Abstract
In recent years, a hierarchical view of reality has become extremely influential. In order to understand the world as a whole, on this view, we need to understand the nature of the fundamental constituents of the world. We also need to understand the relations that build the world up from these fundamental constituents. Building pluralism is the view that there are at least two equally fundamental relations that together build the world. It has been widely, though tacitly, assumed in a variety of important metaphysical debates. However, my primary aim in this paper is to argue that this has been a mistake. I will show that serious problems concerning the relationship between building and fundamentality afflict pluralism and are likely fatal to it. I claim that, for better or worse, our best hope is building singularism, the view that there is a single most fundamental building relation. I conclude by examining the advantage that singularist accounts enjoy over their pluralist rivals.