When We Cease to Understand the World is a work of historical fiction by Chilean writer Benjamín Labatut. Written as a series of five interlinked essay-style chapters, the book analyzes the toll scientific progress takes on the world and on scientists themselves. It describes the experiences of the scientists whose discoveries contributed to the development of the destructive weapons of modernity, such as mustard gas and the atom bomb. Benjamín Labatut writes in Spanish and won multiple awards for his first collection of short stories, La Antártica Empieza Aquí (Antarctica Starts Here). His first novel, Después de la Luz (After the Light), deals with similar themes of scientific discovery, genius, and “madness” in an unconventional narrative structure.

When We Cease to Understand the World is the winner of the English PEN Award and was shortlisted for the 2021 International Booker Prize.

When We Cease to Understand the World was first published in Spanish in 2019 by Anagrama under the title Un Verdor Terrible. This study guide uses the Adrian Nathan West English paperback translation published in 2021 by Pushkin Press.

Content Warning: This guide describes and discusses the source text’s treatment of death by suicide, mental health conditions, antisemitic violence, pedophilia, and sexual assault. The text also employs an established trope that connects the concepts of genius and mental illness. This tradition relies on poetic (i.e., unscientific) models of the mind that engage with concepts of “madness” that are stigmatizing.

Plot Summary

Chapter 1 of When We Cease to Understand the World, entitled “Prussian Blue,” is a primarily nonfiction essay that describes how various modern scientific innovations led to death and destruction during World War I and World War II. The chapter begins with a focus on how the first modern artificial pigment, Prussian Blue, led to the development of the poison cyanide and later the gas Zyklon B, which was used in the gas chambers of Nazi concentration camps. Cyanide was first isolated from Prussian Blue in 1782 by scientist Carl Wilhelm Scheele. In the 20th century, German chemist Fritz Haber used cyanide to develop Zyklon, which was ultimately used to kill many members of his family during the Holocaust. Fritz Haber also developed the chlorine gas that was used in World War I to kill hundreds of soldiers on the Western Front. Upon learning of this, Haber’s wife took her own life. After his wife’s death, Haber became even more devoted to scientific discovery in order to avoid thinking about her. Haber also developed a method to take nitrogen out of the atmosphere, leading to the development of artificial fertilizers that would be used to grow crops to feed the world. Labatut closes the essay with a fictionalized letter from Haber to his wife, in which Haber worries that, as a result of the newly nitrogen-rich environment, plants will one day take over the world.

Chapter 2, “Schwarzschild’s Singularity,” describes the life and work of German astronomer Karl Schwarzschild. Schwarzschild is an eccentric, hyper-focused scientist who develops an obsession with space. He discovers that a giant dying star will collapse in on itself, causing its density to be so great that the space around it will bend and cut it off from the rest of the universe. This phenomenon is known as the Schwarzschild singularity. Schwarzschild comes to his understanding while serving in the German military during WWI and communicates it to the theoretical physicist Albert Einstein. Possibly as a result of the poison-gas attack that he experiences while on the front, he develops a disease called pemphigus that causes painful ulcers and ultimately leads to his death. Toward the end of his life, Schwarzschild becomes terrified of the implications of his singularity.

Chapter 3, “The Heart of the Heart,” describes the life and work of the Japanese mathematician Shinichi Mochizuki and French mathematician Alexander Grothendieck. In 2012, Mochizuki claims to have found a solution to an advanced math problem, a + b = c. However, no one can understand his work and he refuses to explain it. Mochizuki is brilliant but painfully shy and soft-spoken. Eventually, he agrees to give a lecture explaining his proof in Montpellier, but he fails to appear, and eventually, he removes the proof from his blog and threatens legal action against anyone who shares his work. His colleagues believe he is suffering from “Grothendieck’s curse.”

Alexander Grothendieck, whose work inspired Mochizuki, is a brilliant mathematician in the 1960s in France. However, he becomes concerned about the potential applications of his work and leaves the academy in 1970 to start a commune based on the principles of pacifism, environmental stewardship, and self-sufficiency. A few years later, the commune is broken up and Grothendieck becomes increasingly isolated and idiosyncratically religious. He eventually cuts off contact with society altogether to live alone in a small village in France. Toward the end of his life, he is found by an American mathematician, Leila Schneps, but he refuses to share his work with her. He is eventually hospitalized and dies of unknown causes. While in the hospital, Mochizuki visits him and then goes to Montpellier to attempt to burn Grothendieck’s papers in the university archives. He is caught and ejected from the campus, which is why he did not give the lecture to defend his proof.

Chapter 4, “When We Cease to Understand the World,” is a story told in a Preface, five parts, and an Epilogue. It covers the development of the field of quantum mechanics, the study of subatomic particles. The Preface describes a confrontation between the Austrian physicist Erwin Schrödinger and German physicist Werner Karl Heisenberg at a conference in Munich in 1926. Part 1, “Night in Heligoland,” covers Heisenberg’s discovery of how to measure and predict quantum particles on a German island called Heligoland. Part 2, “The Prince’s Waves,” describes the life and work of the French theoretical physicist Prince Louis-Victor Pierre Raymond, 7th duc de Broglie. De Broglie finds that all matter, not just light, exists simultaneously as a particle and a wave. Part 3, “Pearls in His Ears,” is about Schrödinger’s discovery that quantum physics can be described using a wave function. Part 4, “The Kingdom of Uncertainty,” covers the conflict between Schrödinger’s findings and Heisenberg’s. It ends with Heisenberg having a hallucination that leads to the realization of the Heisenberg uncertainty principle, which holds that it is not possible to measure both the velocity and location of a subatomic particle. Part 5, “God and Dice,” describes the events of the Fifth Solvay Conference in 1927, where Heisenberg, Niels Bohr, Schrödinger, de Broglie, and Albert Einstein debate their findings, with Heisenberg and Bohr winning the argument to create the Copenhagen Interpretation of quantum mechanics. Einstein rejects this view that the foundations of the universe are fundamentally random because “God does not play dice with the universe!” (168). The Epilogue describes what happens to de Broglie, Einstein, Schrödinger, and Heisenberg after the conference.

Chapter 5, “The Night Gardener,” is a first-person, present-day narrative told by an unknown narrator in six parts. The first part is a dream-like premonition of the horrors that scientific progress will inflict on the world. Part 2 describes the narrator meeting a man who is gardening at night, the night gardener, who tells him about a rotting tree outside his house that his grandmother hanged herself from. In Part 3, the narrator goes on a walk in the woods with his daughter, where they come upon two dead dogs who have been poisoned. In Part 4, the narrator describes how his garden grows slowly and the night gardener tells him how fertilizer was made by Fritz Haber, inventor of chlorine gas. In Part 5, the narrator discusses the old-growth woods near his town. He also describes how he bought his house from a retired lieutenant who served under the right-wing Chilean dictator Pinochet. In the sixth part, the narrator reveals that the night gardener used to be a mathematician who became a recluse after learning about Grothendieck. The night gardener tells the narrator about how lemon trees give forth a final burst of fruit before dying; he compares this to the human condition.