In this talk, I will first introduce the proposal that human reasoning relies on an inherence heuristic, an implicit cognitive process that leads people to explain the patterns observed in the world in terms of the inherent features of their constituents. I will then provide evidence for this proposal, evidence that suggests the inherence heuristic is an automatic process that exerts a ubiquitous influence on how we make sense of the world. Its influence is detectable even in the first few years of life, as indicated by the developmental studies I will present. In the second part of the talk, I will argue that the inherence heuristic may be at the root of several other phenomena of great interest to cognitive and social scientists. In particular, I will highlight, and provide evidence for, the links between the inherence heuristic and (1) psychological essentialism (the common belief that natural and social categories are underlain by hidden, causally powerful “essences”) and (2) system justification (the tendency to believe that one’s sociopolitical system is fair, natural, and legitimate). In sum, this talk will illuminate a cognitive process that emerges early in life and has profound effects on many aspects of human psychology.