the answer to the question implied in Being.