Damian Aleksiev

The papers in The Epistemology of Grounding investigate how we can know what grounds what and discover metaphysical explanations. Questions about reality’s metaphysical structure – and thus what grounds what – are ubiquitous across philosophy. This volume contains new insight into how we can answer such questions and thus into how to better understand reality’s structure. Its expert contributions include new work on conceptualism and the logic of grounding, abduction and inference to the best explanation, grounding in the sciences, knowledge of grounding on the basis of essence and identity, and an account of perceptual knowledge of grounding. Together, these contributions address an urgent need in the literature and will interest a broad philosophical audience interested in grounding and its epistemology, as well as metaphysics and its methodology more generally.

This essay outlines a hierarchical framework of Reality that allows for degrees of Reality. I use Reality (with a capital “R”) to designate reality in a primitive, metaphysical sense. Reality, grounding, and essence are the key elements of the framework presented here. I assume that Reality must have a fundamental level and all fundamental phenomena must be Real. Moreover, I postulate that everything non-fundamental is ultimately grounded in the fundamental Real. But what about the Reality of the non-fundamental? I argue that it is possible for non-fundamental phenomena to be Real, Unreal, or Semi-Real. The framework developed here accommodates these possibilities and illuminates them using the notion of essence. I argue that the essential nature of a phenomenon determines its degree of Reality. The framework does not assume that Reality must have degrees but only that it may have degrees. Its theoretical attractiveness consists in its ability to accommodate many diverse intuitions about grounding, help us better understand and classify theories about grounding, and illuminate Reality and its possible degrees.

This paper presents a novel argument against one theoretically attractive form of panpsychism. I argue that “idealist panpsychism” is false since it cannot account for spacetime’s structure. Idealist panpsychists posit that fundamental reality is purely experiential. Moreover, they posit that the consciousness at the fundamental level metaphysically grounds and explains both the facts of physics and the facts of human consciousness. I argue that if idealist panpsychism is true, human consciousness and the consciousness at the fundamental level will have the same metrical structure. However, as I demonstrate, human consciousness does not exhibit the same metrical structure as spacetime. Consequently, the idealist panpsychist faces an explanatory gap between the fundamental consciousness she posits and spacetime. Idealist panpsychism is incompatible with the existence of such an explanatory gap. Thus, idealist panpsychists must close this explanatory gap (which I argue they lack the resources to do), or idealist panpsychism is false.

I define two metaphysical positions that anti-physicalists can take in response to Jonathan Schaffer’s ground functionalism. Ground functionalism is a version of physicalism where explanatory gaps are everywhere. If ground functionalism is true, arguments against physicalism based on the explanatory gap between the physical and experiential facts fail. In response, first, I argue that some anti-physicalists are already safe from Schaffer’s challenge. These anti-physicalists reject an underlying assumption of ground functionalism: the assumption that macrophysical entities are something over and above the fundamental entities. I call their position “lightweight anti-physicalism.” Second, I go on to argue that even if anti-physicalists accept Schaffer’s underlying assumption, they can still argue that the consciousness explanatory gap is especially mysterious and thus requires a special explanation. I call the resulting position “heavyweight anti-physicalism.” In both cases, the consciousness explanatory gap is a good way to argue against physicalism.

Panpsychists aspire to explain human consciousness, but can they also account for the physical world? In this paper, I argue that proponents of a popular form of panpsychism cannot. I pose a new challenge against this form of panpsychism: it faces an explanatory gap between the fundamental experiences it posits and some physical entities. I call the problem of explaining the existence of these physical entities within the panpsychist framework “the missing entities problem.” Spacetime, the quantum state, and quantum gravitational entities constitute three explanatory gaps as instances of the missing entities problem. Panpsychists are obliged to solve all instances of the missing entities problem; otherwise, panpsychism cannot be considered a viable theory of consciousness.