The Odd Couple

Chapter 5 examines the relationship between religion and science, which Harari argues has been misunderstood by partisans on both sides. The popular framing treats them as opposing forces — science the engine of progress, religion the residue of superstition. Harari rejects this. He argues that religion and science have been a productive odd couple for centuries because they answer different questions. Science answers questions of fact: how does the body work, what is the structure of matter, how did humans evolve. Religion answers questions of meaning and ethics: what is right action, what makes life worth living, why does anything matter. Neither can do the other's job.

Without science, religion makes empirical claims that get falsified — heliocentrism vs. geocentrism, evolution vs. literal creation, vaccine efficacy vs. faith healing. The history of religious institutions adjusting their factual claims as science advances is, on Harari's reading, mostly a story of religion sensibly retreating from territory where it was overmatched. The Catholic Church accepted heliocentrism (eventually), accepted evolution (in 1996 under John Paul II), accepted Big Bang cosmology. These were not capitulations; they were religion specializing in its strengths.

Without religion, on the other hand, science cannot motivate action. A scientific paper can tell you that vaccines save lives; it cannot tell you that saving lives is good. Science can describe the consequences of climate change; it cannot establish that those consequences are bad and ought to be averted. Every action a society takes rests on a value claim that science cannot generate. Modern humanism — which holds that human experience is the source of all value — is, in Harari's framing, not the absence of religion but a new religion, one whose central deity is the individual human soul.

The chapter ends by setting up the central tension that drives the second half of the book. The modern social contract — what Harari calls the modern covenant — was a bargain between religion and science: religion gave up its empirical claims in exchange for retaining its monopoly on meaning. Science delivered material progress; humanism delivered meaning. The bargain has worked for about two centuries. But now science is encroaching on humanism's territory. Neuroscience is undermining the idea of a unified self. AI is undermining the idea that humans have unique intelligence. Biotech is undermining the idea that humans have a fixed nature. When science can answer the questions humanism reserved for itself, the odd couple may stop being couples. Harari thinks this transition is already happening, and that most people have not yet noticed.