The episode "Outlaws", although a fine character piece, initially appears unconnected to the larger narrative of the show, especially as it is a season one episode from before the series' dense and sprawling Myth Arc properly took off. However, on a thematic level, this one tells the story of the whole six-year narrative in microcosm, revealing what the series was doing and—more importantly—what it was not doing, a whole five years ahead of finale.
On the Island, Sawyer is haunted by the memory of his father's murder-suicide and how it drove him to murder a largely innocent man named Frank Duckett. When a boar starts harassing him, and him alone, he becomes obsessed with the idea that the boar is a reincarnated Duckett out for his blood. This leads to a Moby-Dick-style trek into the jungle. Kate tags along as the voice of reason, offering him simpler and more logical explanations such as the boar having picked up his scent. But Sawyer ignores her appeals to rationality and plunges deeper into the jungle in search of his elusive animal foe. The connective thread being drawn is that, obviously, he wants the boar to be a reincarnation of Frank Duckett and is ignoring any evidence to the contrary. He wants this to be true so that he can work out the issues that have left him scarred and broken. Indeed, when he finally confronts the boar and is about to kill it, he instead decides to leave it alive with the quip that, "It's just a boar." But he does let it go (Arc Words for the series). In Sawyer's eyes, it seems as if a burden has been lifted; an old act of violence has been symbolically repeated with a more peaceful outcome.
Crucially, the episode never reveals whether the boar was actually supernatural. It could have been a divine sign sent by the Island, or it could have been a normal boar acting on any of the eminently rational reasons Kate listed. The "answer" wasn't the point—the point was that Sawyer was projecting his own inner, subconscious issues onto something in the outside world, and that influenced his behavior and actions. One season later, when this situation is reiterated with a croaking frog triggering Sawyer's feelings of guilt and remorse, Sawyer instead kills the animal that is causing him grief because he's consciously trying to renege on his character development and become a cold-blooded hardass again.
This theme, that the world is an ambiguous place where people project their subconscious issues onto events that may not have any meaning whatsoever, is one that recurs right up until the finale.
John Locke spent the majority of the series desperately trying to believe that a higher power is guiding events, while Jack Shepherd tried his hardest to deny it. Not because of a lack of evidence for or against, but because their psychologies depend on what they believe. They selectively deny anything that contradicts their belief system out of sheer stubbornness (cf. "Orientation"). Jack has a compulsive need to fix things through his own free will, and Locke has a compulsive need to surrender to his destiny. The omens and mysterious happenings that the show trucks in are really just fodder for this battle of wills. Is a deity's hand at work in events, or not? It's nothing more than a rephrased riff on whether Sawyer's boar is the reincarnation of Frank Duckett.
Although we do eventually find out the answer (it's "Yes"), ultimately the two deities driving the narrative are treated like symbolic father figures to the main characters. Their manipulation reflects the same tactics and techniques the characters' own fathers use that created their emotional issues in the first place, leaving it ambiguous how "good" or "evil" Jacob and his brother ultimately were. They are just as much a product of their own parent. The concept of destiny and free will shaping the world of the show is just an expression of their own personal psychological idiosyncrasies. In other words, they look outwards and see inwards, just as Sawyer did with the boar.
Uniquely, Sawyer is the product of three fathers—his own, Locke's, and Jack's, as it was Jack's father who inadvertently goaded him into killing Duckett. Christian gave Sawyer innocent advice which Sawyer interpreted differently according to his own views and issues, leading him to murder Duckett; it is "Outlaws" that shows him finally beginning to turn back towards the light. The closest thing to a "moral" the show had is that everybody takes their carry-on baggage with them on this wild flight of life, and "Outlaws" is the most potent example of how to unpack it and become a better person by sorting it out. A theme that resonated through the show to the very end. This episode succinctly accomplishes in forty-five minutes what—on a macrocosmic level—it took the show six years to do. After all, the last scene is of Jack and Locke leaving their father-induced ideological differences behind and embracing each other. Instead of squabbling over the signs and portents offered up by the narrative, they're content to forgive themselves and, more importantly, live and let live.
Just like Sawyer and his boar.
The show repeatedly hammers home the idea that peoples' belief systems are created by their relationship to their parents.
Jack is compelled to fix things through sheer force of personal agency because his father told him he doesn't "have what it takes". Locke desperately needs to believe he has a destiny because he craves a cosmic father figure after his own scammed him out of a kidney. Both fathers are conmen, even if Christian Shepherd had the ostensibly noble motive of giving his son the drive to succeed. Like the historical John Locke wrote, people are all born as blank slates, with our parents as the authors of our personalities.
As the show wears on it becomes apparent that two godlike figures, Jacob and his brother, are playing a cosmic game, with the castaways as pawns. Through unfathomable rules these beings appear and, like conmen, psychologically manipulate the pieces to get them to act according to some ineffable stratagem. The remote and aloof Jacob pushes people into Jack's path while staying removed and letting Jack figure things out for himself, which is all Jack wanted in a father; the Man in Black, meanwhile, is constantly encouraging Locke to embrace his destiny as a savior and as a messiah, which is all Locke wanted in a father. These cons/games may seem cruel and callous, and yet the Island's mysterious golden heart appears to be safe and everybody appears to have worked out their psychological issues. So, are Jacob and the Man in Black ultimately good, evil, or merely mortal men with godlike powers playing out a petty sibling rivalry?
The answer is that there is no answer. There are as many individual rubrics and value systems for deciding 'meaning' as there are human beings. The only constant is this world we share, and the actions we undertake.
It is a person's emotional baggage that shapes their view of that world. An ambiguous situation may be accepted as proof or rejected as a lies according to whatever filtering system is bubbling under a person's conscious mind. The central theme of the show is dealing that baggage, because it makes a person vulnerable and easily deluded by charlatans, shamans, and con men. Something the historical John Locke also had quite a bit to say about.
The show's ambiguity is meant for the audience just as much as it is the characters. Recall the final scene, where Jack reconciles with his father under a stained glass window with different religious symbols all radiating out from a central, archetypal light. Just like The Hero with a Thousand Faces speaks of the world-soul and the navel of the universe in vague terms to encompass all the different cultural variations on the archetype, the show dresses up its archetypal story of conflict between fathers and sons, heroes and gods, and free will versus destiny with allusions to mythology, religion, and popular fiction.
By not limiting the story to a set "answer", it frees the story to become anything and everything a viewer can see in it, like a Rohrschach test or even This Very Wiki.