 Cameron applies considerations of theoretical parsimony to the case of infinite chains of ontological dependence. While allowing that there is no impossibility in an infinite regress of things, each ontologically dependent on the next, Cameron argues that we can still have reason to reject such a theory on parsimony considerations. Cameron (2008, 12) says that what needs to be explained is the existence of each dependent entity; and while he allows that in an infinitely descending chain of ontologically dependent entities, there is an explanation for why each dependent entity exists, there is no single explanation for why all the dependent entities exist. Whereas if there is a collection of fundamental entities on which all the dependent entities ultimately depend, these fundamental entities provide a single unified explanation for why every dependent entity exists. Either way, everything that needs to be explained gets explained, but Cameron says we have reason to prefer the unified explanation over the infinitely many disparate explanations, since it is in general a theoretical virtue to provide a unified explanation. For example, a physical theory that postulates one unified force to explain all phenomena would, other things being equal, be preferable to one that postulates four fundamental forces—gravity, electromagnetism, strong nuclear, and weak nuclear—even if the two theories explain exactly the same phenomena. (Orilia (2009) argues, contra Cameron, that there is no unified explanation provided by Metaphysical Foundationalism over theories with infinite ontological descent.)