The structure of being (in Heidegger's Being and Time)
Keywords: pros hen homonymy
Dasein
ontological pluralism
Being
Sein und Zeit

“Ontological pluralism” (OP) - supported today by philosophers such as McDaniel (2009, 2017) and Turner (2010) - claims that ‘being’ (in its existential sense) picks out a number of different features of reality that do not share any common characteristics. But if OP is not a view about these common characteristics – of which, it claims, there are none – then is it a view about anything? McManus (2013a) argues that Heidegger - an outspoken historical advocate of OP - failed to address this problem, and several related challenges that arise for him from his commitment to OP. However, I argue that Heidegger in fact solves it (as well as some other challenges raised for him by McManus) in Section 4 of his Being and Time (BT), where he claims that the inquiry into Being that he proposes must take the form of an inquiry into “Dasein”: into the kind of being enjoyed by whoever can undertake such an inquiry. On my interpretation, Heidegger takes guidance from Aristotle, who argues in Metaphysics, Gamma 2 that substance is the central modality of Being, to which other modalities are related in the “pros hen” way, and, as such, also the principal object of the “science of being as being.” I argue that what distinguishes Dasein from other kinds of beings is its capacity to be affected by Being in all of its diverse modalities (all of which bear on Heidegger’s inquiry into Being that Dasein is said to be able to perform) and that, in like manner, it is the process through which different kinds of beings leave their imprint on Dasein (an instance of Aristotle’s formal causation) that holds Heidegger’s conception of Being together as the subject-matter of a single inquiry.
In Chapter 1, I offer an analysis of the challenges to Heidegger’s version of OP raised by McManus (2013a), and I answer some of them directly. In Chapter 2, I offer a reading of Heidegger’s writings bearing on pros hen homonymy (his notes for “Basic Concepts of Ancient Philosophy” and “Interpretations from Ancient Philosophy” from the Summer Semesters 1926 and 1931 as well as BT itself). I argue that, in its basic thrust, Heidegger’s understanding of the phenomenon agrees with that defended by Shields (1999) and Ward (2008). In Chapter 3, I offer a critical assessment of Shields (1999) and Ward (2008) and I defend an account of pros hen homonymy that hopes to improve on them, distinguished by its employment of the notion of the priority in the causal network (PCN): I argue that PCN explains the centrality of some instances of a pros hen homonyms with respect to other instances. In Chapter 4, I outline my ‘post-Aristotelian’ interpretation of Dasein over against the prevailing one, according to which Dasein’s “understanding of Being” somehow determines (instead of being determined by) Being. I argue that such a ‘post-Kantian’ interpretation of Dasein – I focus on Philipse (1998) and Carman (2003) – cannot give Heidegger an answer to the “problem of the unity of Being” (SZ: 3 [1]) without revoking his commitment to OP, and that for this – and several other reasons – we should move beyond it.