I've maintained before that the claim in Socrates' defense concerning what sort of life is worth living is not simply an exhortation to a certain ideal; it is a therapeutic rejoinder to the morose conclusion of the tragic world view according to which "not to be born is best, and next best is to die soon." My contention is that Socrates actually concedes that the "worthwhileness" if life is not a foregone conclusion, but holds that there is a good life, and that its sine qua non is (in the usual translation, with which I won't quibble for now) "examination."
Nietzsche famously faulted Socrates for his diagnosis of life, most obviously in The Gay Science, 340: his account of the hemlock scene. He takes Socrates to task for (Nietzsche thinks) construing life as a disease one needs curing of; hence, Nietzsche thinks, Socrates' assertion that he owes a sacrifice of thanks to Asclepius. For all his polemics and his posturing as Anti-Christ, Nietzsche's first and last opponent is Socrates; and here, in his stance as an affirmer of life, he exhorts: "O my friends, we must overcome even the Greeks!"
So it is really quite something to remember that Nietzsche also names a sine qua non. This Yea-sayer, this prophet of amor fati, declares that there is after all one thing without which life would be, well, not worth living:
Without music, life would be a mistake.This is not an anomaly in Nietzsche, who engaged at the beginning and the end of his career with the most looming musical genius of his era; who at the end of his life signed his letters Dionysius, the god of that very art which his first book had said was born "out of the spirit of music." Nietzsche is probably the most musical of all modern philosophers, the one for whom music is most central to his thought, more so even than Schopenhauer before him, or Adorno or Marcel after. (His own compositions, despite the sneers they got from Wagner, still hold up.)
(Twilight of the Idols 33.)
A great deal depends upon how much difference one discerns between Nietzsche's sine qua non and Socrates'. For some, it's an open and shut case: they're diametrically opposed, 180 degrees apart! But others (and by no means the least Nietzschean) may say -- not "no difference at all!", but perhaps -- "180 degrees in what space?" For the space of reasons is not necessarily Euclidean. And neither is the space of music.