Date of Degree


Document Type


Degree Name





David Papineau

Committee Members

Michael Devitt

Jonathan Schaffer

Subject Categories

Epistemology | Metaphysics


Modal Epistemology, Modality, Essence, Explanation, Natural Kinds, A Priori


The primary aim of this project is to put forward a novel account of knowledge of metaphysical modality. I call this the “Essentialist Superexplanatory” account of modal knowledge, because it relies on the following two main theses: (a) knowledge of metaphysical necessity is grounded in knowledge of essence; and (b) essences are properties, sets of properties, or mechanisms, having distinctive explanatory powers for how things are. While thesis (a) is quite popular in the current debates, mostly thanks to Kit Fine’s recent work in modal metaphysics, thesis (b) introduces an original brand of essentialism. As I show by means of various examples involving both kinds and individuals, it seems fruitful to think of essences as underlying cores which cause a multitude of typical properties of things. Because of this, essences explain why those properties consistently co-occur in those kinds and individuals—in this sense essences are “superexplanatory” for how things are.

This account of essence has crucial consequences at the epistemological level. For essences are things that we discover empirically, typically via scientific investigation. Although the discovery of essence has been held to be a central task of philosophy since Aristotle introduced it, essences have also been often disparaged in contemporary debates as hidden mysterious entities, or some sort of relic of a pre-scientific era. The Essentialist Superexplanatory account aims to overcome those prejudices and show that there is a scientifically grounded way to clarify in what sense essential properties constitute the “nature” of things. If this is correct, the epistemology of central cases of metaphysical necessity is much easier than many have thought. For we infer what is necessarily true of things from our knowledge of what is essential to things.

The Essentialist Superexplanatory account owes much to the work of Saul Kripke in the 1970s and 1980s; especially to his main insight that modal knowledge proceeds inferentially, from premises concerning the actual makeup of the world to conclusions about the non-actual and necessary. In fact, a further crucial component of my account is a Kripkean bridge-principle connecting essence and necessity, both at the constitutive-metaphysical level and at the epistemic-normative level. In its simplest formulation, this bridge-principle says that if something is essentially in a certain way, then it is (metaphysically) necessarily that way: “If x is essentially F, then necessarily x is F”.

Also importantly, from a methodological point of view, the Essentialist Superexplanatory account prioritizes the investigation of modal metaphysics, and of essence in particular, for elucidating knowledge of modality. I call it accordingly a “modal-metaphysics-first” approach to modal knowledge and oppose it to the more traditional “means-first” approach that has dominated the literature in the past twenty years or so.

As to the structure of the work, this dissertation is not a traditional monograph. Instead, it is composed of three related but independent research articles, each with its own abstract, plus a final Appendix. Here is a brief summary of each piece.

In the first article, “Two Notions of Metaphysical Modality”, I argue that Conceivability-theory as cashed out by David Chalmers does not help cast light on knowledge of genuine metaphysical modality as traditionally pictured by Kripke. Instead, Chalmers’ conceivability only safely ranges over logical-conceptual possibility under standards of ideal coherence. I show how, at bottom, Chalmers and Kripke are operating with two different, incompatible notions of metaphysical modality. This article was published in Synthese (“online first”) on February 1st, 2018:

In the second article, “Putting Modal Metaphysics First”, I present my metaphysics-first approach to modal knowledge against the dominant tradition and lay out my positive “Essentialist Superexplanatory” account. I use chemical kinds as a case-study and illustrate how essences cause and explain the many properties that are typically shared by all the instances of a kind. Knowing what is essential to (the instances of) the kind in this sense is the basis for knowing what is necessary for (the instances of) the kind. This article was published in Synthese (“online first”) on May 29th, 2018:

In the third article, “Essentialist Constraints on Counterfactual Knowledge”, I turn to Timothy Williamson’s Counterfactual-theory. I discuss a number of problems that have been raised for it by the recent literature and argue that those all ultimately trace back to the failure to elucidate the proper normative constraints on modal reasoning. By means of various examples, I show how the Essentialist Superexplanatory account instead clarifies such constraints, and thus constitutes a better account of how we gain modal knowledge. This article is in preparation for the volume “Modal Thinking”, edited by A. Vaidya and D. Prelevic, forthcoming with Oxford University Press.

Finally, in the Appendix, I discuss a category of potentially problematic cases for the Essentialist Superexplanatory account, namely what I call the “purely a priori metaphysical necessities”. I lay out a pluralistic picture of modal space which distinguishes different kinds of necessity, based on their source. Specifically, it distinguishes between two kinds of metaphysical necessities: the “general” vs. the “distinctively” metaphysical necessities. I show how this helps us handle the a priori cases, and sketch a possible way forward for modal epistemology.