Each thing is fundamental. Not only is no thing any more or less real than any other, but no thing is prior to another in any robust ontological sense. Thus, no thing can explain the very existence of another, nor account for how another is what it is. I reach this surprising conclusion by undermining two important positions in contemporary metaphysics: hylomorphism and hierarchical views employing so-called building relations, such as grounding. The paper has three main parts. First, I observe hylomorphism is alleged by its proponents to solve various philosophical problems. However, I demonstrate, in light of a compelling account of explanation, that these problems are actually demands to explain what cannot be but inexplicable. Second, I show how my argument against hylomorphism illuminates an account of the essence of a thing, thereby providing insight into what it is to exist. This indicates what a thing, in the most general sense, must be and a correlative account of the structure in reality. Third, I argue that this account of structure is incompatible not only with hylomorphism, but also with any hierarchical view of reality. Although hylomorphism and the latter views are quite different, representing distinct philosophical traditions, I maintain they share untenable accounts of structure and fundamentality and so should be rejected on the same grounds.