In the first page of Twenty Thousand Leagues Under the Sea, Verne personifies the human mind:
And that it did exist was undeniable. There was no longer any disposition to class it in the list of fabulous creatures. The human mind is ever hungry to believe in new and marvelous phenomena, and so it is easy for us to understand the vast excitement produced throughout the whole world by this supernatural apparition.
The personification "the human mind is ever hungry to believe in new and marvelous phenomena" adds an intensity that a more direct phrase like “people want to believe in new and marvelous phenomena” does not. The hunger is palpable—readers can feel it—and it makes them even more curious about this unnamed creature.
Calling the human mind “hungry” for new and intriguing phenomena also captures something important about the historical moment Verne was writing the novel in—global exploration and technological advancement were in the news every day and people started hearing more seemingly fantastical stories about other countries or new technologies. It’s likely that contemporary readers would understand this type of hunger, that it may even be the force behind them picking up this very book. In other words, it’s possible that Verne is also winking at the reader here, reflecting back to them their own desire to believe in extraordinary events via reading science fiction.
Verne has Aronnax use personification to describe his experience after he, Conseil, and Ned are captured and imprisoned in the Nautilus near the start of the novel:
The prison was still a prison—the prisoners, prisoners. However, the steward, during our sleep, had cleared the table. I breathed with difficulty. The heavy air seemed to oppress my lungs. Although the cell was large, we had evidently consumed a great part of the oxygen that it contained.
Describing the air as “oppress[ing]” his lungs, Aronnax communicates both the actual reality of the lack of oxygen in the submarine as well as the fact that he and the others are being held captive. In other words, this figurative language foreshadows the oppressive nature of Captain Nemo that they will soon get to learn firsthand.
It is also notable that Aronnax uses the word “oppress” here since it’s a word that Captain Nemo will go on to use as well, with himself in the victim position (declaring that a mysterious imperial ship is the “oppressor” and he is the “oppressed”). Verne intentionally challenges simple dichotomies like victim and perpetrator in his novel, encouraging readers to decide for themselves who is really oppressing whom.
As Aronnax and Captain Nemo come to know each other better after time together on the Nautilus, Nemo shares more of his love for the ocean, personifying it in the process:
“Professor, is not this ocean gifted with real life? It has its tempers and its gentle moods. Yesterday it slept as we did, and now it has woke after a quiet night. Look!” he continued, “it wakes under the caresses of the sun. It is going to renew its diurnal existence. It is an interesting study to watch the play of its organisation. It has a pulse, arteries, spasms.”
The language Nemo uses is powerful—he sees the ocean as having “tempers and […] gentle moods,” as “wak[ing] under the caresses of the sun," and containing “a pulse, arteries, spasms.” Nemo—who has lost his real family via the violence of colonization—turns the ocean into a person here, suggesting that it has become almost like a replacement family member for him. This moment humanizes Nemo, showing that in addition to being a technological genius and violent crusader, he is also simply a man who loves and appreciates the sea. This becomes one of many conversations that leaves Aronnax feeling closer to Nemo, despite the fact that the Captain is holding him as a prisoner on the submarine.