what is with the letters benson?

Now, we all can pretty much define the difference between God and god. The capital G signifies a more individual presence or figure that is much more important and higher essence of being. Similarly as we spoke about in class the other day, the difference between being and Being. Well, in the Phenomenology of Prayer by Benson and Wirzba, they capitalize words like Impossible, God, Living, and I assume many more to come. This slightly confuses me, for example, on page nineteen "Relative to that possibility, what I may encounter is rather the Impossible." I am not sure of what significance this could mean. A specific impossibility? Something too superior to imagine? The blatant references to the Bible in this book relay the obvious definition they choose of the word God. However, Impossible? There are words following on page twenty, that are traditionally capitalizes in most Biblical situations such as, "Scriptures," "the Word," and "Trinity." These are in relation to specific pieces/beings that in certain beliefs are real and "truth." However, if someone could just aid me with any assistance on the other possible ways to understand a difference between these capitals, I would appreciate it!