Just as one who believes in reincarnation does not need a physical demonstration of it, Nietzsche’s theory of eternal recurrence does not need a physical demonstration.
In a later chapter of the same lecture, “Regressive Thought as Faith,” Heidegger quotes about six passages in Nietzsche’s posthumous writings in which Nietzsche himself calls the theory of eternal recurrence “faith” and describes a person who “does not believe” in the theory of eternal regression, etc., and then says
After all, the thought of this idea is the kind of thing that Nietzsche could, and not only could, but must, call a “faith.
Heidegger, however, adds a caveat to the word “faith,” stating: “Nietzsche is not a ‘faith’ in the following sense.
Nietzsche characterizes the essence of faith in these words: “What is faith? How does it arise? Faith is all that is regarded as the one true.” (“Will,” No. 15, 1887)”
[Personal observation.From the chapter “The Formation of the Theory of recurrence” in the second lecture “The Eternal Regression of the Same” in Heidegger’s Nietzsche–“
(Begin excerpt)
Oh, how can I not be inflamed with the desire for eternity, for a ring within a ring, the ring of matrimony, the ring of eternal return? (Zarathustra, Part III, “The Seventh Seal”)
One of the earliest drafts written (by Nietzsche) of the eternal return narrative states,
“…. The desire to experience everything again and again and again forever.”
(End excerpt)
Eternal return is the idea of immortality. It is an idea of immortality.
Heidegger mentions Nietzsche’s strong desire for “eternity” in his chapter “The Formation of the recurrence Theory. In “Zarathustra,” the phrase “the desire for eternity” appears. Nietzsche had a strong desire for “eternal life.
Perhaps Nietzsche found it unbearable to think of “life” as something that ends only once and for all, and that after that it will be nothing forever.
For Nietzsche, who denied and rejected “life” in the afterlife and reincarnation (linear time), the only way left to “eternalize” life was to “regard” time as a circle.
If he regarded time as a circle, his “life” would be eternalized, and his “desire for eternity” would be satisfied.
Nietzsche may have thought that to regard life in the afterlife or reincarnation as one’s own thought would be to escape from one’s present “life,” to treat one’s present “life” with such disrespect, to lower the value of one’s present “life,” and to weaken one’s “will to power” to such an extent.
If time is seen as a circle, “life” is eternalized, and Nietzsche’s “desire for eternity” is satisfied.
What Nietzsche needs to ask next is how to create a “life” that is worthy of eternalization, and what kind of attitude to live a life that is worthy of eternalization.
I would like to return to Heidegger’s “Nietzsche” for further discussion of how Nietzsche thought about these points before the theory of eternal regress came to Nietzsche’s mind.