Throughout “The Tell-Tale Heart,” the narrator constantly has contradictory, delusionary thoughts that provide strong insight into his mental instability. The first line of the story establishes this madness: “True! —Nervous—very, very dreadfully nervous I had been and am! But why will you say that I am mad?” (Poe 3) Within this line, the narrator sets up a blatant contradiction: he admits to suffering from acute anxiety, but he also insists that he is not “mad,” or insane. The narrator reinforces this madness when he begins to describe his obsession with killing his neighbor, an old man who had not harmed him in any way: “It is impossible to say how the idea first entered my brain; but once conceived, it haunted me day and night” (Poe 3). In other words, the narrator has no idea why he has a strong desire to kill the old man, aside from the old man’s “pale blue eye, with a film over it” (Poe 3). However, even though he has no real reason for wanting to kill the old man, he continues to plan this murder obsessively, which demonstrates how twisted his mind has become.
Not only do the narrator’s thoughts reveal his madness, but also his actions. He treats the old man completely differently in different situations; when the old man is awake, the narrator greets him courteously, but when the old man sleeps, the narrator spies on him: “And every morning, when the day broke, I went boldly into the chamber, and spoke courageously to him, calling him by name in a very hearty tone, and inquiring how he had passed the night. So you see he would have been a very profound old man, indeed, to suspect that every night, just at twelve, I looked in upon him while he slept” (Poe 4). The narrator demonstrates two different types of behavior, interchanging between both easily, and this provides further evidence of the narrator’s madness. In the full expression of his insanity, the narrator also murders the old man, and after murdering the old man, he fears capture. He then embarks on the grotesque act of dismemberment: “First of all I dismembered the corpse. I cut off the head and the arms and the legs. I then took up three planks from the flooring of the chamber, and deposited all between the scantlings” (Poe 6). The narrator performs this action out of the fear of discovery, and he reveals his insanity further when he asserts, “no human eye—not even his—could have detected anything wrong” (Poe 6). Though the old man is now dead, the narrator refers to him as if he were still alive.
Lastly, Poe uses the narrator’s hallucinations to illuminate the depth of his insanity. The narrator has a delusional sense of his own powers, which is made clear in the following line: “A watch’s minute hand moves more quickly than did mine. Never before that night had I felt the extent of my own powers—of my sagacity. I could scarcely contain my feelings of triumph” (Poe 4). Having an exaggerated sense of power often characterizes mentally insane individuals, from dictators to serial killers. However, the narrator also experiences auditory hallucinations, particularly the auditory hallucinations that pertain to the old man’s heartbeat: “Now, I say, there came to my ears a low, dull, quick sound, such as a watch makes when enveloped in cotton. I knew that sound well too. It was the beating of the old man’s heart. It increased my fury, as the beating of a drum stimulates the soldier into courage” (Poe 5). This hallucination plagues him throughout the story and during the old man’s murder: “But the beating grew louder, louder! I thought the heart must burst. And now a new anxiety seized me—the sound would be heard by a neighbor! The old man’s hour had come!” (Poe 6). This heartbeat eventually becomes the narrator’s undoing, as he cannot hold himself together anymore in front of the police officers: “I talked more quickly—more vehemently; but the noise steadily increased. I arose and argued about trifles, in a high key and with violent gesticulations, but the noise steadily increased … It grew louder—louder—louder!” (Poe 7). Soon after this hallucination, the narrator breaks down, lifts up the planks, and essentially confesses his crime by screaming, “Villains! … Dissemble no more! I admit the deed! —Tear up the planks! —Here, here! —it is the beating of his hideous heart!” (Poe 8).
Throughout “The Tell-Tale Heart,” Poe provides keen insight into the narrator’s mental instability through the depiction of the narrator’s thoughts, actions, and hallucinations. The narrator thinks in a manner that is both logical and insane, often contradicting himself within the same thought. Not only are his thoughts disordered, but also his actions, from spying on the old man while he sleeps to ultimately murdering him when he is asleep. Lastly, the narrator experiences repeated hallucinations, especially the hallucination of the old man’s heartbeat. This hallucination ultimately results in the narrator’s confession, which justifies the story title, “The Tell-Tale Heart.”