Thomas Oberle

There is a ubiquitous claim in the grounding literature that metaphysical foundationalism violates the principle of sufficient reason (PSR) in virtue of positing a level of ungrounded facts. I argue that foundationalists can accept the PSR if they are willing to replace funda- mentality as independence with completeness and deny that ground is a strict partial order. The upshot is that the PSR can be compatible with both metaphysical foundation- alism and metaphysical infinitism, and so presupposing this fixed explanatory demand need not beg the question in favour of either view.

Metaphysical foundationalists argue that without fundamental facts, we cannot explain why there exist any dependent facts at all. Thus, metaphysical infinitism, the view that chains of ground can descend indefinitely without ever terminating in a level of fundamental facts, allegedly exhibits a kind of explanatory failure. I examine this argument and conclude that foundationalists have failed to show that infinitism exhibits explanatory failure. I argue that explaining the existence of dependent facts in terms of further dependent facts ad infinitum is unproblematic by arguing for the plausibility of a ground-theoretic version of the Hume-Edwards Principle, which states that if each fact in a plurality of facts has a ground, then the plurality itself has a ground.

A prominent Thomistic cosmological argument maintains that an infinite regress of causes, which exhibits a certain pattern of ontological dependence among its members, would be vicious and so must terminate in a first member. Interestingly, Jonathan Schaffer offers a similar argument in the contemporary grounding literature for the view called metaphysical foundationalism. I consider the striking similarities between both arguments and conclude that both are unsuccessful for the same reason. I argue this negative result gives us indirect reason to consider metaphysical infinitism as a genuine possibility, the view that chains of ontological dependence or ground can descend indefinitely.

There has been an explosion of interest in the metaphysics of fundamentality in recent decades. The consensus view, called metaphysical foundationalism, maintains that there is something absolutely fundamental in reality upon which everything else depends. However, a number of thinkers have chal- lenged the arguments in favor of foundationalism and have proposed competing non-foundationalist ontologies. This paper provides a systematic and critical introduction to metaphysical foundationalism in the current literature and argues that its relation to ontological dependence and substance should be qualified in important ways.