Journals

Confronting the threat of a Spinozistic necessitarianism, Leibniz insists that not all possible substances are compossible—that they can't all be instantiated together—and thus that not all possible worlds are compossible—that they can't all be instantiated together. While it is easy to appreciate Leibniz's reasons for embracing this view, it has proven difficult to see how his doctrine of incompossibility might be reconciled with the broader commitments of his larger philosophical system. This essay develops, in four sections, a novel solution to the "puzzle of incompossibility." The first section frames the difficulty more carefully and briefly argues that the two dominant strategies developed by Leibniz's commentators fail to solve it fully insofar as they require simply abandoning one or another of its motivating commitments. The second and third sections show how Leibniz's guiding analogy of a geometrical packing or tiling problem may be applied to solve the puzzle of incompossibility in the context of finite and infinite worlds composed of extended corporeal substances. Finally, the fourth section shows how the strategy of Leibniz's packing analogy might be applied even in the context of a thoroughly idealist metaphysics in which the only true substances are nonextended, mindlike "monads." The essay concludes by drawing some connections between Leibniz's thinking about the puzzle of incompossibility and the development of his views concerning the status of corporeal substances and extended bodies.

Rousseau's thought is marked by an optimism and a pessimism that each evoke, at least in the right mood, a feeling of recognition difficult to suppress. We have an innate capacity for virtue, and with it freedom and happiness. Yet our present social conditions instill in us a restless craving for superiority, which leads to vice, and with it bondage and misery. Call this the "thesis of possible goodness": that while human psychology is such that men become wicked under the conditions in which we now find them, nevertheless men would be, or have been, good under other conditions. It is surprisingly difficult, or at least surprisingly complicated, however, to articulate even a possible psychology that would explain the thesis of possible goodness. Interpretations of Rousseau, even several to which the author of this essay is highly indebted, have not fully engaged, I think, with the complications. This essay tries to reconstruct psychological principles that would explain the thesis and that are at least consistent with what Rousseau otherwise says on the subject. Much of the value of this exercise, however, lies not in the particulars of the resulting psychology but rather in the depth of the tension between Rousseau's optimism and his pessimism that it reveals.

This essay examines the thought that our right actions have moral worth only if we perform them for the right reasons. It argues against the view, often ascribed to Kant, that morally worthy actions must be performed because they are right and argues that Kantians and others ought instead to accept the view that morally worthy actions are those performed for the reasons why they are right. In other words, morally worthy actions are those for which the reasons why they were performed (the reasons motivating them) and the reasons why they morally ought to have been performed (the reasons morally justifying them) coincide. The essay calls this the Coincident Reasons Thesis and argues that it provides plausible necessary and sufficient conditions for morally worthy action, defending the claim against proposed counterexamples. It ends by showing that the plausibility of the thesis, which it argues is largely independent of any particular ethical standpoint, gives us some reason to doubt a class of ethical theories that includes utilitarianism.