"The Tell-Tale Heart" complicates the notion of what it means to be insane; the protagonist is clearly mad, and yet he is capable of lucidly and intelligently narrating the story. Poe's narrator protests, "How, then, am I mad? Hearken! and observe how healthily -- how calmly I can tell you the whole story." The old man's eyes are employed as a symbol for the narrator's obsession and insanity. The theme of madness can be found in much of American literature, including in Shirley Jackson's story "The Lottery" and Tennessee Williams' play "A Streetcar Named Desire."
Did the narrator truly hear the dead man's beating heart? Unlikely. What prompted his breakdown was the voice of his conscience and his feelings of guilt from the crime he had freshly committed. The theme of guilt can be found throughout American literature, including in Nathaniel Hawthorne's novel "The Scarlet Letter" and Tim O'Brien's story "The Things They Carried."
When the old man senses that someone is watching him in the darkness, he emits what the narrator describes as "the groan of mortal terror." This recognition and fear of mortality is a prominent theme in the story. Death is presented as an inevitable force that the characters fear and whose approach they can sense instinctively. It is a universal theme that can be found throughout American literature, including in "The Great Gatsby" by F. Scott Fitzgerald and in much of Emily Dickinson's poetry.
The narrator's overconfidence ultimately helps lead to his demise. "In the wild audacity of [his] perfect triumph" at skillfully pretending he has done nothing wrong, the narrator invites the police officers to sit and chat. The protagonist embodies the theme of being overly confident, emphasizing the need for humility and the dangers of the ego. The theme of overconfidence leading to downfall can also be found in Jack London's story "To Build A Fire" and in David Foster Wallace's novel "Infinite Jest."