Journal of the History of Philosophy

This edited collection, which grows out of a 2013 British Society for the History of Philosophy conference on the topic of "the actual and the possible" at which early versions of some of the nine essays were presented, explores various episodes in the history of modern metaphysics of modality. It is broad (ranging from the seventeenth century to the twentieth century and beyond) and self-consciously eclectic in its coverage of figures and issues. There are chapters dealing with Spinoza, Wolff, Leibniz and Kant, Kant (on his own), Hegel, Russell, Meinong and Łukasiewicz, Heidegger, and Quine (in relation to the views of Kripke, Lewis, and Fine).

Some of the chapters are synoptic, providing a big picture account of the evolution of a given philosopher's views on modality; others focus on fine-grained details, arguments, and implications; others aim at exploring agreements and disagreements between philosophers; and yet others combine various approaches. Given its length and limited ambitions, it understandably omits many philosophers whose views on modality are of interest.

One might worry that the chronological breadth and eclecticism would preclude cohesion, and, admittedly, it is sometimes hard to find much common ground between some of the accounts of modality (consider, for example, the large gulf that separates, say, Quine from Spinoza, Hegel, and even Kant). That said, the volume's focus on questions about the metaphysics of modality gives some modest unity to the manifold. These questions include the following: How are modal notions like possibility, necessity, and actuality to be interpreted? What are the truth-conditions of claims involving modal terms (if indeed they have truth-values)? Can sense be made of de re modal predication? If so, is de re modality primitive, or is it underwritten by essentialist commitments that cannot be reduced to modal ones?

Sinclair's introduction—along with the volume's title—indicates that questions regarding actuality and its relationship to possibility are of particular importance for the collection. Chapters 1, 3, 4, 5, and 8 all consider (directly or indirectly) whether the actual is in some sense ontologically prior to, or privileged over, the possible. We learn that, each in their own way, Spinoza, Leibniz, and Kant prioritize actuality, taking the possible to be grounded in the actual (indeed, in actual features of God, for Spinoza, Leibniz, and the pre-critical Kant). By contrast, Heidegger prioritizes possibility, while Hegel, for his part, maintains an essential interconnection between actuality, possibility, and necessity. A related but distinguishable set of questions concerns possibilia—whether there are unrealized possibilia and if so what sort of being they have. Such questions receive varying amounts of attention in the chapters that cover Spinoza, Leibniz and Kant, Russell, Meinong, and Heidegger.

In order to provide background and motivation for the volume, Sinclair's introduction highlights some key moments in the history of the metaphysis of modality, up to the present day. The story starts with Aristotle, who advocated a "statistical" account of modality—the possible is that which is actual at some point in time, the necessary is always actual, etc.—in conjunction with a metaphysics of essences and this-worldly potentialities. Leibniz eschewed the statistical view, instead invoking possible worlds that exist in God's understanding, and allowing, unlike Aristotle, for unrealized possibilities. The mid-twentieth century saw an appropriation of possible worlds talk, though with disagreement about whether and what sort of ontological commitment such talk incurs. Recently, the pendulum has partly shifted back to Aristotle, with some accounting for de re modal predication in terms of essences.

While this narrative is useful, it glosses over a lot—for example, everything that happens between Leibniz and the mid-twentieth century (including, among other things, Russell's fin de siècle exposition of Leibniz's doctrine of possible worlds). In making Aristotle and Leibniz opposite poles on the pendulum, it leaves unclear where to place someone like Spinoza, who vehemently eschews Leibnizian possible worlds and...