In Samuel Taylor Coleridge's epic poem, The Rime of the Ancient Mariner, the point of the story is clear in the tradition of the early Romantics. While there are several characteristics of that form of writing, including the imagination, the supernatural, the importance of the individual, etc., the most outstanding theme is that of a return to nature, and the idealization of it.
It Coleridge's poem about the unenlightened mariner (sailor), the conflict begins when, for no good reason, the man shoots, with his bow, the albatross (a large sea bird) that had been following the ship. From that point on the ship is cursed. The wind stops and the ship is becalmed. The crew runs out of water. They face the supernatural: two specters gamble for the lives of the sailors. "Life-in-Death" wins the soul of the mariner, but the others die. The mariner strives to return to England with the help of a ghostly crew (his mates, inhabited by angels); upon arriving in his home country, the mariner has learned a new love and respect for nature. It is his fate, to visit all who need to hear his story so they will know how important the natural world is.
Edgar Allan Poe's story of The Narrative of Gordon Pym is very different. Although Poe is considered a Romantic writer, the story concentrates more on the darkness in men's souls, wherever the characters travel. Pym and Augustus are confronted with mutinous sailors, a homicidal crew on a ship that "saves them," and Pym faces murderous natives who attempt to kill all of them. The end of the story is abrupt, with no sense that the survivors ever reach home again.
eNotes.com comments on what is at the heart of the story:
The philosopher Gaston Bachelard held that [Pym's tale] derived “from the deepest psychological center of Edgar Poe.” ...Edward Davidson viewed [the story] as a philosophical narrative that shows nature to be deceptive, untrustworthy, and destructive.
This same source goes on to observe:
[The story] reveals Poe’s philosophy of the relation of the self to nature, to the world, and to the universe. It also depicts a psychic quest to discover the core of the self.
By comparison, then, it would seem that the goals of each story are inherently different, and therefore the messages revealed at the end of the story are very different.
In terms of what the stories have in common, both confront nature in its glory and fury. Both protagonists are on a journey to better understand "self," though they may not be consciously aware of it.
However, where The Rime of the Ancient Mariner provides not only closure, but a moral (to respect and honor nature or risk one's very existence), The Narrative of Gordon Pym provides no closure. There seems to be no moral as the story stops abruptly. However, eNotes.com' Masterplots provide the paradoxical intent of Pym's tale:
The plot is based on a quest to find the axis of reality on which the world turns. Everything is uncertain and an illusion; to find oneself is to lose one’s self and to slip away into nothingness.
"To find oneself is to lose one's self" is the paradox. This makes more sense when we look at Poe and the kind of work he is known for: he looks into the psyche to try to find understanding, and it is often a dark discovery.
So while both stories describe an enlightening journey, the mariner returns to share his tale, while Pym is seemingly lost.