What is property, and why does our species happen to have it? In this paper I explore how Homo sapiens acquires and cognizes the custom of property and why this might be relevant to understanding how property works in the 21st century. I first support the claim that property is a universal and uniquely human custom and then I argue that humans locate the meaning of property within a thing. Using philosophy of property law and actual property disputes, I also explain (a) how my theory generates a testable hypothesis, (b) how the bundle of sticks metaphor inverts how we cognize property, and (c) how social scientists can no longer think about property as an external constraint imposed upon an individual.