Teresa Robertson Ishii

I explore options for a plenitudinarian solution to the Paradox of Flexible Origin Essentialism, taking as my unlikely starting point the views of Sarah-Jane Leslie, who holds that if plenitudinarianism is true, then there is in fact no paradox to be solved, only the illusion of one. The first three sections are expository: Sect. 1 on plenitudinarianism, Sect. 2 on the paradox, and Sect. 3 on Leslie’s views about how plenitudinarianism bears on the paradox. In Sect. 4, I reject the contention that there is no paradox and critically explore three options for a plenitudinarian solution. In Sect. 5, I argue that the plenitudinarian ought to endorse a fourth option. In Sect. 6, I consider an objection. I endorse neither plenitudinarianism nor its denial; the main aim of the paper is to argue that for one who does endorse plenitudinarianism, the best solution to the Paradox of Flexible Origin Essentialism is clear.

We defend hylomorphism against Maegan Fairchild’s purported proof of its inconsistency. We provide a deduction of a contradiction from SH+, which is the combination of “simple hylomorphism” and an innocuous premise. We show that the deduction, reminiscent of Russell’s Paradox, is proof-theoretically valid in classical higher-order logic and invokes an impredicatively defined property. We provide a proof that SH+ is nevertheless consistent in a free higher-order logic. It is shown that the unrestricted comprehension principle of property abstraction on which the purported proof of inconsistency relies is analogous to naïve unrestricted set-theoretic comprehension. We conclude that logic imposes a restriction on property comprehension, a restriction that is satisfied by the ramified theory of types. By extension, our observations constitute defenses of theories that are structurally similar to SH+, such as the theory of singular propositions, against similar purported disproofs.

In this paper, I examine the case that has been made for origin essentialism and find it wanting. I focus on the arguments of Nathan Salmon and Graeme Forbes. Like most origin essentialists, Salmon and Forbes have been concerned to respect the intuition that slight variation in the origin of an artifact or organism is possible. But, I argue, both of their arguments fail to respect this intuition. Salmon's argument depends on a sufficiency principle for cross-world identity, which should be rejected, if - as Salmon concedes - a given artifact might have been originally made from slightly different material. Similarly, Forbes's argument succeeds only if essentially the same argument can be used to establish a claim that - by his own admission - is too strong, namely that no variation, however slight, in an organism's origin is possible.

Abstract David Sobel (2001) objects to Bernard Williams's internalism, the view that an agent has a reason to perform an action only if she has some motive that will be served by performing that action. Sobel is an unusual challenger in that he endorses neo-Humean subjectivism, ?the view that it is the agent's subjective motivational set that makes it the case that an agent does or does not have a reason to φ? (219). Sobel's objection in fact arises from this very commitment. Internalism, he says, is incompatible with the best subjectivist accounts of reasons for action?accounts that suggest that there are what he calls fragile reasons and perhaps also superfragile ones, both of which allegedly provide for counterexamples to internalism. I argue that such reasons do not in fact threaten internalism. I then briefly explore whether internalism is vulnerable to a related charge?that it commits the conditional fallacy

This is a three paper dissertation. ;for paper 1. Quine held that quantifying into modal contexts is illegitimate. It is sometimes thought that if he is right about this, then essentialist claims make no sense. Perhaps as a consequence of this thought together with the current prominence of essentialist views, there have been two good fairly recent attacks on Quine's argument against quantifying into modal contexts: Neale's revival of Smullyan's points and Kaplan's paper "Opacity". I first argue that Quine's view is not refuted by Neale or Kaplan. I next explain that nonetheless, essentialists need not surrender in the face of Quine's injunction against quantifying in. Quine's work does not rule out the intelligibility of essentialist theses; it does however issue a challenge to explain the mysterious notion of metaphysical necessity. ;Abstract for paper 2. I examine the case that has been made for origin essentialism and find it wanting. I focus on the arguments of Salmon and Forbes. Like most origin essentialists, they have been concerned to respect the intuition that slight variation in the origin of an artifact or organism is possible. But, I argue, both of their arguments fail to respect this intuition. Salmon's argument depends on a sufficiency principle for crossworld identity, which should be rejected, if---as Salmon concedes---a given artifact might have been originally made from slightly different material. Similarly, Forbes's argument succeeds only if essentially the same argument can be used to establish a claim that---by his own admission---is too strong, namely that no variation, however slight, in an organism's origin is possible. ;Abstract for paper 3. Chisholm's Paradox suggests that origin essentialism is incompatible with the view that some variation in the origin of a given thing is possible. Since the latter view is strongly supported by intuition, origin essentialists have been eager to offer solutions to the paradox. In this paper I look at three allegedly different solutions to the paradox: Forbes's, Salmon's, and Lewis's. I give new criticisms of Forbes's view and offer new defenses of what I call the "Salmon-Lewis solution"

The distinction between essential versus accidental properties has been characterized in various ways, but it is currently most commonly understood in modal terms: an essential property of an object is a property that it must have, while an accidental property of an object is one that it happens to have but that it could lack. Let’s call this the basic modal characterization, where a modal characterization of a notion is one that explains the notion in terms of necessity/possibility. In the characterization just given of the distinction between essential and accidental properties, the use of the word “must” reflects the fact that necessity is invoked, while the use of the word “could” reflects that possibility is invoked. The notions of necessity and possibility are interdefinable: to say that something is necessary is to say that its negation is not possible; to say that something is possible is to say that its negation is not necessary; to say that an object must have a certain property is to say that it could not lack it; and to say that an object could have a certain property is to say that it is not the case that it must lack it.