In his work on personal identity, Derek Parfit makes two revolutionary claims: firstly, that personal identity is not what matters in survival; and secondly, that what does matter is relation R. In this article I demonstrate his position here to be inconsistent, with the former claim being defensible only in case the latter is false. Parfit intends his famous fission argument to establish the unimportance of identity – a conclusion disputed by, among others, Mark Johnston. My approach is to critically (...) assess their debate, focusing on Johnston's reductio of Parfit's position. I contend that although Parfit's own response fails, there are other ways to save the fission argument. The unimportance of identity then comes at a cost, however, because the reductio can only be avoided by accepting either that nothing matters in survival, or else that facts about particles and forces do. Either way, relation R cannot be what matters. (shrink)

The aim of this paper is to show that the A-theorist's argument from experience is undermined by a commitment to ‘experiential punctivism' - the view that instantaneous experiences are metaphysically prior to durative ones. The experiences to which the A-theorist's argument appeals are those of processual events. For these experiences to constitute perceptions of temporal passage it would be necessary to perceive such processes qua processes; but, if experiential punctivism were true, this would be impossible. We could only ever perceive (...) those processes qua temporal variation, which merely amounts to an awareness of change as described by the B-theory. If there is such a phenomenon as the passing of time, it could not be an object of our experience. (shrink)

It is intuitive to suppose that the question of whether I persist through a given period will always have a metaphysically substantive ‘yes’ or ‘no’ answer. Derek Parfit challenges this intuition. Given the truth of Reductionism, he argues, identity can be indeterminate. The main argument Parfit marshals in support of this claim employs his Sorites-style Combined Spectrum thought experiment. Despite its influence, there are conspicuous gaps in his argument. Notably, he claims that identity is indeterminate when questions about persistence are (...) ‘empty’. But indeterminacy in Sorites puzzles is traditionally held to result from vagueness – a topic Parfit avoids. Without an account of the relationships between vagueness, indeterminacy, and question-emptiness, his argument remains incomplete. I begin by outlining Parfit’s argument as it stands. I then propose that we can provide the missing details by supplementing Parfit’s treatment of the Combined Spectrum with Sider’s notion of nonsubstantivity. This gives us a clearer understanding of Parfit’s indeterminacy claim, and affords the room to accommodate vagueness in his argument. Once we spell out what this means, however, it becomes clear that a more radical conclusion is justified by Parfit’s reasoning: it is always an empty question whether a person persists. (shrink)

An abstract framework for structured arguments is presented, which instantiates Dung's ('On the Acceptability of Arguments and its Fundamental Role in Nonmonotonic Reasoning, Logic Programming, and n- Person Games', Artificial Intelligence , 77, 321-357) abstract argumentation frameworks. Arguments are defined as inference trees formed by applying two kinds of inference rules: strict and defeasible rules. This naturally leads to three ways of attacking an argument: attacking a premise, attacking a conclusion and attacking an inference. To resolve such attacks, preferences may (...) be used, which leads to three corresponding kinds of defeat: undermining, rebutting and undercutting defeats. The nature of the inference rules, the structure of the logical language on which they operate and the origin of the preferences are, apart from some basic assumptions, left unspecified. The resulting framework integrates work of Pollock, Vreeswijk and others on the structure of arguments and the nature of defeat and extends it in several respects. Various rationality postulates are proved to be satisfied by the framework, and several existing approaches are proved to be a special case of the framework, including assumption-based argumentation and DefLog. (shrink)

John Pollock (1940?2009) was an influential American philosopher who made important contributions to various fields, including epistemology and cognitive science. In the last 25 years of his life, he also contributed to the computational study of defeasible reasoning and practical cognition in artificial intelligence. He developed one of the first formal systems for argumentation-based inference and he put many issues on the research agenda that are still relevant for the argumentation community today. This paper presents an appreciation of (...) class='Hi'>Pollock's work on defeasible reasoning and its relevance for the computational study of argument. In our opinion, Pollock deserves to be remembered as one of the founding fathers of the field of computational argument, while, moreover, his work contains important lessons for current research in this field, reminding us of the richness of its object of study. (shrink)

Ce texte a déjà paru dans la revue DÉMéter, Université de Lille-3, en juin 2004. Résumé : En interrogeant la notion de rythme – successivement chez Henri Maldiney et chez Paul Valéry – nous montrerons ici qu'une approche chorégraphique de la période dripping du peintre américain Jackson Pollock est possible et qu'elle révèle – au-delà de l'aspect physique de sa peinture – l'état de corps de l'artiste, notion en vogue dans le domaine de la danse, et que nous essaierons (...) à cette occasion de mieux cerner. En - Arts plastiques et autres – GALERIE – Nouvel article. (shrink)

Of all the developments in twentieth century physics, none has given rise to more heated debates than the changes in our understanding of science precipitated by the quantum revolution''. In this revolution, Niels Bohr's dramatically non-classical theory of the atom proved to be the springboard from which the new atomic physics drew it's momentum. Furthermore, Bohr's contribution was crucial not only because his interpretation of quantum mechanics became the most widely accepted view but also because in his role as educator (...) and spokesman for atomic physics Bohr was very much the patron spirit of the entire quantum revolution. The conceptual framework which he proposed to provide a new viewpoint for understanding the quantum theoretical description of atomic systems became for most of this century the dominant outlook of countless productive experimental and theoretical physicists. He called this new framework complementarity''. (shrink)

Princeton University Press, 984. This book is out of print, but can be downloaded as a pdf file (3.9 MB).

The objective of this book is to produce a theory of rational decision making for realistically resource-bounded agents. My interest is not in “What should I do if I were an ideal agent?”, but rather, “What should I do given that I am who I am, with all my actual cognitive limitations?” The book has three parts. Part One addresses the question of where the values come from that agents use in rational decision making. The most comon view among philosophers (...) is that they are based on preferences, but I argue that this is computationally impossible. I propose an alternative theory somewhat reminiscent of Bentham, and explore how human beings actually arrive at values and how they use them in decision making. Part Two investigates the knowledge of probability that is required for decision-theoretic reasoning. I argue that subjective probability makes no sense as applied to realistic agents. I sketch a theory of objective probability to put in its place. Then I use that to define a variety of causal probability and argue that this is the kind of probability presupposed by rational decision making. So what is to be defended is a variety of causal decision theory. Part Three explores how these values and probabilities are to be used in decision making. In chapter eight, it is argued first that actions cannot be evaluated in terms of their expected values as ordinarily defined, because that does not take account of the fact that a cognizer may be unable to perform an action, and may even be unable to try to perform it. An alternative notion of “expected utility” is defined to be used in place of expected values. In chapter nine it is argued that individual actions cannot be the proper objects of decision-theoretic evaluation. We must instead choose plans, and select actions indirectly on the grounds that they are prescribed by the plans we adopt. However, our objective cannot be to find plans with maximal expected utilities. Plans cannot be meaningfully compared in that way. (shrink)

Princeton University Press, 1982. This book is out of print, but can be downloaded as a pdf file (5 MB).

John Pollock aims to construct a theory of rational decision making for real agents--not ideal agents. Pollock argues that theories of ideal rationality are largely irrelevant to the decision making of real agents. Thinking about Acting aims to provide a theory of "real rationality.".

Probability is sometimes regarded as a universal panacea for epistemology. It has been supposed that the rationality of belief is almost entirely a matter of probabilities. Unfortunately, those philosophers who have thought about this most extensively have tended to be probability theorists first, and epistemologists only secondarily. In my estimation, this has tended to make them insensitive to the complexities exhibited by epistemic justification. In this paper I propose to turn the tables. I begin by laying out some rather simple (...) and uncontroversial features of the structure of epistemic justification, and then go on to ask what we can conclude about the connection between epistemology and probability in the light of those features. My conclusion is that probability plays no central role in epistemology. This is not to say that probability plays no role at all. In the course of the investigation, I defend a pair of probabilistic acceptance rules which enable us, under some circumstances, to arrive at justified belief on the basis of high probability. But these rules are of quite limited scope. The effect of there being such rules is merely that probability provides one source for justified belief, on a par with perception, memory, etc. There is no way probability can provide a universal cure for all our epistemological ills. (shrink)

In a number of recent papers I have been developing the theory of "nomic probability," which is supposed to be the kind of probability involved in statistical laws of nature. One of the main principles of this theory is an acceptance rule explicitly designed to handle the lottery paradox. This paper shows that the rule can also handle the paradox of the preface. The solution proceeds in part by pointing out a surprising connection between the paradox of the preface and (...) the gambler's fallacy. (shrink)

This work, edited by Henry Rosemount, Jr, is Volume I in the series of "Critics and Their Critics". Angus C. Graham is the leading translator and interpreter of Chinese philosophical texts; he has written philosophical works of his own, he has written at length and in detail on early Chinese grammar and philology, he has translated Chinese poetry, and he has published some of his own poetry. Graham's polymathic achievement explains the polygenous nature of his collection, which has some (...) essays ranging broadly over aesthetics, ethics, religion, and epistemology; others providing concentrated discussion of specific problems in early Chinese syntax, semantics, etymology, and paleography; and yet others being admixtures, moving by turns through etymology, epistemology, and problems of the translation, interpretation, and dating of Chinese texts. (shrink)

Counterexamples are constructed for the theory of rational choice that results from a direct application of classical decision theory to ordinary actions. These counterexamples turn on the fact that an agent may be unable to perform an action, and may even be unable to try to perform an action. An alternative theory of rational choice is proposed that evaluates actions using a more complex measure, and then it is shown that this is equivalent to applying classical decision theory to "conditional (...) policies" rather than ordinary actions. (shrink)

When your word processor or email program is running on your computer, this creates a “virtual machine” that manipulates windows, files, text, etc. What is this virtual machine, and what are the virtual objects it manipulates? Many standard arguments in the philosophy of mind have exact analogues for virtual machines and virtual objects, but we do not want to draw the wild metaphysical conclusions that have sometimes tempted philosophers in the philosophy of mind. A computer file is not made of (...) epiphenomenal ectoplasm. I argue instead that virtual objects are “supervenient objects.” The stereotypical example of supervenient objects is the statue and the lump of clay. To this end I propose a theory of supervenient objects. Then I turn to persons and mental states. I argue that my mental states are virtual states of a cognitive virtual machine implemented on my body, and a person is a supervenient object supervening on this cognitive virtual machine. (shrink)

A theory of rational choice is a theory of how an agent should, rationally, go about deciding what actions to perform at any given time. For example, I may want to decide whether to go to a movie this evening or stay home and read a book. The actions between which we want to choose are perfectly ordinary actions, and the presumption is that to make such a decision we should attend to the likely consequences of our decision. It is (...) assumed that these decisions must be made in the face of uncertainty regarding both the agent’s initial situation and the consequences of his actions. (shrink)

In a number of recent papers I have been developing the theory of “nomic probability,“ which is supposed to be the kind of probability involved in statistical laws of nature. One of the main principles of this theory is an acceptance rule explicitly designed to handle the lottery paradox. This paper shows that the rule can also handle the paradox of the preface. The solution proceeds in part by pointing out a surprising connection between the paradox of the preface and (...) the gambler's fallacy. (shrink)

David Hume: Moral Philosophy Although David Hume is commonly known for his philosophical skepticism, and empiricist theory of knowledge, he also made many important contributions to moral philosophy. Hume’s ethical thought grapples with questions about the relationship between morality and reason, the role of human emotion in thought and action, the nature of moral … Continue reading David Hume: Moral Philosophy →.

This book is addressed to readers who have laid the foundation of a liberal education & are beginning the special study of law.

Princeton University Press, 1974. This book is out of print, but can be downloaded as a pdf file (5 MB).

In its present incarnation, OSCAR is a fully implemented programmable architecture for a rational agent. If we just focus upon the epistemic reasoning in OSCAR, we have a powerful general-purpose defeasible reasoner. The purpose of this paper is to describe that reasoner. OSCAR's defeasible reasoner is based upon seven fundamental ideas. These are (1) an argument-based account of defeasible reasoning, (2) an analysis of defeat-status given a set of interrelated arguments, (3) a general adequacy criterion for automated defeasible reasoners, called (...) “d.e.-adequacy”, (4) the claim that a generalpurpose defeasible reasoner must have the kind of structure I have called “flag-based”, (5) an algorithm for computing defeat-status, (6) an interest-driven monotonic reasoner, and (7) an account of degrees of justification, degrees of interest, and their interactions. These will each be discussed in turn. (shrink)

The “grand problem” of AI has always been to build artificial agents with human-like intelligence. That is the stuff of science fiction, but it is also the ultimate aspiration of AI. In retrospect, we can understand what a difficult problem this is, so since its inception AI has focused more on small manageable problems, with the hope that progress there will have useful implications for the grand problem. Now there is a resurgence of interest in tackling the grand problem head-on. (...) Perhaps AI has made enough progress on the little problems that we can fruitfully address the big problem. The objective is to build agents of human-level intelligence capable of operating in environments of real-world complexity. I will refer to these as GIAs — “generally intelligent agents”. OSCAR is a cognitive architecture for GIAs, implemented in LISP.1 OSCAR draws heavily on my work in philosophy concerning both epistemology (Pollock 1974, 1986, 1990, 1995, 1998, 2008b, 2008; Pollock and Cruz 1999; Pollock and Oved, 2005) and rational decision making (2005, 2006, 2006a). (shrink)

In this book Pollock deals with the subject of probabilistic reasoning, making general philosophical sense of objective probabilities and exploring their ...

The strategy of this paper is to throw light on rational cognition and epistemic justification by examining irrationality. Epistemic irrationality is possible because we are reflexive cognizers, able to reason about and redirect some aspects of our own cognition. One consequence of this is that one cannot give a theory of epistemic rationality or epistemic justification without simultaneously giving a theory of practical rationality. A further consequence is that practical irrationality can affect our epistemic cognition. I argue that practical irrationality (...) derives from a general difficulty we have in overriding built-in shortcut modules aimed at making cognition more efficient, and all epistemic irrationality can be traced to this same source. A consequence of this account is that a theory of rationality is a descriptive theory, describing contingent features of a cognitive architecture, and it forms the core of a general theory of “voluntary” cognition — those aspects of cognition that are under voluntary control. It also follows that most of the so-called “rules for rationality” that philosophers have proposed are really just rules describing default (non- reflexive) cognition. It can be perfectly rational for a reflexive cognizer to break these rules. The “normativity” of rationality is a reflection of a built-in feature of reflexive cognition — when we detect violations of rationality, we have a tendency to desire to correct them. This is just another part of the descriptive theory of rationality. Although theories of rationality are descriptive, the structure of reflexive cognition gives philosophers, as human cognizers, privileged access to certain aspects of rational cognition. Philosophical theories of rationality are really scientific theories, based on inference to the best explanation, that take contingent introspective data as the evidence to be explained. (shrink)

Pollock describes an exciting theory of rationality and its partial implementation in OSCAR, a computer system whose descendants will literally be persons.

Human beings think of themselves in terms of a privileged non-descriptive designator — a mental “I”. Such thoughts are called “_de se_” thoughts. The mind/body problem is the problem of deciding what kind of thing I am, and it can be regarded as arising from the fact that we think of ourselves non-descriptively. Why do we think of ourselves in this way? We investigate the functional role of “I” (and also “here” and “now”) in cognition, arguing that the use of (...) such non-descriptive “reflexive” designators is essential for making sophisticated cognition work in a general-purpose cognitive agent. If we were to build a robot capable of similar cognitive tasks as humans, it would have to be equipped with such designators. (shrink)

The contributions in this volume make an important effort to resurrect a rather old fashioned form of foundationalism. They defend the position that there are some beliefs that are justified, and are not themselves justified by any further beliefs. This epistemic foundationalism has been the subject of rigorous attack by a wide range of theorists in recent years, leading to the impression that foundationalism is a thing of the past. DePaul argues that it is precisely the volume and virulence of (...) the assaults which points directly to the strength and coherence of the position. (shrink)

This paper is informed by my own participant observation and uses my own ethnography which included conducting in-depth interviews with anonymous paid egg donors and observing a listserv for women considering, pursuing, or having completed egg donation, to illustrate the way that power operates at this particular site of the reproductive center in postmodernity. After outlining who the consumers and providers of eggs are, I will use Foucault's concepts of biopower, disciplinary power, and normativity to describe how anonymous paid egg (...) donation plays a socially useful role in reproducing privilege and in preserving the myth of the nuclear family. Drawing on feminist theorizing to problematize altruism, I will show how the construction of the altruist narrative feeds the preservation of that myth by giving egg donors appropriately feminine motivations. Finally, I will focus on one particular site of resistance on the part of egg donors—controlling their self-presentation, tweaking the pool of eggs—to underscore the simultaneity of control of and control by egg donors. (shrink)

A fellow of Trinity College, Cambridge, and of the Royal Society, William Clifford (1845–79) made his reputation in applied mathematics, but his interests ranged far more widely, encompassing ethics, evolution, metaphysics and philosophy of mind. This posthumously collected two-volume work, first published in 1879, bears witness to the dexterity and eclecticism of this Victorian thinker, whose commitment to the most abstract principles of mathematics and the most concrete details of human experience resulted in vivid and often unexpected arguments. Volume 2 (...) shows Clifford's thorough engagement with scientific thought as a method for illuminating ethical and moral questions. Essays such as 'Body and Mind', 'On the Scientific Basis of Morals' and 'The Ethics of Belief' all variously demonstrate Clifford's core tenet: that beliefs - whether they guide human action or scientific enquiry - 'can never suffer from investigation'. (shrink)

This Hackett edition, first published in 1981, is an unabridged and unaltered republication of the seventh edition as published by Macmillan and Company, Limited. From the forward by John Rawls: In the utilitarian tradition Henry Sidgwick has an important place. His fundamental work, The Methods of Ethics, is the clearest and most accessible formulation of what we may call 'the classical utilitarian doctorine.' This classical doctrine holds that the ultimate moral end of social and individual action is the greatest (...) net sum of the happiness of all sentient beings. Happinesss is specified by the net balance of pleasure over pain, or, as Sidgwick preferred to say, as the net balance of agreeable over disagreeable consciousness.... (shrink)

Internalism in epistemology is the view that all the factors relevant to the justification of a belief are importantly internal to the believer, while externalism is the view that at least some of those factors are external. This extremely modest first approximation cries out for refinement (which we undertake below), but is enough to orient us in the right direction, namely that the debate between internalism and externalism is bound up with the controversy over the correct account of the distinction (...) between justified beliefs and unjustified beliefs.1 Understanding that distinction has occasionally been obscured by attention to the analysis of knowledge and to the Gettier problem, but our view is that these problems, while interesting, should not completely seduce philosophers away from central questions about epistemic justification. A plausible starting point in the discussion of justification is that the distinction between justified beliefs and unjustified beliefs is not the same as the distinction between true beliefs and false beliefs. This follows from the mundane observation that it is possible to rationally believe.. (shrink)