 This entry has only sampled a small portion of work relevant to the import and promise of conceptual reflection on the epistemology of developmental biology. Much more could be said about each of the above domains, such as a more fine-grained analysis of how normal stages operate as types in developmental biology (DiTeresi 2010; Lowe 2016). Additionally, little has been said about how evidence works in developmental biological experimentation or differences between confirmatory and exploratory experimentation (Hall 2005; O’Malley 2007; Waters 2007b), nor have I treated the role of metaphors and models that characterize key practices in developmental biology (Fagan 2013; Keller 2002). The latter have been perspicuously analyzed via increased attention to the details of particular research programs. Finally, nothing has been said about the metaphysical implications of developmental phenomena (a key input for  Aristotle’s metaphysics).  Concepts of potentiality are very natural in descriptions of embryological phenomena (e.g., the pluripotency of stem cells or the potential of a germ layer to yield different kinds of tissue lineages) and some have argued that empirical advances in developmental biology support a new form of essentialism about biological natural kinds (Austin 2019). This bears on how we understand dispositions (see the entry on  dispositions)  because the triggering conditions are often complex and multiply realized (including manifestations without a trigger), as well as the fact that cells exhibit dispositions with multiple possible manifestations (cell types) in specific sequential orderings (Hüttemann and Kaiser 2018; Laplane 2016). Metaphysical issues also arise in the context of human developmental biology, such as how to understand the ontology of pregnancy (Kingma 2018; Sidzinska 2017). Thus, developmental biology displays not only a rich array of material and conceptual practices that can be analyzed to better understand the scientific reasoning exhibited in experimental life science, but also points in the direction of new ideas for metaphysics, especially when that endeavor explicitly considers the input of empirically successful sciences.