In: V. Petrov/A. Scarfe (eds.) 2015, Dynamic Being, Cambridge Scholars, 2‐28. 1 Aristotle’s ‘completeness test’ as heuristics for an account of dynamicity Johanna Seibt Aarhus University Abstract: If being were ‘dynamic,’ would it be more amenable to a definition? In this paper I present a number of preliminary considerations for an exploration of this question. Working from the methodological stance of analytical ontology, I assume that the first task for an ontology of dynamic being(s) must be to locate suitable linguistic data that can represent the conceptual content to be modelled by an ontological domain theory. I try to show that Aristotle’s so‐called ‘completeness test’ in Metaphysics Θ. 6, and the discussion of this passage in Aristotle scholarship, offers some useful heuristic leads to a class of inferential data (aspectual inferences) that analytical ontologists have all but overlooked so far. In addition, I suggest that the passage also can offer some ideas about how one might formulate, in mereological terms, a component of an implicit definition of dynamicity. The study of dynamic being or ‘dynamicity’ is an unlikely task for a present‐day analytical ontologist. Other modes of being, such as actuality, possibility, and necessity, have been dominating the discussion during the early decades of post‐ war analytical ontology, together with a focus on the ontological reduction of universals; even during the last three decades, when the spotlight finally turned onto the category of events, the problem of existence in time, and the ontology of emergence, the investigation of the nature of dynamic being remained outside the purview of the mainstream debate. With the exception of work on verbal aspects, it seems fair to say that analytical ontology so far has been strikingly disinterested in the exploration of dynamicity and the forms of dynamic being. How should one interpret this startling neglect? Is this another instance of the “Werdensvergessenheit” that Nietzsche castigated as the distinctive mindset of Western metaphysics? 1 And if so, is it a purely sociological phenomenon, a case of theoretical habituation that is reinforced and propagated by the review system for professional publications that gained such weight in 20 th century analytical philosophy in general? Or is it rather, as Bergson would have us explain, the inevitable outcome of using the wrong investigative 1 Cf. Nietzsche (1882/1974), 306.