I don't know if you're researching English papers or what, but here's what it means.
Nozick described his state of nature theory thus:
State-of-nature explanations of the political realm are fundamental . . . even if incorrect. We learn much by seeing how the state could have arisen, even if it didn't arise that way. If it didn't arise that way, we also would learn much by determining why it didn't; by trying to explain why the particular bit of the real world that diverges from the state-of-nature model is as it is.
If a state arises differently than the state of nature tale, our current state is "process-deficient."
EVEN the bravest that are slain
Shall not dissemble their surprise
On waking to find valor reign,
Even as on earth, in paradise;
And where they sought without the sword
Wide fields of asphodel fore’er,
To find that the utmost reward
Of daring should be still to dare.
Well, Frost's poem about angels returning to earth, is, in the same fashion, a fundamental explanation of life. It may not be true, and it may not have really happened, but it could have. The trial by existence is a process-deficient explanation of life. Things may not have happened that way--in all likelihood we did not choose the life we currently live while in heaven, and God did not lovingly send us here--but, if it had happened that way, it would have made sense. And that Frost provided an explanation for the universe that makes sense is important in itself.
Why does it make sense?
I wondered what Heaven was like. When very young, it was a childish place, with clouds and winged folk wandering about. Over time I took the idea of Heaven as perfection more seriously. Heaven would have to be a very individual thing, full of experiences tailored to the particular soul.
The angel hosts with freshness go,
And seek with laughter what to brave;—
And binding all is the hushed snow
Of the far-distant breaking wave.
My view of Heaven grew more amorphous as it grew more personal. For me, friends were there--adventures were there. Everything good. That lasted for a time, but, thought I, wouldn't complete bliss get boring? Boredom hardly sounds like a pleasing way to spend eternity--if Heaven's all it's cracked up to be, maybe we'd need some sadness to keep things from devolving into boredom.
But if a little sadness is good, why restrict it to that? Pain is good after a fashion--obstacles are good too: they feel good to overcome. Challenges are good. Complete misery can even be desirable--it makes us more real, marks important events, makes happiness brighter in comparison. And risk--what makes life exciting is the risk of pain and defeat and death.
The tale of earth’s unhonored things
Sounds nobler there than ’neath the sun;
If Heaven's perfect, it's going to have all these things in some ratio.
Of course, by now, our view of Heaven looks a lot like Earth. Life is Heaven. And if life is Heaven, then what's left for Heaven itself? Maybe a pit stop, a place where we enjoy omnipotence--but only for a while. We will need our challenges and risks.
The only way for risks to be meaningful is to give up our omnipotence. The only way to live is to give that up.
And the more loitering are turned
To view once more the sacrifice
Of those who for some good discerned
Will gladly give up paradise.
Once we get to Heaven, in time, there's nothing to do but go back.
But if we arrived on Earth knowing that perfection was waiting for us, we'd realize the risk was illusionary. If we knew this was all a passing dream, we wouldn't care for the outcome in the deep way that mortality makes us care. To live, we'd need to be ignorant of what was to come, of the truth. Life depends on not being omnipotent, not being omniscient, not being God.
But always God speaks at the end:
’One thought in agony of strife
The bravest would have by for friend,
The memory that he chose the life;
But the pure fate to which you go
Admits no memory of choice,
Or the woe were not earthly woe
To which you give the assenting voice.’
So we come back, forever and forever, forgetting perfection, because the ignorance is, quite simply, life. So here we are, caught in a perpetual maelstrom between perfection and imperfection, made tolerable, made beautiful, by our faulty memories.
‘Tis of the essence of life here,
Though we choose greatly, still to lack
The lasting memory at all clear,
That life has for us on the wrack
Nothing but what we somehow chose;
Thus are we wholly stripped of pride
In the pain that has but one close,
Bearing it crushed and mystified.