Could perseverance be an appropiate theme for "The Pit and the Pendulum?"
While reading the story I felt that the narrator's consistent effort to defy his captors, most notably towards the end, established a theme of perseverance.
Am I on the right track? I am aware of the other themes of the story, I just wanted to maybe step outside the box.
I think this is a very interesting theme to explore. However, the best arguments are ones that look at both sides, especially arguments against what you are trying to show. Therefore, you will want to think through the following aspects of the story. I agree that perseverance is shown in particular with the incident with the pendulum, however how can we argue that the narrator shows perseverance when he is exploring the cell he is in and literally stumbles across the pit? There appears to be more luck in this incident of survival than anything else. You could likewise argue that he survives the pendulum only because of a blind response to a terrifying fear.
However, the oppositie of this would be the calculated way in which the protagonist seems determined to survive. He explores his cell scientifically, and then carefully constructs a plan to free himself from the pendulum:
Nor had I erred in my calculations--nor had I endured in vain. I at length felt that I was free.
Such quotes, referring to the "calculations" of the protagonist, suggest that perseverance is indeed a very evident theme of this great short story.