Adam Ewing is the first character we meet, and despite being absent for nine-elevenths of the book, he undergoes the most change out of all six main characters. Even though he doesn't realize it at first, he's a conflicted man right from the start. This is a guy who religiously goes to church on Sundays (pun intended), and censors out all the d—n swear words in his own journal, yet he easily calls a mulatto woman "not far removed from the jungled breed" (1.3.1). Yikes. So much for love thy neighbor.
But Ewing is a man on a journey. Professionally, he's been sent to locate the Australian beneficiary of a will executed in California. That part's done, and he's on the long ship-ride (this is the 18th century, so no JetBlue red-eye from San Fran to Sydney) back home. What he sees on this voyage takes him on a spiritual journey, too, as he realizes that all people are on this planet together, and we should be working with each other, not against each other.
The signs of Adam Ewing's brewing inner conflict are visible early on. He fears that "gold fever" is taking over in San Francisco, for one thing. And when he finds out that the ship's crew plan to desert once they reach San Francisco, he says, "[M]y sympathies are with the seamen!" (1.9.3). Okay, so he's anti-greed and pro-worker. But race is still a touchy issue.
Things change a little bit when he accidentally tumbles into a hidden island shrine. He doesn't tell anyone about it. "The prospect of Walker & his ilk felling the trees & selling the dendroglyphs to collectors offends my conscience" (1.7.9). Ewing is one of the only characters in his journals to even have a conscience, and this shows that he is empathetic toward the tribesman of the Pacific Islands, not wanting to sell them out for his own personal gain. He even puts his own life at risk to try and save the slave Autua, who stowed away on the Prophetess. Ewing says, "[M]y word was my bond, even to an Indian" (1.10.9).
However, Ewing is unable to fully articulate his change of heart until he gets to the last entry in his journal. He's unable to really sit down and think because of a parasite wracking his brain. Diagnosed by his frenemy, Dr. Goose, the gusano coco cervello (which kind of means "coconut brain parasite") parasite turns out to be a total hoax, a ploy by the crackpot doc to kill Ewing and take his money. Although Ewing's illness was brought on by Goose, what caused the symptoms in the first place? Could it have been his conscience nagging at him?
Things start clicking for Ewing in the second half of his story. Early on, he says that "cynicism can blind one to subtler virtues" (1.2.3). Ironically, it's his optimism that blinds him to Goose's treachery.
The more Ewing sees of the world, the more he becomes not quite cynical, but realistic. He sees that men, even white men, are capable of some pretty horrendous things. He witnesses how they subjugate darker tribes. He witnesses a hazing ritual aboard the ship and observes, "Cruelty has never made me smile" (11.3.6). He hears an analogy about slave-maker ants, and starts wondering if people are really like ants after all.
The low point for Ewing is when a friend of his on the ship, Rafael, kills himself after being repeatedly raped by Mr. Boerhaave and his cronies. He is wracked with guilt over this event, wondering if he allowed it to happen by not paying closer attention to the signs, by standing by and doing nothing. He believes his ignorance contributed to the boy's death.
By the end of the novel, after black Autua saves white Ewing from death at the hands of Dr. Goose, Ewing decides to devote himself to the Abolitionist cause, "because [he] owe[s] his life to a self-freed slave & because [he] must begin somewhere" (11.15.10). Even if his contributions might be just a drop in a bucket, at least they're something.
Ewing is a good counterpoint to the cop-out excuse "that's the way things were then." The 19th century isn't exactly known for civil rights, but Ewing shows us that not everyone was a sheep who just went along with and enabled the prejudiced attitudes of the times. If that were the case, things would never change. It just took time for people to find their voices.