Beauty is an argument for the existence of god. For example "How can you look at all the beautiful things in the world and not believe in a god?". A counter argument is to just ask the same but with something ugly, for example: "How can you look at a bubonic plague victim and believe in a god? A counter-apologist might also reply "Who are you to assume you and God have the same taste in interior decorating?"
A more proper name for the argument would be the "Argument from Aesthetics."