Inductive reasoning leads Legrand to discover an encrypted message that he sets out to painstakingly decipher. Poe's detailed analysis of the cryptogram is quintessentially romantic, encouraging rational inquiry into seemingly supernatural phenomenon. A respect for both the natural and supernatural worlds is implied by the story. Interestingly, nothing supernatural does take place in "The Gold-Bug." Legrand admits to the striking coincidences that led him to the treasure, but coincidences themselves are not supernatural events. Legrand states, "it was not done by human agency. And nevertheless it was done." The titular bug is a scarabaeus, which is a direct allusion to ancient Egypt. Like pirates, the imagery and lore of ancient Egypt has romantic, compelling connotations for readers. The reference to the scarab is coupled with the eerie image of the skull. When Jupiter finally climbs out on the "dead" limb the situation takes on an ominous tone before resolving itself peacefully. The supernatural is always hinted at but Poe makes sure to explain every phenomenon that seems occult. For example, the narrator describes "the scarabaeus, which he carried attached to the end of a bit of whipcord; twirling it to and fro, with the air of a conjurer, as he went." Legrand is not shown to be a conjurer at all, just a man obsessed with finding a hidden treasure. His seeking the treasure is also motivated by monetary need rather than being an abstract or spiritual quest.

Budding interest in the science of mind is also a key theme in Edgar Allen Poe's work. In "The Gold-Bug," Legrand is suspected to be mentally ill. In fact, the narrator is certain that his friend is going mad and urges him repeatedly to seek help. The narrator comments on Legrand's carrying the bug like a conjurer, "When I observed this last, plain evidence of my friend's aberration of mind, I could scarcely refrain from tears." Legrand later admits to teasing the narrator and deliberately...

However, Legrand also does exhibit genuine signs of mild bipolar disorder or obsessive-compulsive disorder. Towards the beginning of the story, the narrator states, "I thought it prudent not to exacerbate the growing moodiness of his temper by any comment...I dreaded lest the continued pressure of misfortune had, at length, fairly unsettled the reason of my friend." Legrand even begins to take on the appearance of someone who is mentally ill: "His countenance was pale even to ghastliness, and his deep-set eyes glared with unnatural luster." Although it would be a full fifty years before Freud, Poe does suggest awareness of mental instability as a natural rather than supernatural occurrence.
Edgar Allen Poe's 1843 short story "The Gold-Bug" addresses attitudes towards race in antebellum America. The story is rooted in the Romantic literary tradition, while remaining grounded in historical fact as well. Even the Captain Kidd legend introduces readers to the real role of pirates during the colonial era. Poe mentions the combination of French, Spanish, and English loot. Legrand's Huguenot background also begs inquiry into the minor threads of European colonization.

The intended audience for Poe's story included any American curious about history, science, and the supernatural. The story is set in the same time it was written, which encourages the reader to identify fully with the narrator. Poe deliberately blanks out the last two digits of the dates in the story, too, which allowed his nineteenth century audience to project whatever date they wanted onto the story. Readers during the middle of the nineteenth century would have been curious about the natural sciences as well as the discovery of gold. After all, the California gold rush and the Wild West loomed in American consciousness. The idea that Americans had access to buried treasure and could get rich quick was as real in the 1850s as it is today.