Seen this twice now and I love it the more that I think about it. On top of all the masterful aesthetic stuff, there's just so much to pick apart here to the point where I've come up with at least five different ways I can think of to read this film on a thematic level. If anyone has any other theories or ideas I'd love to hear them because I feel like this is barely scratching the surface; there's probably a hundred different ways to analyse The Lighthouse and they're all equally valid but for now, I hope you enjoy my plentiful bounty of hot takes:

Reading #1: The obvious one. Winslow and Thomas are two deeply unhinged, lonely people who wind up stuck in a lighthouse for weeks on end with only each other as company and form an unhealthy, co-dependent relationship built on manipulation and mutual distrust. Both men play power games with each other, both are horny as hell (and possibly homosexual) and both drink to excess - and to make matters worse there seems to be some sort of supernatural force on the island that is either driving both men insane by tormenting them with their deepest desires or is merely a physical manifestation of their already existing dysfunction. Eventually, it succeeds at playing on each character’s fractured masculinity and both men succumb to their demons and destroy one another. When Winslow finally reaches the crux of supernatural activity on the island (the light that has driven both men to murder), the things he sees inside cause him to go insane and he falls to his death.

Reading #2: Winslow and Thomas are the same person and the whole film is just one man driving himself mad with guilt. Evidence – both characters are called Thomas, both are revealed to be leading double lives (Winslow with his fake name, Thomas with his supposed lies about being a sea captain) and both have recently killed a man - noticeably, the previous lighthouse keeper that Thomas killed is shown missing an eye in the film, and the seagull Winslow kills that acts as a stand-in for his guilt over the murder of a timberman (and who’s body supposedly contains the soul of a dead sailor), is also shown missing an eye. Both men are drinkers (though the younger Thomas initially denies this), both smoke (Winslow has cigarettes, Thomas has a pipe) and there is at least one scene where their smoking implements are swapped. To look at it this way, The Lighthouse is the existential story of one man’s argument with himself as he veers between intense self-pity and self-loathing, ultimately drinking himself to death over mistakes from his past as he seeks the "light" (self-acceptance). The final shot is a metaphor for his guilt (embodied by the seagulls) tormenting him in the afterlife, indicating that he has failed.

Reading #3: The film is a commentary on capitalism, utilizing the story of Prometheus as a template. Winslow is a desperate man who is looking for work to escape dire circumstances and Thomas is a (perhaps insane) lighthouse keeper who manipulates him (gets him drunk, acts emotional, lies to him about the magical properties of the light), exploits him for labour (in his logbooks he lies about Winslow being lazy and irresponsible to keep from paying him) and attempts to drive him mad. Eventually, Thomas’ power games and their unhealthy lifestyle cause Winslow to lose it, kill Thomas and attempt to take the light for himself. Like Prometheus, Winslow wants to take the “fire” from those coveting it at the top and bring it down to Earth but when he looks inside, he realizes the light has no supernatural property and that Thomas’ powerplay was just a bunch of bullshit. He goes mad and is doomed (like Prometheus) to lie on a rock and have his insides pecked out by birds for buying into Thomas’ scheme and the myth of prosperity - this reading could even be seen as criticising the intersections between masculinity and capitalism, as the desired “light” is located at the top of a very phallic-looking lighthouse and the film makes frequent comment on how both men’s fragile egos drive them to seek dominance over one another (honestly could be a whole nother take in and of itself).

Reading #4: Thomas is some sort of deity, most likely Neptune, testing Winslow to see if he can admit to his crimes and amend them (evidenced in the scene where he appears to Winslow as God and his eyes beam light onto Winslow's face; “reading his soul” essentially). This is why Thomas keeps trying to get Winslow to “spill his beans” and Winslow always obfuscates the truth, denying he ever took part in a murder. Thomas tests him by giving him alcohol, overworking him, acting standoffish and coveting the light, which is Winslow’s way into heaven. Winslow fails this test by killing the seabird (the manifestation of his guilt and reminder of what he did) thereby making the same mistake all over again, causing the winds to change and for him to be stuck on the island (purgatory) indefinitely. He continues to make mistakes, starts drinking again, and eventually “kills” Thomas. When he attempts to ascend to heaven immediately afterwards he is driven mad by what he sees there and is deemed “unworthy,” his purgatory becoming an endless hell where he is tormented by his own guilt forever.

Reading #5: The whole movie is just gay as fuck. Thomas and Winslow are engaged in a toxic, mutually dependent relationship where both secretly want to fuck one another - through their daily activities Winslow gets to pretend that Thomas is his daddy and Thomas gets to have a submissive twink boyfriend who does everything he says, but each is prevented from acting out these fantasies because of their personal issues and the social mores of the time – the lighthouse is one big penis that Thomas covets (by having naked orgasm parties at the top), and the ocean (classically a feminine symbol) represents womanhood and both men’s fear and desire of it, both in themselves and in how they are perceived. Notice how whenever Thomas tells his sexual conquest stories they are intrinsically tied to his sea-faring lifestyle, and that the sole female character - who comes from the ocean - is at first a source of pleasure to Winslow but that quickly turns to disgust when they have intercourse. Winslow seeks to gain sexual dominance over Thomas (even though what he really wants is to be submissive and fulfil his daddy kink), but his own self-loathing causes him to kill Thomas instead, climb to the head of the giant penis and be covered head-to-toe in a bunch of white stuff. At the end of the film Winslow is essentially castrated for his sins, sprawled along the bottom of a ravine near the ocean as his (weirdly vaginal) stomach wounds lie open and exposed.

Bonus Reading #6: Thomas' farts have hallucinogenic properties and both he and Winslow were just really fucking stoned the whole time. This is the one I like to go with, personally.