Themes are the fundamental and often universal ideas explored in a literary work.

Art As a Vehicle for Truth

As Loxias and Bradley Pearson explain in their forewords and postscripts, art is one of the rare venues that allows for the articulation of truth. As Loxias says in the conclusion of the novel, "art tells the only truth that ultimately matters." As a follower of the ideas of Plato, Iris Murdoch believes that the world of everyday life is a world of illusions, behind which exists a world of truth, containing "ideal forms". When one is finally able to see the world of ideal forms, one is glimpsing truth. In a realm with both illusory and "true" worlds, art holds a special place, because through it an artist is able to bring viewers out of the illusory plane and into the true one. Art serves as a fundamental philosophical tool that can alert the world to higher meanings in life. Bradley Pearson's struggle to write a deeply meaningful novel in The Black Prince captures one artist's attempt to preserve a glimmer of truth for others. Although Pearson is struck by writer's block for most of the novel, his experience of Eros allows him to create the ultimate master work. In doing so, as P.Loxias (the God Apollo) suggests, he is able to bring truth to us, the readers.

Eros's Facilitation of Expression

Bradley Pearson's experience of Eros gives him the ability to write. "Eros" refers both to erotic love and to a deeper lust for power, love, and desire. Bradley's experience of Eros originally starts as pure love for Julian Baffin: he becomes happy and pleasant after feeling it. As his love turns towards lust, however, he begins to refer to his Eros as "black Eros," referencing the negative qualities that overtake him during his obsession with Julian. Despite the potentially destructive power of Eros that Bradley experiences, it still is the avenue that allows him to glimpse truth. After such a sudden and intense voyage with Eros, Bradley emerges changed and is finally able to express truth through the creation of art.

The Randomness of Life

Iris Murdoch was not an existentialist, but she shares the existentialist idea that life has no greater purpose than what individual humans designate. For Murdoch and existentialists, there is no God who has preordained one's life path before one is born. Instead, one is born with freedom to create whatever type of life that one chooses. Despite the ability to be free, most people generally prefer to cling to a preordained meaning by believing in God, or by assigning meaning to everything that happens to them. In an effort to counter this tendency, Murdoch attempts to argue for the random nature of life in her novel. For example, Bradley and Julian randomly meet twice, but there is no sense that their coincidental meetings were meant to be. Likewise, a series of random arrivals and meetings drive the entire plot of her novel. These events are what make up people's lives, but they were not each individually plotted by the Fates. As Murdoch demonstrates, life is just a series of random accidents connected together.