My aim in this paper is to give a philosophical analysis of the relationship between contingently available technology and the knowledge that it makes possible. My concern is with what specific subjects can know in practice, given their particular conditions, especially available technology, rather than what can be known “in principle” by a hypothetical entity like Laplace’s Demon. The argument has two parts. In the first, I’ll construct a novel account of epistemic possibility that incorporates two pragmatic conditions: responsibility and (...) practicability. For example, whether subjects can gain knowledge depends in some circumstances on whether they have the capability of gathering relevant evidence. In turn, the possibility of undertaking such investigative activities depends in part on factors like ethical constraints, economical realities, and available technology. In the second part of the paper, I’ll introduce “technological possibility” to analyze the set of actions made possible by available technology. To help motivate the problem and later test my proposal, I’ll focus on a specific historical case, one of the earliest uses of digital electronic computers in a scientific investigation. I conclude that the epistemic possibility of gaining access to scientific knowledge about certain subjects depends (in some cases) on the technological possibility for making responsible investigations. (shrink)

Biological modalities (e.g., biological possibility, necessity and counterfactuality) play an important explanatory role in biological practice. However, biological modalities lack truth conditions and the inferential relationship between biological and other modalities is unclear. This thesis addresses these problems, first, by improving upon Daniel Dennett's Library of Mendel. Second, a family of modal logics is introduced. In the simplest model, states are interpreted as codons, the binary relation is interpreted as single substitution mutation and the valuation induces a partition of blocks (...) of codons that code for some amino acid. In addition, the proposed framework allows for a grading of biological possibility and captures various competing notions of biological possibility. Applications include a model checker and a lawless Lewis-style semantics for biological counterfactuals. In short, this thesis lays the groundwork for a theory of biological modalities. (shrink)

This paper offers a detailed criticism of different versions of modal scepticism proposed by Van Inwagen and Hawke, and, against these views, attempts to vindicate our reliance on thought experiments in philosophy. More than one different meaning of “ modal scepticism” will be distinguished. Focusing mainly on Hawke’s more detailed view I argue that none of these versions of modal scepticism is compelling, since sceptical conclusions depend on an untenable and, perhaps, incoherent modal epistemology. With a detailed account of modal (...) defeaters at hand I argue that Van Inwagen and Hawke’s scepticism is either groundless, or it leads to boundless and unacceptable modal scepticism. Additionally, I show that Hawke’s conception of analogical modal reasoning is problematic. Either his principle of similarity is arbitrary or it begs the question about modal scepticism. In contrast to Hawke’s restricted view of analogical modal reasoning, I present two examples of analogy-based modal justification of philosophically relevant possibility claims. My criticism of modal scepticism also shows that there is no good reason to insist on a sharp distinction between an unproblematic and a presumably dubious kind of modality. The upshot is that in absence of proper defeaters both Yablo-style conceivability and properly applied analogical reasoning are reliable guides to possibility, and also that modal justification comes in degrees. The proposed framework of defeaters of modal justification as well as the analysed examples of analogical modal reasoning trace out interesting new areas for further discussions. (shrink)

In discussing Disembodied Persons we need to confront two problems:A. Under what conditions would we consider that a person was present in the absence of the normal bodily cues?B. Could such circumstances arise?The first question may be regarded as epistemic and the second as metaphysical.

In discussing Disembodied Persons we need to confront two problems: A. Under what conditions would we consider that a person was present in the absence of the normal bodily cues? B. Could such circumstances arise? The first question may be regarded as epistemic and the second as metaphysical.

One reason for the recent attention to conceivability claims is to be found in the extended use of conceivability in philosophy of mind, and then especially in connection with zombie thought experiments. The idea is that zombies are conceivable; beings that look like us and behave like us in all ways, but for which “all is dark inside;” that is, for a zombie, there is no “what it is like.” There is no “what it is like” to be a zombie, (...) there is no “what it is like” for a zombie to feel pain, there is no “what it is like” for a zombie to taste, or feel, or smell something. They are creatures without consciousness. I am skeptical about the conceivability of zombies. That is not to say that I believe that there is some inherent contradiction to be found in the idea of zombies. Instead, I do not think that I am justified in believing that zombies are conceivable. The focus on justification is not common in the literature on conceivability, or for that matter in the literature on the possibility of zombies. Instead, the focus tends to be on trying to find out whether or not the notion of a zombie is contradictory. It is widely accepted in the literature on conceivability that the absence of a contradiction when conceiving of X is both necessary and sufficient for X to be conceivable. That might be true of ideal conceivability, but as I will argue below, ideal conceivability is not relevant to our (human) pursuit of knowledge and understanding. Further, as I will argue, once we focus on non-ideal conceivability the notion of justification, and degrees of justification comes into play. (shrink)

This paper advances the thesis that we can justifiably believe philosophically interesting possibility statements. The first part of the paper critically discusses van Inwagens skeptical arguments while at the same time laying some of the foundation for a positive view. The second part of the paper advances a view of conceivability in terms of imaginability, where imaginging can be propositional, pictorial, or a combination of the two, and argues that conceivability can, and often does, provide us with justified beliefs of (...) what is metaphysically possible. The notion of scenarios is developed, as is an account of how filling out scenarios can uncover a defeater or, in many cases, strengthen the justification for the relevant possibility statement. (shrink)

I survey a number of views about how we can obtain knowledge of modal propositions, propositions about necessity and possibility. One major approach is that whether a proposition or state of affairs is conceivable tells us something about whether it is possible. I examine two quite different positions that fall under this rubric, those of Yablo and Chalmers. One problem for this approach is the existence of necessary a posteriori truths and I deal with some of the ways in which (...) these authors respond to the problem, including the use of two-dimensional modal semantics. Conventionalism about modality offers a complementary approach to modal epistemology, prompting us to identify our knowledge of modal truths with our mastery of linguistic or conceptual conventions. Finally, I discuss an approach to modal epistemology deriving from David Lewis's work that seeks to identify structural features of the modal space over which necessity and possibility are defined. (shrink)

The method of thought experiments or possible cases is widespread in philosophy and elsewhere. Thought experiments come with variegated theoretical commitments. These commitments are risky. They may turn out to be false or at least controversial. Other things being equal, it seems preferable to do with minimal commitments. I explore exemplary ways of minimising commitments, focusing on modal ones. There is a near-consensus to treat the scenarios considered in thought experiments as metaphysical possibilities. I challenge this consensus. Paradigmatic thought experiments (...) do not have to come with a commitment to metaphysical possibilities. In the first section, I point out difficulties with the prevailing focus on metaphysical possibilities. In the second section, I present alternative formalisations of a paradigmatic thought experiment, the Gettier experiment. Gettier’s words leave open the kind of possibilities under consideration. The standard way of spelling out Gettier’s argument uses metaphysical possibilities. One alternative proposal uses nomological possibilities. A second one uses epistemic possibilities. My modest conclusion: as long as it is not established that a thought experiment requires a commitment to metaphysical modality, one should avoid such a commitment. My preferred way of doing so is to replace the commitment to one particular formalisation by a commitment to a disjunction of alternative formalisations. (shrink)

John Searle’s Chinese room argument is a celebrated thought experiment designed to refute the hypothesis, popular among artificial intelligence scientists and philosophers of mind, that “the appropriately programmed computer really is a mind”. Since its publication in 1980, the CRA has evoked an enormous amount of debate about its implications for machine intelligence, the functionalist philosophy of mind, theories of consciousness, etc. Although the general consensus among commentators is that the CRA is flawed, and not withstanding the popularity of the (...) systems reply in some quarters, there is remarkably little agreement on exactly how and why it is flawed. A newcomer to the controversy could be forgiven for thinking that the bewildering collection of diverse replies to Searle betrays a tendency to unprincipled, ad hoc argumentation and, thereby, a weakness in the opposition’s case. In this paper, treating the CRA as a prototypical example of a ‘destructive’ thought experiment, I attempt to set it in a logical framework, which allows us to systematise and classify the various objections. Since thought experiments are always posed in narrative form, formal logic by itself cannot fully capture the controversy. On the contrary, much also hinges on how one translates between the informal everyday language in which the CRA was initially framed and formal logic and, in particular, on the specific conception of possibility that one reads into the logical formalism. (shrink)

Thought-experiments in which one person divides into two have been important in the literature on personal identity. I consider three influential arguments which aim to undermine the force of these thought-experiments – arguments from David Wiggins, Patricia Kitcher and Kathleen Wilkes. I argue that all three fail, leaving us to face the consequences of splitting, whatever those may be.

Thought-experiments in which one person divides into two have been important in the literature on personal identity. I consider three influential arguments which aim to undermine the force of these thought-experiments – arguments from David Wiggins, Patricia Kitcher and Kathleen Wilkes. I argue that all three fail, leaving us to face the consequences of splitting, whatever those may be.

Modality and Anti-Metaphysics critically examines the most prominent approaches to modality among analytic philosophers in the twentieth century, including essentialism. Defending both the project of metaphysics and the essentialist position that metaphysical modality is conceptually and ontologically primitive, Stephen McLeod argues that the logical positivists did not succeed in banishing metaphysical modality from their own theoretical apparatus and he offers an original defence of metaphysics against their advocacy of its elimination. -/- Seeking to assuage the sceptical worries which underlie modal (...) anti-realism, McLeod provides an original contribution to essentialist epistemology, engaging with current debates about modality and suggesting that standard essentialist approaches to some issues in the philosophies of logic and language require revision. -/- This book offers valuable insights to professional philosophers, postgraduates and advanced undergraduates interested in metaphysics, philosophy of logic or the history of twentieth-century analytic philosophy. (shrink)

From the time of Descartes to about the 1960s, a certain epistemological idea dominated the philosophy of mind, namely the idea that theses about the relation between mind and body are, if true, a priori truths. Much of recent philosophy of mind is devoted to the question whether that idea is right. My research is largely an attempt to argue that some recent defenses of it are unsuccessful. ;For example, Physicalism is the metaphysical thesis that every actual psychological event, property, (...) or process is necessitated by some actual physical event, property, or process. Many philosophers believe that Physicalism is true. Until about the 1960s, those who believed it true typically believed that statements relating mind and body were a priori truths. Let us call this thesis A Priori Physicalism. Many philosophers nowadays believe, instead, that statements relating mind and body are only a posteriori truths. Let us call this thesis A Posteriori Physicalism. A number of philosophers have argued in recent years that A Posteriori Physicalism is unacceptable; on their view, Physicalists had better be A Priori Physicalists. My thesis examines the question whether that view is correct. ;I begin with a discussion of two influential arguments for the conclusion that Physicalists must be A Priori Physicalists. Chapter 1 addresses itself to an argument for the conclusion that if physicalism is true, every referring psychological expression is coreferential a priori with some referring physical expression. This argument is commonly called the Property Dualism Argument against Physicalism. I argue that the Property Dualism Argument rests on an ambiguous premise: on one reading it begs the question against A Posteriori Physicalism, on the other reading the conclusion of the Property Dualism Argument does not follow. ;Chapter 2 addresses itself to an argument of Frank Jackson's for the conclusion that Physicalists must have an a priori story to tell about how the physical nature of the actual world makes true the psychological nature of the actual world. I distinguish two ways in which this claim might be understood, and I argue that on neither way of understanding it does Jackson have a compelling argument for A Priori Physicalism. ;Finally, in Chapter 3 I turn to a more general discussion of the relation between conceivability and possibility, and its bearing on the dispute between A Priori and A Posteriori Physicalists. I focus in particular on a recent argument of David Chalmers' from the conceivability of so-called zombies to the conclusion that A Posteriori Physicalism is false. I argue that this argument fails to provide compelling reasons for rejecting A Posteriori Physicalism. I argue, first, that it misconstrues the relation between conceivability and possibility, and second, that it fails to establish that zombies are conceivable in the relevant sense. (shrink)

In this paper I challenge the core of David Chalmers' argument against materialism-the claim that "there is a logically possible world physically identical to ours, in which the positive facts about consciousness do not hold." First, I analyze the move from conceivability to logical possibility. Following George Seddon, I consider the case of a floating iron bar and argue that even this seemingly conceivable event has implicit logical contradictions in its description. I then show that the distinctions Chalmers employs between (...) primary and secondary intensions, and a priori and a posteriori entailment, break down upon close examination-with iron bars and with consciousness it is impossible to know where primary intensions end and secondary intensions begin. I extend this analysis of logical possibility to the famous zombie thought experiment and conclude not that a zombie world is logically impossible, but rather that, at present, the question is open. Finally, I show how a similar line of argument may be used to undermine the "Mary the color scientist" thought experiment as well. (shrink)

In this paper I argue that certain so-called conceivability arguments fail to show that a currently popular version of physicalism in the philosophy of mind is false. Concentrating on an argument due to David Chalmers, I first argue that Chalmers misrepresents the relation between conceivability and possibility. I then argue that the intuition behind the conceivability of so-called zombie worlds can be accounted for without having to suppose that such worlds are genuinely conceivable. I conclude with some general remarks about (...) the nature of conceivability. (shrink)

In this dissertation, I evaluate whether conceivability can be regarded as an epistemic guide to possibility.