Michael Della Rocca

in his characteristically generous and searching discussion of my book, Spinoza, Daniel Garber rightly points out that I structure my interpretation of Spinoza’s system around the principle of sufficient reason. This is the principle that, as I and others sometimes put it, each fact has an explanation and is thus not brute, or the principle that each thing has an explanation. The ‘or’ will soon be important. Indeed, it might seem that I am too focused on the PSR—certainly I seem that way to Garber1—for I seek to use the PSR to unlock any number of problems that interpreters of Spinoza have faced over the last three centuries. Garber does a great job of conveying the range of uses to which I put the PSR..

Joseph Almog’s elegant and concise monograph, What am I?, simultaneously advances a new interpretation of Descartes’ dualism and offers a powerful articulation of the bearing of essentialist metaphysics on the mind-body problem. Some may object to Almog’s endeavor to see Descartes so much in light of recent, Kripkean developments in metaphysics. Some may object to this, but not me. The study of the history of philosophy is tough, and we cannot afford to neglect any potential source of insight. Some may object to Almog’s tying his original development, and criticism, of Kripkean metaphysics to the—let’s face it—often obscure views of someone writing more than three centuries ago. Some might say: why not forget the history and just take on the real issues directly? Some might say this, but not me. Like the study of the history of philosophy, philosophy itself is tough and we cannot afford to neglect any potential way of making progress, even if that way comes from one of our remote philosophical ancestors. Indeed, I would say that the distinction between doing philosophy and studying its history is not all that sharp, if it exists at all. This is one of the important lessons of which Almog’s book reminds us. Some may object to Almog’s relatively sparse attention to the details of Descartes’ texts and his non-existent attention—at least explicitly—to any secondary literature on Descartes. Some may object to this, but, again, not me. While there are some distinctions that Almog attributes to Descartes that he might have endeavored to tie more closely to Descartes’ texts, Almog’s relatively free-wheeling approach has the benefit of allowing him to articulate, and us to see, the positions he develops more starkly and clearly.

I argue that the key motivation for the essentialist is that modal intuitions, such as "Humphrey might have won", are not to be explicated in terms of persons in other possible situations who are similar to the actual Humphrey. However, because of a need to preserve the necessity of identity, the essentialist must claim that certain other intuitions (such as "Hesperus might not have been Phosphorus") have to be understood in terms of similarity (as in Kripke) or have to be rejected (as in Yablo). This move leads to ineliminable doubts about the essentialist's rejection of similarity, and so it leads to an undermining of the motivation for essentialism itself.