Peter Kreeft summarizes his version of the aesthetic argument like this:
1. There is the music of Bach.
2. Therefore, God exists.
Kreeft concludes, "You either see that one or you don't." However, I think there's a lot to be said about this argument. A beautiful song, such as "Jesu, Joy of Man's Desiring," must have been composed by an ingenious mind. Suppose that we focus instead on the wonders of nature. The orderliness of nature is awe-inspiring and, quite frankly, beautiful. Based on nature's beauty, we are justified in inferring the existence of a cosmic "composer," or designer.