Who Is Nietzsche's Zarathustra?

As for the first subterfuge, according to which Nietzsche's thought of eternal recurrence of the same is a mystic phantasmagoria, a look at the present age might well teach us a different lesson—presupposing of course that thinking is called upon to bring to light the essence of modern technology.

What else is the essence of the modern power-driven machine than one offshoot of the eternal recurrence of the same? But the essence of such machines is neither something machine-like nor anything mechanical. Just as little can Nietzsche's thought of eternal recurrence of the same be interpreted in a mechanical sense.

That Nietzsche interpreted and experienced his most abysmal thought in terms of the Dionysian only speaks for the fact that he still thought it metaphysically, and had to think it solely in this way. Yet it says nothing against the fact that this most abysmal thought conceals something unthought, something which at the same time remains a sealed door to metaphysical thinking.

(See the lecture course "What Calls for Thinking?" taught during the winter semester of 1951-52 and published in book form by Max Niemeyer, Tübingen, in 1954.*)

* Translated by Fred D. Wieck and J. Glenn Gray as What Is Called Thinking? in 1968 for the Harper & Row Heidegger Series.

Martin Heidegger (GA 7) Who Is Nietzsche's Zarathustra? - Nietzsche 2