Irish author Adrian Duncan's fifth novel, A Thought Without Collision, delves into the human experience of grappling with the mysteries of the universe. The story begins in Ireland in 1923, following Catherine, a six-year-old girl with remarkable academic abilities, as her family's farm struggles financially. Fast forward to 1951, where Dr. Josef Alois, a middle-aged academic from Tyrol, resides in a self-built house on Scotland's east coast. He lives in solitude until Catherine reappears—now a mid-30s Oxford professor—bringing a dramatic shift to his life. The chapter ends with a somber note: Alois is more unwell than he realizes and will die in one month and eleven days. Alois's character and parts of his fictional works are inspired by the life of Ludwig Wittgenstein, a renowned philosopher known for his work in logic and language. The novel also references Wittgenstein's contemporaries, such as G.E. Moore and Maurice Merleau-Ponty, all of whom sought to understand the world through rigorous intellectual inquiry. The narrative includes diagrams and passages of algebraic logic, illustrating the complex intellectual landscapes the characters navigate. Throughout the novel, small, enigmatic places—like "pockets" in Catherine’s mind or a swallow’s nest—serve as symbols of hidden realms that lie just beyond human comprehension. As Catherine's intellectual curiosity grows, she explores diverse fields, from advanced mathematics to the consciousness of animals. She envisions secret worlds in the sky, described as "a plane of translucent and unconnected fragments above them all." The novel's structure alternates between two time periods, creating a sense of movement and urgency, especially as Alois's impending death looms. This narrative technique allows the story to weave through different philosophical traditions while navigating distinct historical settings. Despite its intellectual themes, A Thought Without Collision remains accessible and engaging. It avoids being overly complex or frustrating for readers, instead offering mysteries that reflect the enigmas of the universe. The novel continues Duncan's signature style, marked by meticulous storytelling and a patient narrative voice. Unlike previous works that leaned on psychological ambiguity, this novel provides more definitive conclusions, offering glimpses into the characters' evolving worlds. The prose is straightforward yet rich in detail, blending elements of Irish realism with a cerebral European sensibility that touches on philosophy, architecture, and themes of exile. Every small detail, like a half-inch cube of butter, invites reflection, making the reader contemplate the deeper meanings behind the everyday.