This chapter explores the evolutionary roots of human cognition and how they gave rise to belief in supernatural forces. It identifies four key traits—causal reasoning, symbolic thought, information sharing, and routinized behavior—that made humans uniquely capable of manipulating their environments and thriving across diverse ecosystems. Yet, when confronted with phenomena they could not explain, humans extended these same cognitive tools to interpret the unknown as intentional agents. This tendency to attribute purpose and will to natural events produced early conceptions of spirits, deities, and ancestors. Drawing on psychological studies, ethnographic accounts, and primate behavior, the chapter argues that supernatural thinking emerged not as an error, but as an adaptive framework for managing uncertainty and understanding causality. Even as human knowledge expanded, this inclination persisted, shaping religious and symbolic thought as enduring expressions of our evolved mental architecture.