In Disbelief: The Origins of Atheism in a Religious Species, Will Gervais explores the interconnected nature of religious belief and atheism in human psychology. Gervais proposes that understanding religion requires solving two evolutionary puzzles: the Puzzle of Faith, examining how Homo sapiens became uniquely religious, and the Puzzle of Atheism, investigating how disbelief exists within this religious species. This approach yields a comprehensive theory explaining both faith and atheism, shedding light on humanity's religious evolution and the current trend of abandoning belief. Gervais draws on cognitive science, cultural evolution, and evolutionary psychology to challenge existing theories of religion.

Will Gervais, PhD, is a prominent cultural evolutionary psychologist specializing in the scientific study of atheism. His research, featured in major media outlets, bridges cultural evolution, evolutionary psychology, and cognitive science. Gervais's interdisciplinary work has earned him recognition as a Rising Star by the Association for Psychological Science and garnered awards from the American Psychological Association and the Foundation for Personality and Social Psychology. In Disbelief, Gervais employs accessible prose and compelling examples to explain humanity's religious origins, the shift away from faith, and strategies for navigating religious divides in our culturally evolved landscape.

Shermer and Gervais explore the nature of religion, various belief systems, and atheism's prevalence and perception. They delve into the cognitive foundations of faith, evolutionary perspectives on religion, and its historical and societal roles. The discussion covers the adaptive nature of belief, religious diversity, and the impact of religion on personal and social well-being. They also consider the future of belief systems and potential alternatives to traditional religion.