Conrad’s use of foreshadowing in Heart of Darkness is peculiar because it does not function to foretell future events so much as it serves to prefigure the darkening “mood” of Marlow’s story, which grows progressively bleaker the further he and his crew travel into the jungle. The opening pages of the novella provide a strong example of this technique. Take, for instance, the ominous sky that the passengers of the Nellie observe to their west, where the River Thames flows into the North Sea. The sky is luminous and gauzy above the Nellie, but over the sea—that is, in the direction a ship would need to take to leave England for Continental Europe or Africa—there is a “brooding gloom” that “became more sombre every minute as if angered by the approach of the sun.” The play of light in the opening pages of the novella foretell the darkness to come, both literally, as the sun is about to set, and figuratively, as Marlow begins to tell his story of his journey into moral obscurity in a largely unknown part of the Congolese jungle. 

Foreshadowing in Heart of Darkness also occurs through symbolism. For example, when Marlow travels to Brussels to get his assignment, he encounters two mysterious women who are knitting black wool. Marlow finds their “swift and indifferent placidity” troubling, and he comments that they “seemed uncanny and fateful.” Here, Marlow alludes to the Greek Moirae, three sisters who in English are known as the Fates. According to Greek myth, the Fates have the gift of foresight and know each human being’s destiny. One of the Fates spins the life-thread for each human, another one measures it, and when the time comes for the individual to die, the third one cuts it. Marlow feels uneasy in the presence of these women, who he feels may portend his death. Regarding one of the women, Marlow reflects: “Not many of those she looked at ever saw her again—not half—by a long way.” He fears that he, too, may be one of these men who never return. 

Conrad also treats foreshadowing itself as a theme, as when Marlow frames his story as a tale about how history repeats itself. Marlow begins his narrative by talking about Roman imperialism in England, which is a history that foreshadows the modern form of imperialism that he examines in his story. Marlow imagines an ancient Roman commander coming to the wilds of England, where he would be surrounded by savagery and could submit to “the fascination of the abomination.” This imaginary commander clearly foreshadows Kurtz, who travels to the wilds of Africa and submits to his own fascination with abomination. The theme of foreshadowing returns again, early in Marlow’s journey along the West African coast. Standing on a hill, Marlow observes the suffering of African slave laborers. He then has a prophecy about the evil he will face later in his journey: “I foresaw that in the blinding sunshine of that land I would become acquainted with a flabby, pretending, weak-eyed devil of a rapacious and pitiless folly.” As Marlow goes on to explain, this ominous “warning” would come true, “several months later and a thousand miles farther.”