I'm not sure Faust chooses not to decide. Rather, he places a condition on the Devil's triumph. ONLY if he (Faust) utters certain words - "Stay a while, you are so sweet" is one variation - will the Devil win, and claim Faust's soul. So it's not so much an either/or, as much as a unique twist on the theme. ("The Devil and Daniel Webster" explores that theme from another aspect, that of a lawyer matching wits with Satan. At stake - the soul of Mr. Webster's client).
At any rate, the theme of beauty runs through Goethe's play in the form of temptation. Will Faust find anything so compellingly beautiful as to make him lose his bet? Dr. Bill says the idea of the building of the Panama Canal, of all things, proves to be Faust's undoing. There's that reference again to the question Faust poses to the Devil: "When did the likes of you ever understand a human soul in its supreme endeavor?" After presenting to Faust all manner of temptation in an effort to make him wish the moment would stay, can the Devil understand this passion to control and manipulate the very geography of the Earth?
As Dr. Bill asked in his original post on another thread, what would you find beautiful enough to make you lose your bet with the Devil?
