As it is presently employed, grounding permits grounding many things from one ground. In this paper, I show why this is a mistake by pushing for a uniqueness principle on grounding. After arguing in favor of this principle, I say something about it and kinds of grounding, discuss a similar principle, and consider its import on a formal feature of grounding, ontology, and ontological simplicity.

The main idea of this thesis is multi-descriptional physicalism. According to it, only physical entities are elements of our ontology, and there are different ways to describe them. Higher-level vocabularies (e.g., mental, neurological, biological) truly describe reality. Sentences about higher-level entities are made true by physical entities. Every chapter will develop multi-descriptional physicalism or defend it from objections. In chapter 1, I will propose a new conceptual reductive account that conceptually reduces higher-level entities to physical entities. This conceptual reductive account (...) combines resources from Heil’s truthmaker theory and either a priori physicalism or a posteriori physicalism. In chapter 2, I apply this conceptual reductive account to various debates. Physicalism, the multiple-realisability argument, the prototype theory of concepts, and truthmaker explanations will be discussed. In chapter 3, I will argue that a major aim of metaphysics should be to discover which entities are fundamental and explain why they suffice for the existence of derivative entities. In chapter 4, I will propose a new way to explain why sentences apparently about composite objects are true even though there are no composite objects. It combines resources from Cameron’s truthmaker theory and van Inwagen’s paraphrase strategy. In chapter 5, I will argue that the intuition that the mind and the body are very different does not show that the mind is distinct from the body. This intuition can be explained away by mentioning our dispositions to give non-physical explanations when we are ignorant of physical facts. In chapter 6, I will examine two arguments for the existence of a metaphysically independent level, and I will argue that only a modified version of one of them succeeds. I will argue that methodological principles support the view that there is a metaphysically independent level. (shrink)

"Ontology" focuses on three ways ground and ontology are said to relate. One way involves ground's ability to provide a safe and sane way of admitting certain kinds of things in our theories. Another way involves ground's ability to show how we should measure ontological simplicity. And a third way involves ground's ability to restrict what things or kinds of things can depend on other things or kinds.

A raft of new philosophical problems concerning truth have recently been discovered by several theorists. These problems concern the question of how ascriptions of truth are to be grounded. Most previous commentators have taken the problems to shed light on the theory of ground. In this paper, I argue that they also shed light on the theory of truth. In particular, I argue that the notion of ground can be deployed to clearly articulate one strand of deflationary thinking about truth, (...) according to which truth is “metaphysically lightweight.” I offer a ground-theoretic explication of the lightness of truth and show how it yields a novel solution to the problems concerning how truth is grounded. So, the theory of truth and the theory of ground interact fruitfully: we can apply the notion of ground to offer a clear explication of the deflationist claim that truth is “metaphysically lightweight” that both captures the motivations for that claim and solves the problems. (shrink)

According to the Ontological Innocence Thesis (OIT), grounded entities are ontologically innocent relative to their full grounds. I argue that OIT entails a contradiction, and therefore must be discarded. My argument turns on the notion of “groundmates,” two or more numerically distinct entities that share at least one of their full grounds. I argue that, if OIT is true, then it is both the case that there are groundmates and that there are no groundmates. Therefore, so I conclude, OIT is (...) false. Moreover, once we have seen why OIT is false, only three heterodox views about reality's structure remain. So this paper’s second conclusion is that, even after we have discarded OIT, we are in for an additional surprise. (shrink)

Many philosophers take purportedly logical cases of ground ) to be obvious cases, and indeed such cases have been used to motivate the existence of and importance of ground. I argue against this. I do so by motivating two kinds of semantic determination relations. Intuitions of logical ground track these semantic relations. Moreover, our knowledge of semantics for first order logic can explain why we have such intuitions. And, I argue, neither semantic relation can be a species of ground even (...) on a quite broad conception of what ground is. Hence, without a positive argument for taking so-called ‘logical ground’ to be something distinct from a semantic determination relation, we should cease treating logical cases as cases of ground. (shrink)

Discussion of the relevance of grounding to substantiveness, theory-choice, and “location problems” in metaphysics.

Truthmaker theorists often express their core commitment by saying that truth is grounded in being, and grounding theorists often take truthmaking to be a paradigm case of grounding. But I will argue that truthmaking is not a case of grounding. What is crucial for understanding truthmaking is not grounding but rather meaning (in a broad sense including reference). Truth is still constrained by how things are, so even if (so‐called) truthmakers don't play a role in grounding truths, the methodological program (...) of truthmaker theory survives. Here I lay out my understanding of truth and truthmaking, and distinguish two conceptions of grounding. I argue that truthmaking is not plausibly seen as a case of grounding on either conception. I argue further that treating truthmaking as grounding threatens to violate a plausible irreflexivity principle, and makes trouble for the view that grounding is transitive. I then suggest that there is no genuine relation of truthmaking (which there would have to be if it were a true case of grounding). Finally, I show how the core insights of truthmaker theory are preserved by the understanding of truthmaking that I favor. (shrink)

No. More carefully: apparently not. [This piece was published in the Routledge Handbook of Metaphysical Ground (2020), edited by Michael J. Raven with the title "Anti-Skeptical Rejoinders", pp. 180-193].

Traditional rationalist approaches to a priori epistemology have long been looked upon with suspicion for positing a faculty of rational intuition capable of knowing truths about the world apart from experience. Conceptualists have tried to fill this void with something more empirically tractable, arguing that we know a priori truths due to our understanding of concepts. All of this theorizing, however, has carried on while neglecting an entire cross section of such truths, the grounding claims that we know a priori. (...) Taking a priori grounding into account poses a significant challenge to conceptualist accounts of a priori knowledge, as it is unclear how merely understanding conceptual connections can account for knowledge of grounding. The fact that we do know some grounding truths a priori, then, is a significant mark in traditional rationalism’s favor, and the next frontier for those who aim to eliminate the mystery surrounding a priori knowledge. (shrink)

General discussion of grounding, including its formal features, relations to other notions, and applications. (Originally published 2014; revised 2021).

A natural proposal for the grounds of negative existential truths, such as that Vulcan does not exist, states that these truths are grounded in the totality truth affirming the existence of every existent thing together with the truth that they are all. In this paper I will put forward three objections to straightforward formulations of this idea, and argue that a change in the usual grammar of grounding claims, allowing for pluralities of sentences to express not only grounds, but also (...) groundees, is effective in making the account immune to the objections raised. (shrink)

According to Humeanism about the laws, the laws of nature are nothing over and above certain kinds of regularities about particular facts. Humeanism has often been accused of circularity: according to scientific practice laws often explain their instances, but on the Humean view they also reduce to the mosaic, which includes those instances. In this paper I formulate the circularity problem in a way that avoids a number of controversial assumptions routinely taken for granted in the literature, and against which (...) many extant responses are therefore ineffective. I then propose a solution that denies the alleged Humean commitment that laws are explained by their instances. The solution satisfies three desiderata that other solutions don’t: it provides independent motivation against the idea that Humean laws are explained by their instances; it specifies the sense in which Humean laws are nonetheless “nothing over and above” their instances; and it gives an alternative account of what does explain the laws, if not their instances. This solution, I will argue, is not only the simplest but also the oldest one: it appeals only to tools and theses whose first appearance predates the earliest statements of the circularity problem itself. (shrink)