Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Pointedly Moralistic
Hawthorne really likes to tell us how it is in this story. He has a message to tell us – the story is didactic and moral – so naturally the tone is going to suit these purposes. And nowhere it the author's attitude more clear than in the story's final paragraph, when we drop the narrative altogether and hear straight from the narrator (and very possibly straight from the author – see "Narrator Point of View" for the connection between Hawthorne and his narrator):
Thus ever does the gross fatality of earth exult in its invariable triumph over the immortal essence which, in this dim sphere of half development, demands the completeness of a higher state. Yet, had Aylmer reached a profounder wisdom, he need not thus have flung away the happiness which would have woven his mortal life of the selfsame texture with the celestial. The momentary circumstance was too strong for him; he failed to look beyond the shadowy scope of time, and, living once for all in eternity, to find the perfect future in the present. (91)
The narrator is so concerned with moralizing, we don't even see the real fall out to the story's climatic scene! What is Aylmer's reaction to his wife's death? What is the deal with Aminadab's earthy chuckle? Did Aylmer learn from his mistake? We don't know, because Hawthorne's point isn't to satisfy our plot-cravings, it's to teach us a lesson. (Just what is that lesson? It's subject to debate, so see "What's Up with the Ending?" for the full-blown discussion.)