Evan Welchance

Call metaphysicians who think that chains of ontological dependence must terminate in a collection of fundamental entities "foundationalists". Call metaphysicians who think that chains of being can proceed ad infinitum "infinitists". Foundationalists claim that foundationalism displays certain theoretical advantages over infinitism. First, some maintain that infinitism has a special explanatory problem that foundationalism doesn’t. Second, others maintain that foundationalism exhibits greater theoretical unity than infinitism. I argue that these considerations give us no reason to prefer foundationalism to infinitism. Against the foundationalist’s first purported advantage, I argue that foundationalists must make theoretical concessions similar to those infinitists must make (§1). And against the foundationalist’s second purported advantage – an advantage infinitists haven’t yet addressed – I argue that infinitism exhibits a different, but nevertheless attractive, kind of theoretical virtue; namely, infinitists explain all existence facts in similar ways (§2). I conclude that foundationalism and infinitism are, at worst, on a theoretical par (§3).

"Ordinary ontology" is the thesis that there exist ordinary objects like rocks, but no extraordinary objects like trogs (mereological sums of tree trunks and dogs) or incars (objects essentially co-located with cars inside of garages). Metaphysicians almost uniformly reject ordinary ontology. Most do so based on the charge that ordinary ontology is objectionably parochial, placing the unique concerns of human beings over the objective ontological truth. I contend that this charge – and thereby the almost uniform rejection of ordinary ontology among metaphysicians – rests on an empirically outdated picture of perceptual experience. In this dissertation, I argue that replacing this picture with a contemporary account of perception in better empirical standing vindicates ordinary ontology. Here’s how I proceed. In Chapter 1, I argue that perception (properly construed) justifies claims about the persistence of objects. In Chapter 2, I defend ordinary ontology by arguing that perception provides us with evidence for both the existence of ordinary objects and for the nonexistence of extraordinary objects – as such, I conclude that material object ontology is an empirical discipline. Finally, in Chapters 3 and 4, I leverage my claim that material object ontology is an empirical discipline to diagnose where several challenges to ordinary ontology go awry.

I provide a new, perception-based defense of "ordinary ontology", the thesis that there exist ordinary objects but not extraordinary objects. To that end, I first outline a story about perception and perceptual justification – one informed by recent advances in cognitive science and philosophy of perception – according to which perception gives us reason to countenance ordinary things (§1). I then argue that extraordinary objects are just the sorts of entities our perceptual apparatus is well-poised to detect; thus, the fact that we fail to see extraordinary things gives us perceptual reason to repudiate them. I conclude that ordinary ontology is true (§2-4). In closing, I show that my way of defending ordinary ontology reveals that one of the most prominent objections to ordinary ontology rests on a mistake (§5).