Catholicism is seen at the forefront of Irish culture in the novel and thus represents an important motif. Charting the slow transformation of religious values in Irish society from 1945-2015, the religion is painted through a largely negative lens. The events of Cyril’s life come to illustrate the Catholic Church’s influence on Irish government, its influence on people’s views of one another, and the hypocrisy that exists within it.

This hypocrisy is showcased from the very first line of the novel when it is proclaimed that the priest who threw Catherine out of Goleen was also having two affairs of his own. When Catherine is cast out for being pregnant, her family does nothing to help her. The priest drags her out of the church by her hair and throws her to the street as if she is garbage; this event sets the stage for Cyril, unknowingly fated to a life of ostracism and judgment. Throughout Catherine’s life, women are also barred from working once they were married. It was determined by the Church that a woman’s children, husband, and home should be their focus, and nothing more. It was not until the 1970s that women were finally given the right to both work and marry.

The Catholic Church’s influence on Irish government was strong in the mid-20th century when laws were still in place to control people’s basic rights. Irish law dictated that being gay was illegal, giving justification to corrupt garda who stalked gay men at night in order to catch them together and arrest them. Cyril is forced to hide his sexuality for his entire childhood and young adult life, finding affection only through short, meaningless encounters with other men in hiding. It is not until he moves to Amsterdam that he is finally able to live openly.

When Cyril returns to Ireland decades later, society’s general anti-gay stance still permeates society, but the stigma is slowly abating, and in 2015 a Referendum is made to the Constitution of Ireland stating that people of any sexuality may marry—a major change for Ireland and a strong indication of a push away from religious involvement in government. When Cyril is nearing his death, he feels happy knowing that the country’s view toward both women and gay men is improving, but also laments the way his life may have been had he not had to suffer in hiding.

Humor is a central motif in The Heart’s Invisible Furies, with every page, encounter, and character being told through a tone of light sarcasm and dry wit. Cyril’s interactions with others are often marked by this humor, such as Charles’s point-blank manner of speaking. When asked if his wife, Maude, will be joining a meeting, Charles replies, “I’d be shocked if she was…. Maude died a few years ago. Cancer. She beat it when it was in the ear canal but once it spread to her throat and tongue that was it. Curtains.” (156). When Mary-Margaret talks about almost anything, she follows it with some variation of ”That wouldn’t be my standard now at all” (196). John Boyne utilizes not only dry humor, but even makes use of slapstick, such as when Cyril shows up to meet Bastiaan’s parents and falls in a pile of cow excrement. He further expands this humor by turning the chapter title into a pun: “Pulling Myself Out of the Shit” (312), a metaphor for Cyril’s slow climb out of a lonely, deceitful life.

Even in the darkest, saddest moments of Cyril’s life, there are moments of humor interlaced with the tenderness between humans: “You were never a real Avery…. But Christ on a bike, you came close. You came damned close” (485-86). Irony is wound through the story’s plotline and characters, with priests having affairs, a married couple who believes their obviously gay son is heterosexual, Cyril’s concern when Charles is sober rather than drunk, and most importantly, Cyril’s many encounters with Catherine. Because The Heart’s Invisible Furies is a chronicling of a man’s entire life, it’s bound to be decorated with humor; the puzzling and often ridiculous nature of human beings is something that Boyne makes certain to illustrate.

Alcohol is a recurring motif in The Heart’s Invisible Furies, having a strong influence over the setting, characters, and plot. When Catherine first meets Seán, they’re on their way to Dublin where Seán plans to get a job at a Guinness Brewery. The part of the city where the brewery is located is said to smell of alcohol all day and night. It is clear from the exposition that alcohol will be a prominent influence in the characters’ lives. When Seán is murdered, his father is drunk and enraged, illustrating the dangerous effects of alcohol and how it can amplify one’s hatred. Cyril and Julian begin drinking together from the time they’re 15 or so, sneaking into pubs. The first time they go out drinking, Julian is anxious to go but Cyril is unsure. He follows along, always wanting to impress Julian, and observes the men inside the pub staring into their drinks “as if within that dark liquid the meaning of life could be discovered” (135).

As he gets older, Cyril scarcely goes a week without drinking. Throughout his life, Cyril is always meeting friends, family, and dates at pubs. In most cases, it’s a positive, social event that brings people together and helps form the connections that make Cyril’s life meaningful. Perhaps the most important connection that Cyril makes at a pub is with Bastiaan; Bastiaan becomes the love of Cyril’s life. He is introduced to Cyril through Jack, who owns a pub in Amsterdam decades later. Cyril gets to know Jack, completely unaware that Jack is best friends with his mother, Catherine; this is one of the many chance encounters in Cyril’s life that demonstrates The Interconnected Web of Human Life.