Surfaces have been much studied, but no consensus has been reached about the actual physical nature of the surface of a three-dimensional, mind-independent physical object. I analyze, from a common sense or “folk” perspective, the surface of a physically-extended simple in a space containing no other objects. From this, I propose the novel idea that a surface is not a part of an object or its outside but instead is made of two components: 1) the object as a unit whole, (...) or a unity, which acts as a barrier to 2) the outside space next to the object. I further propose that if there is no pre-existing outside space, the process of grouping zero or more things together into a new unit whole and physical object creates one with the grouping/unit-wholeness acting as a barrier to that newly created outside. A second test case containing 3 components and an observer is used to defend the hypothesis that a new outside space is created by the grouping process. When combined with a previously published example of an extended simple containing nothing inside, the two-part surface hypothesis suggests a process by which this simple can undergo self-replication leading to a Big Bang-like expansion of space. This offers a possible solution to an important question in philosophy: How do you start with one or a few fundamental existent entities and end up with the many contingent entities we see in the universe around us? (shrink)