The glass vase on my desk is fragile. It should be handled with care because it it is likely to shatter or crack if it is knocked, dropped, or otherwise treated roughly. The vase has certain dispositions, for example the disposition to shatter when dropped. But what is this disposition? It seems on the one hand to be a perfectly real property, a genuine respect of similarity common to glass vases, china cups, ancient manuscripts, and anything else fragile. Yet on (...) the other hand my vase's disposition seems mysterious, "ethereal" (as Nelson Goodman (1954) put it) in a way that, say, its size and shape properties are not. For my vase's disposition, it seems, has to do only with its possibly shattering in certain conditions, conditions which I hope will never be realized. In general, it seems that nothing about the actual behavior of an object is ever necessary for it to have the dispositions it has. Many objects differ from each other with respect to their dispositions in virtue of their merely possible behavior, and this is a mysterious way for objects to differ. (shrink)

As we understand them, dispositions are relatively uncontroversial 'predicatory' properties had by objects disposed in certain ways. By contrast, powers are hypothetical 'ontic' properties posited in order to explain dispositional behaviour. Chapter 1 outlines this distinction in more detail. Chapter 2 offers a summary of the issues surrounding analysis of dispositions and various strategies in contemporary literature to address them, including one of our own. Chapter 3 describes some of the important questions facing the metaphysics of powers including why they're (...) worth positing, and how they might metaphysically explain laws of nature and modality. (shrink)

This paper responds to the contributions by Alexander Bird, Nathan Wildman, David Yates, Jennifer McKitrick, Giacomo Giannini & Matthew Tugby, and Jennifer Wang. I react to their comments on my 2015 book Potentiality: From Dispositions to Modality, and in doing so expands on some of the arguments and ideas of the book.

Dispositionalism about modality is the view that metaphysical modality is a matter of the dispositions possessed by actual objects. In a recent paper, David Yates has raised an important worry about the formal adequacy of dispositionalism. This paper responds to Yates’s worry by developing a reply that Yates discusses briefly but dismisses as ad hoc: an appeal to a ’plenitude of powers’ including such powers as the necessarily always manifested power for 2+2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} (...) \begin{document}$$2+2$$\end{document} to be 4. I argue that the reply is not ad hoc at all, by defending the metaphysics of dispositions that should underly it. I then argue, first, that a proper understanding of dispositions’ degrees provides us with an argument for such necessarily always manifested dispositions; second, that all the natural attempts to block that argument can be resisted without being ad hoc; and third, that pragmatic considerations explain our intuitive resistance to the ascription of necessarily always manifested dispositions. Dispositionalism can be formally adequate after all. (shrink)

According to the modal account of propositional apriority, a proposition is a priori if it is possible to know it with a priori justification. Assuming that modal truths are necessarily true and that there are contingent a priori truths, this account has the undesirable consequence that a proposition can be a priori in a world in which it is false. Epistemic two-dimensionalism faces the same problem, since on its standard interpretation, it also entails that a priori propositions are necessarily a (...) priori. In response to this problem, Chalmers and Rabern propose an alternative conception of propositional apriority as well as two-dimensional truth-conditions for apriority statements. Their proposal is also supposed to avoid another problem for the modal account, namely that it entails the existence of false instances of ‘φ iff actually φ’. I discuss Chalmers and Rabern’s account and point out a number of problems with it. I then develop my own account of propositional apriority that solves the problems in question, that can be accepted by friends and foes of two-dimensionalism alike, and that is also neutral with respect to the question of how one construes the objects of propositional apriority. (shrink)

Dispositions (powers, potentialities) have become popular in metaphysics in recent years, and some of their proponents are advertising them as the best metaphysical grounds for modality. This project has a logical as well as an ontological side: dispositionalists offer modal and counterfactual semantics that make no use of possible worlds. I argue that, as a result of their counterfactual semantics, dispositionalists are in fact committed to entities that play the same theoretical role as possible worlds. Roughly, the claim is that (...) certain counterfactuals (ones that concern 'very large' states) force the dispositionalist to posit world-sized states that play the theoretical role of worlds. As a result, dispositionalists can (and perhaps should) make use of the mainstream framework (Kripke frames and the Lewis–Stalnaker counterfactual semantics) even if they ground all modal facts in dispositions. (shrink)

According to dispositionalism about modality, a proposition <p> is possible just in case something has, or some things have, a power or disposition for its truth; and <p> is necessary just in case nothing has a power for its falsity. But are there enough powers to go around? In Yates (2015) I argued that in the case of mathematical truths such as <2+2=4>, nothing has the power to bring about their falsity or their truth, which means they come out both (...) necessary and not possible. Combining this with axiom (T), it is easy to derive a contradiction. I suggested that dispositionalists ought to retreat a little and say that <p> is possible just in case either p, or there is a power to bring it about that p, grounding the possibility of mathematical propositions in their truth rather than in powers. Vetter’s (2015) has the resources to provide a response to my argument, and in her (2018) she explicitly addresses it by arguing for a plenitude of powers, based on the idea that dispositions come in degrees, with necessary properties a limiting case of dispositionality. On this view there is a power for <2+2=4>, without there being a power to bring about its truth. In this paper I argue that Vetter’s case for plenitude does not work. However, I suggest, if we are prepared to accept metaphysical causation, a case can be made that there is indeed a power for <2+2=4>. (shrink)

Jennifer McKitrick offers an opinionated guide to the philosophy of dispositions. In her view, when an object has a disposition, it is such that, if a certain type of circumstance were to occur, a certain kind of event would occur. Since this is very common for this to be the case, dispositions are an abundant and diverse feature of our world.