[MadcapJake]

That's not it either. Eternal return is a actually a mental model to prepare yourself for all decision making: make the choice that you would be willing to live with choosing again and again for eternity. It's about removing yourself from cultural and political expectations and struggling through the only path that is uniquely you, because any less would be to lose yourself.

Someone suggested in another comment that you wouldn't know which life this is currently. This is also missing the point. Neitzchean eternal return is more like a Hell: relieving all your mistakes over and over for all time. Destined to make the same choices while woke to their failings.

The idea was to assert a non-humility and non-christian model of morality (a morality of self-realization)

[chairmanmow]

Your last sentence is correct more or less, but I will say it can be both things at once, Nietzsche was taking a big gulp with that exercise and physics is part of it based on how he thought about it in relation to reality and his timeframe, not abstract unprovable concepts - a philosopher's job isn't to take you in one direction, so that's all that matters, although I will say Nietzsche was so close, but at the same time suffered from his own fatal flaw - dogma. Though he criticized Socrates exploitation of tragedy to convolute philosophy over the years, he seemed to see in his own self as some sort of tragic figure with people using morality as a way to shortcut. His longing for the 'ubermensch' is his own kinda distorted way of longing for a Christ like figure who knows that reason should prevail over morals - he maybe shouldn't have written off psychology and the Bible so hastily.

Where Nietzsche failed to connect the dots as a result of his logical error (righteous dogma/indulging in tragedy as a moral device with his longing for a savior figure) is that he is essentially arguing that the only sin is original sin. Before I get into how his argument fits into that, let me restate his argument in a logical manner so you can tell I understand it somewhat. Morality is a problematic logical argument because it means different things to different people depending on their intrinsic motivations (which are somehwat animalistic, unless one trains one mind to think logically, and even then still one must always learn to recognize the beast) - therefore it is subjective, and non-quantifiable and therefore useless to an intellectual argument - this creates false equivalence, this creates conflicts when people insert morality into their reasoning - it is a logical shortcut.

Back to original sin - "Eating from the tree of KNOWLEDGE OF GOOD AND EVIL" - the Bible is a liar's paradox and if you start to look at it that way it's logical masterpiece and you bet whoever wrote it understood human nature and physics big time. Nietzsche believed whenever you thought you had knowledge of something, you had probably made some logical error in pursuit of a truth you wanted to believe was fixed. He is probably right - God is not divine justice and if it were we've all probably manipulated it to our subjective whims. Jesus isn't magic. But perhaps they are useful analogs : God is Truth, and unknowable - Jesus/Nietzsche/Ubermensch represents logic coupled with mankind's initial logical fallacy (pride of knowledge/divine b.s.) thus becoming a pariah (crucified/madness/misappropriated), just believing they could say something was good or evil without providing rationale as backed by a societal construct that was made to keep some kind of order (such as saying there is no relationship between physics and philosophy and religion and space/time) - but that's neither here nor there for me to speak of, I'd rather someone else pick up the hypothesis, but I may chime in if someone goes too far off course with this.