Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
From Confessional to Prophetic
Equality 7-2521, our narrator, initially speaks to us in a very confessional kind of way. He's revealing secrets about himself to us, secrets which nobody else should know. They're secrets about which he has reason to feel guilty, because so much of what he says and does is forbidden by his society:
It is a sin to write this. It is a sin to think words no others think and to put them down upon a paper no others are to see. It is base and evil. It is as if we were speaking alone to no ears but our own. And we know well that there is no transgression blacker than to do or think alone. We have broken the laws. The laws say that men may not write unless the Council of Vocations bid them so. May we be forgiven. (1.1)
Story openings don't get much more confessional than that. You could almost imagine Equality 7-2521 kneeling before a priest.
Equality 7-2521's tone changes as the story progresses, however. Gradually he grows more sure of himself, and more convinced that what he's doing is right, even if he still only writes about it in secret. Once he's stolen away to freedom in the Uncharted Forest, he no longer has reason to feel guilty or secretive, and he starts to write as if he were proclaiming his joy from the hilltops. By the time we reach the last two chapters, he's writing with the force and the confidence of a full-fledged prophet, forcefully rejecting his past and reverently singing the praises of Ego:
I am done with the monster of "We," the word of serfdom, of plunder, of misery, falsehood and shame.
And now I see the face of god, and I raise this god over the earth, this god whom men have sought since men came into being, this god who will grant them joy and peace and pride. (11.19-11.20)