Is the murderer in "The Tell-Tale Heart" sane or insane?
There are several significant pieces of information that suggest that the narrator of "The Tell-Tale Heart" is insane. The narrator begins by attempting to convince his audience that he is not mad before mentioning that he hears all things in heaven, earth, and hell. Typically, a sane, reliable person would not need to persuade the reader that they are not mad. A sane person would also not believe they could hear things in heaven and hell. The narrator then mentions that he loves the old man while he plots his murder. The narrator's conflicting emotions and actions indicate that he is clearly mentally unstable. The fact that the narrator says the only reason he wants to murder the old man is because of his Evil Eye is additional evidence to support the claim that he is insane.
The narrator then attempts to persuade the audience of his sanity by describing the precautions he took to hide the old man's body. He proceeds to tell the reader that he chopped the old man's body up and hid the parts underneath the floorboard. This graphic display further illustrates his insanity. Finally, the narrator begins to experience auditory hallucinations as the police officers question him. He ends up admitting his guilt and showing the officers where he hid the old man's body at the end of the story. Overall, the narrator's attempts to convince his audience that he is sane, his contradicting statements, his horrific crime, and auditory hallucinations support the claim that he is insane.
The murderer keeps insisting that he is sane. In fact, he seems to be telling, or writing, this story specifically in order to prove his sanity. In doing this, however, he gives more and more evidence that he is insane. Evidently he has been arrested and is being held in custody. He has apparently been examined and declared to be insane. He says, "...but why will you say that I am mad?" and "You fancy me mad." It would seem that his best course under the circumstances would be to let his keepers think he is mad. Otherwise he would be tried and found guilty of premeditated murder and executed. The fact that he is trying to prove he is sane seems to offer proof to the contrary, because he would only be hurting himself by succeeding in proving he is not mad. The strongest proof that he is insane is in his hearing the victim's heart beating after he has not only killed him but "...cut off the head and the arms and the legs." Poe seems to have described this dismemberment in order to make the reader feel perfectly certain that the heart could not possibly be really beating. The murderer/narrator had been mad all along but had succeeded in concealing it from everybody until the officers came and he began imagining he was hearing that heart beating louder and louder. It might have been his own heart he could hear beating. He begins his story by saying that he is "...very, very dreadfully nervous."
From the very beginning of the story, the narrator is adamant that he is sane. In fact, he says he is not mad, just very nervous because of a situation he found himself in:
TRUE!—nervous—very, very dreadfully nervous I had been and am; but why will you say that I am mad?
The narrator is so keen to prove his sanity that he recounts how he came to murder the old man with whom he lived. Some of the details of his story, however, suggest the narrator suffers from some kind of mental instability. He claims, for example, that the old man had an evil eye—the "eye of a vulture"—which caused him great distress and really "vexed" him.
Despite the narrator's claims that a "madman" could not plan such an intricate murder, the ending of the story provides further evidence that he is, in fact, insane. Specifically, the narrator suffers auditory hallucinations in which he hears the "beating heart" of his victim. The narrator is so haunted by the sound that he rips up the floorboards and reveals his crime to the world. These actions suggest the narrator is far more insane than sane.