McDonagh is obviously wrestling with the recurring theme of justifying existence through artistic achievement or some type of moral code, a theme that’s recurred in his own work on the stage and screen, be it The Pillow Man or In Bruges. But he’s also creating a seemingly farcical premise to grapple with the Irish character during times of extreme strife. In Banshees, this comes in the absurd ultimatum Colm delivers to Pádraic: Leave me alone or I’ll start cutting off my fingers, one by one!
As a metaphor though, it’s not too subtly removed from the fact that in the early 1920s, many Irishmen who once considered themselves to be friends were now killing each other on the mainland. The causes and grievances which triggered that war are too trenchant to fully explore here, but suffice it to say that only a handful of months after the Irish Republican Army successfully fought a War of Independence from the United Kingdom, many of the same soldiers found themselves shooting at their former comrades due to acrimony over accepting the Anglo-Irish Treaty, which among other things only would recognize Irish independence as long as the Republic of Ireland remained a free state under British dominion (in other words, the British king would still be their head of state).
At the end of the day, friends with more in common than they had apart were willing to bring violence to bear. Some might say it was cutting off your nose to spite your face. Or cutting off your thumb to torment your best mate.
So it is in The Banshees of Inisherin that despite being surrounded by the rural, majestic beauty that cinema tends to mythologize, blokes like Pádraic and Colm are completely consumed by their perceived troubles and slights. They make a hell out of their supposed heaven, because there is something sorrowful or self-destructive in their temperaments, which eventually refuse to accept any semblance of happiness, whether that’s by having a drink with your buddy or, later in the movie, by accepting sound advice to not be such a raging, miserable bastard.
The sage advice is personified by Condon’s Siobhán, the seemingly only literate woman on Inisherin, and certainly the only person with a serious intellectual curiosity. Unlike Gleeson’s Colm, she actually knows what century Mozart lived and died in, and is clear-headed enough to see that “you’re all fucking boring!” when Colm laments to her the dullness of her brother.
In the end, Siobhán does what many Irish men and women have done through the ages, including both Ford and McDonagh’s parents: She leaves. She also begs Pádraic to come with her. When the movie begins, Farrell’s relatively innocent animal-lover is a genuinely kind person who does not care about the larger existential questions that keep Colm awake. But after Colm brings Pád down to his level of misery, the brother feels obligated to refuse his sister. He’d rather nurse his resentment for Colm until it blossoms into an eternal hatred rather than even attempt happiness. In fact, he finds something resembling contentment by the final scene, agreeing that his feud with Colm is going to follow them to their graves, even as they share responsibilities of watching Colm’s dog.