Robert Nozick, in chapter two of the nature of rationality, proposes two famous problems in decision theory (i.e., Newcomb's problem and Prisoner Dilemma) and two main strategies toward these problems i.e. dominant strategy and dominated or cooperative one. He will try to give a formal principles to calculate the decision values in these situations. In this calculation he goes beyond the standard principle of maximizing expected utility and would try to put forth less ideal and more realistic principles that fit (...) the decision situation in the real world. (shrink)

Some philosophers worry that if modal realism is true, you have no reason to prevent evils. For if you prevent an evil, you’ll have a counterpart somewhere that allows a similar evil. And if you refrain, your counterpart will end up preventing the relevant evil. Either way one evil is prevented and one is allowed. Your act makes no difference. I argue that this is mistaken. If modal realism is true, you are in a variant of Newcomb’s Problem. And if (...) Lewis’ view about Newcomb’s Problem is true, then your act does make a difference and you should prevent the evil. (shrink)

Standard game theory cannot explain the selection of payoff-dominant outcomes that are best for all players in common-interest games. Theories of team reasoning can explain why such mutualistic cooperation is rational. They propose that teams can be agents and that individuals in teams can adopt a distinctive mode of reasoning that enables them to do their part in achieving Pareto-dominant outcomes. We show that it can be rational to play payoff-dominant outcomes, given that an agent group identifies. We compare team (...) reasoning to other theories that have been proposed to explain how people can achieve payoff-dominant outcomes, especially with respect to rationality. Some authors have hoped that it would be possible to develop an argument that it is rational to group identify. We identify some large—probably insuperable—problems with this project and sketch some more promising approaches, whereby the normativity of group identification rests on morality. (shrink)

In Bermúdez 2013 I argued against David Lewis’s well-known and widely accepted claim that Newcomb’s problem and the prisoner’s dilemma are really notational variants of a single problem. Mark Walker’s paper in this journal takes issue with my argument. In this note I show how Walker’s criticisms are misplaced. The problems with Walker’s argument point to more general and independently interesting conclusions about, first, the relation between deliberation and decision and, second, the differences between the prisoner’s dilemma, which is a (...) strategic choice problem, and Newcomb’s problem, which is a parametric choice problem. (shrink)

Causal decision theory (CDT) cares only about the effects of a contemplated act, not its causes. The article constructs a case in which CDT consequently recommends a bet that the agent is certain to lose, rather than a bet that she is certain to win. CDT is plainly giving wrong advice in this case. It therefore stands refuted. 1 The Argument2 The Argument in More Detail2.1 The betting mechanism2.2 Soft determinism2.3 The content of P 2.4 The argument again3 The Descriptive (...) Premise3.1 Causal decision theory3.2 Causal decision theory prefers A14 The Normative Premise5 Objections5.1 Table 1 and Table 2 are misleading5.2 The agency theory of causation5.3 The payment mechanism5.4 Newcomb’s problem5.5 Against the normative premise5.6 Drop soft determinism. (shrink)

In “A Subjectivist’s Guide to Objective Chance,” David Lewis says that he is “led to wonder whether anyone but a subjectivist is in a position to understand objective chance.” The present essay aims to motivate this same Lewisean attitude, and a similar degree of modest subjectivism, with respect to objective causation. The essay begins with Newcomb problems, which turn on an apparent tension between two principles of choice: roughly, a principle sensitive to the causal features of the relevant situation, and (...) a principle sensitive only to evidential factors. Two-boxers give priority to causal beliefs, and one-boxers to evidential beliefs. The essay notes that a similar issue can arise when the modality in question is chance, rather than causation. In this case, the conflict is between decision rules based on credences guided solely by chances, and rules based on credences guided by other sorts of probabilistic evidence. Far from excluding cases of the latter kind, Lewis’s Principal Principle explicitly allows for them, in the form of the caveat that credences should follow beliefs about chances only in the absence of “inadmissible evidence.” The essay then exhibits a tension in Lewis’s views on these two matters, by presenting a class of decision problems—some of them themselves Newcomb problems—in which Lewis’s view of the relevance of inadmissible evidence seems in tension with his causal decision theory. It offers a diagnosis for this dilemma and proposes a remedy, based on an extension of a proposal due to Ned Hall and others from the case of chance to that of causation. The remedy suggests a new view of the relation between causal decision theory and evidential decision theory, namely, that they stand to each other much as chance stands to credence, being objective and subjective faces of the same practical coin. This has much the same metaphysical benefits as Lewis’s own view of chance and also throws interesting new light on Newcomb problems, providing an irenic resolution of the apparent disagreement between causal and evidential decision rules. (shrink)

Abstract In an engaging and ingenious paper, Irvine (1993) purports to show how the resolution of Braess? paradox can be applied to Newcomb's problem. To accomplish this end, Irvine forges three links. First, he couples Braess? paradox to the Cohen?Kelly queuing paradox. Second, he couples the Cohen?Kelly queuing paradox to the Prisoner's Dilemma (PD). Third, in accord with received literature, he couples the PD to Newcomb's problem itself. Claiming that the linked models are ?structurally identical?, he argues that Braess solves (...) Newcomb's problem. This paper shows that Irvine's linkage depends on structural similarities?rather than identities?between and among the models. The elucidation of functional disanalogies illuminates structural dissimilarities which sever that linkage. I claim that the Cohen?Kelly queuing paradox cloaks a fine structure that decouples it from both Braess? paradox and the PD (Marinoff, 1996a). I further assert that the putative reduction of the PD to a Newcomb problem (e.g. Brams, 1975; Lewis, 1979) is seriously flawed. It follows that Braess? paradox does not solve Newcomb's problem via the foregoing and herein sundered chain. I conclude by substantiating a stronger claim, namely that Braess'paradox cannot solve Newcomb's problem at all. (shrink)

Self-reference in semantics, which leads to well-known paradoxes, is a thoroughly researched subject. The phenomenon can appear also in decision theoretic situations. There is a structural analogy between the two and, more interestingly, an analogy between principles concerning truth and those concerning rationality. The former can serve as a guide for clarifying the latter. Both the analogies and the disanalogies are illuminating.

Proponents of causal decision theories argue that classical Bayesian decision theory (BDT) gives the wrong advice in certain types of cases, of which the clearest and commonest are the medical Newcomb problems. I defend BDT, invoking a familiar principle of statistical inference to show that in such cases a free agent cannot take the contemplated action to be probabilistically relevant to its causes (so that BDT gives the right answer). I argue that my defence does better than those of Ellery (...) Eells and Richard Jeffrey; and that it applies, where necessary, to other types of Newcomb problem. (shrink)

Among various cases that equally admit of evidentialist reasoning, the supposedly evidentialist solution has varying degrees of intuitive attractiveness. I suggest that cooperative reasoning may account for the appeal of apparently evidentialist behavior in the cases in which it is intuitively attractive, while the inapplicability of cooperative reasoning may account for the unattractiveness of evidentialist behaviour in other cases. A collective causal power with respect to agreed outcomes, not evidentialist reasoning, makes cooperation attractive in the Prisoners' Dilemma. And a natural (...) though unwarranted assumption of such a power may account for the intuitive appeal of the one-box response in Newcomb's Problem. (shrink)

I present a game-theoretic way to understand the situation describing Newcomb’s Problem (NP) which helps to explain the intuition of both one-boxers and two-boxers. David Lewis has shown that the NP may be modelled as a Prisoners Dilemma game (PD) in which ‘cooperating’ corresponds to ‘taking one box’. Adopting relevant results from game theory, this means that one should take just one box if the NP is repeated an indefinite number of times, but both boxes if it is a one-shot (...) game. Causal decision theorists thus give the right answer for the one-shot situation, whereas the one-boxers’ solution applies to the indefinitely iterated case. Because Nozick’s set-up of the NP is ambiguous between a one-shot and a repeated game, both of these solutions may appear plausible – depending on whether one conceives of the situation as one-off or repeated. If the players’ aim is to maximize their payoffs, the symmetric structure of the PD implies that the two players will behave alike both when the game is one-shot and when it is played repeatedly. Therefore neither the observed outcome of both players selecting the same strategy (in the PD) nor, correspondingly, the predictor’s accurate prediction of this outcome (in the NP) is at all surprising. There is no need for a supernatural predictor to explain the NP phenomena. (shrink)

Philosophers’ two favorite accounts of rational choice, Evidential Decision Theory (EDT) and Causal Decision Theory (CDT), each face a number of serious objections. Especially troubling are the recent charges that these theories are dynamically inconsistent. I note here that, under the epistemic assumptions that validate these charges, every decision theory that satisfies a pair of attractive postulates is doomed to a similar fate and then survey various lessons rational choice theorists might opt to draw from this.

David Lewis argued that Newcomb’s Problem and the Prisoner’s Dilemma are “one and the same problem” or, to be more precise, that the Prisoner’s Dilemma is nothing else than “two Newcomb problems side by side” (Lewis Philosophy and Public Affairs 8:235–240, 1979 : 235). It has been objected that his argument fails to take into account certain epistemic asymmetries which undermine the one-problem thesis. Sobel ( 1985 ) acknowledges that many tokens satisfy the structural requirements of both problems, while questioning (...) the generality of the thesis. Bermúdez (Analysis 73:423–429, 2013 ), on the other hand, argues that there is a deeper structural conflict between the two problems in the sense that the epistemic requirements that give Newcomb’s Problem its force are precisely those that prevent it from being a Prisoner’s Dilemma. I argue that the epistemic asymmetry objections raised by Sobel and Bermúdez fail to undermine the one-problem thesis. A different type of objection raised by Bermúdez, one which relies on the contrast between parametric and strategic choices, fares no better. Although NP is a problem that has been primarily studied for its implications to decision theory, it contains enough game theoretic elements to justify the claim that a juxtaposition of two such problems can be thought of as a strategic game. (shrink)

In Nozick’s rendition of the decision situation given in Newcomb’s Paradox dominance and the principle of maximum expected utility recommend different strategies. While evidential decision theory seems to be split over which principle to apply and how to interpret the principles in the first place, causal decision theory seems to go for the solution recommended by dominance. As a reply to the CDT proposal by Wolfgang Spohn, who opts for “one-boxing” by employing reflexive decision graphs, I will draw on the (...) framework of causal knowledge patterns, i.e., Bayes net causal models, augmented by non-causal knowledge, to finally arrive at “one-boxing” – more intuitively and more closely to what actually is in Nozick’s story. This proposal allows the careful re-examination of all relevant concepts in the original story and might cast new light on the following questions: How may causality in general be understood to allow causal inference from hybrid patterns encoding subjective knowledge? How can the notion of prediction be analyzed – philosophically and formally? And what’s the decision-maker’s conceptualization of the situation he will act upon? (shrink)

This item has been retired at the request of its author.

The concepts of omniscience and omnipotence are defined in 2 ? 2 ordinal games, and implications for the optimal play of these games, when one player is omniscient or omnipotent and the other player is aware of his omniscience or omnipotence, are derived. Intuitively, omniscience allows a player to predict the strategy choice of an opponent in advance of play, and omnipotence allows a player, after initial strategy choices are made, to continue to move after the other player is forced (...) to stop. Omniscience and its awareness by an opponent may hurt both players, but this problem can always be rectified if the other player is omniscient. This pathology can also be rectified if at least one of the two players is omnipotent, which can override the effects of omniscience. In some games, one player's omnipotence ? versus the other's ? helps him, whereas in other games the outcome induced does not depend on which player is omnipotent. Deducing whether a player is superior (omniscient or omnipotent) from the nature of his game playing alone raises several problems, however, suggesting the difficulty of devising tests for detecting superior ability in games. (shrink)

Many philosophers (myself included) have been converted to causal decision theory by something like the following line of argument: Evidential decision theory endorses irrational courses of action in a range of examples, and endorses “an irrational policy of managing the news”. These are fatal problems for evidential decision theory. Causal decision theory delivers the right results in the troublesome examples, and does not endorse this kind of irrational news-managing. So we should give up evidential decision theory, and be causal decision (...) theorists instead. Unfortunately, causal decision theory has its own family of problematic examples for which it endorses irrational courses of action, and its own irrational policy that it is committed to endorsing. These are, I think, fatal problems for causal decision theory. I wish that I had another theory to offer in its place. (shrink)

A fully adequate solution to Newcomb’s Problem (Nozick 1969) should reveal the source of its extraordinary elusiveness and persistent intractability. Recently, a few accounts have independently sought to meet this criterion of adequacy by exposing the underlying source of the problem’s profound puzzlement. Thus, Sorensen (1987), Slezak (1998), Priest (2002) and Maitzen and Wilson (2003) share the ‘no box’ view according to which the very idea that there is a right choice is misconceived since the problem is ill-formed or incoherent (...) in some way. Among proponents of this view, Richard Jeffrey (2004) recently declared that he renounces his earlier position that accepted Newcomb problems as genuine decision problems. Significantly, Jeffrey suggests that “Newcomb problems are like Escher’s famous staircase on which an unbroken ascent takes you back where you started” (Jeffrey (2004; 113)). Jeffrey’s analogy is apt for a puzzle whose specific logical features can be precisely articulated. Along the lines of these related approaches, I propose to improve and clarify them by providing such a deeper analysis that elucidates their essential, related insights. (shrink)

It is commonly thought, in line with the position defended in an influential paper by David Lewis, that the decision problems faced in the prisoner’s dilemma and the Newcomb situation are essentially the same problem. José Luis Bermúdez has recently attacked the case Lewis makes for this claim. While I think the claim is false, I contend that Bermúdez’s reason for rejecting Lewis’s argument is inadequate, and then outline what I take to be a better reason for doing so.

‘Ifs’ come washed or unwashed. The washed ifs are embedded in precise theories: the constantly strict implication of deductive inference, the variably strict implication of ‘nearness’ conditionals, and statements of conditional probability. By a nearness conditional I mean the common part of Stalnaker's and D. Lewis's theory of counterfactual conditionals, which depends on a notion that possible worlds are more or less near to each other, as a measure of their over-all similarity to each other.

I have maintained that some but not all prisoners' dilemmas are side-by-side Necomb problems. The present paper argues that, similarly, some but not all versions of Newcomb's Problem are prisoners' dilemmas in which Taking Two and Predicting Two make an equilibrium that is dispreferred by both the box-chooser and predictor to the outcome in which only one box is taken and this is predicted. I comment on what kinds of prisoner's dilemmas Newcomb's Problem can be, and on opportunities that results (...) reached may open for kinds of cooperative reasoning in versions of Newcomb's Problem. (shrink)

Should we act only for the sake of what we might bring about (causal decision theory); or is it enough for a decent motive that our action is highly correlated with something desirable (evidential decision theory)? The conflict between these points of view is embodied in Newcomb's problem. It is argued here that intuitive evidence from familiar decision contexts does not enable us to settle the issue, since the two theories dictate the same results in normal circumstances. Nevertheless, there are (...) several reasons to reject the causal approach: (1) its relative complexity; (2) its commitment to the existence of situations in which every possible act would be irrational; (3) its incorporation of an arbitrary time bias; and (4) its implicit distinction between what ought to be done and what ought to be hoped for. (shrink)

This article presents a rule-utilitarian theory which lies much closer to the social contract tradition than most other forms of consequentialism do: calculated-rates rule preference utilitarianism. Being preference-utilitarian allows the theory to be grounded in instrumental rationality and the equality of agents, as opposed to teleological assumptions about impartial goodness. The calculated-rates approach, judging rules’ consequences by what would happen if they were accepted by whatever number of people is realistic rather than by what would happen if they were accepted (...) universally or by exactly 90% of the population, allows it to select rules based not just on their ability to give good advice to their followers but also on their ability to attract followers in the first place. The result is a theory that, although fully utilitarian and not at all pluralistic or intuitionist, nevertheless offers a principled justification for giving some weight to seemingly non-utilitarian considerations: Lockean natural rights, Kantian respect for autonomy, and Scanlonian distributive justice. (shrink)

David Gauthier in his article, Maximization constrained: the rationality of cooperation, tries to defend of the joint strategy in situations which no outcome is both equilibrium and optimal. Prisoner’s Dilemma is the most familiar example of these situations. He first starts with some quotes by Hobbes in Leviathan; Hobbes, in chapter 15 discusses an objection by someone is called Foole, and then will reject his view. In response to Foole, Hobbes presents two strategies (i.e. joint and individual) and two kinds (...) of agents in such problems including Prisoner’s Dilemma – i.e. straightforward maximizer (SM) and constrained maximizer(CM). Then he considers two arguments respectively for SM and CM, and he will show that why in an ideal and transparent situation, the first argument fails and the second one would be the only valid argument. likewise, in the following part of his article, he considers more realistic situations with translucency and he concludes that under some conditions, joint strategy would be still the rational decision. (shrink)

ABSTRACT In social evolution theory, biological individuals are often represented on the model of rational agents, that is, as if they were ‘seeking’ to maximize their own reproductive success. In the 1990s, important criticisms of this mode of thinking were made by Brian Skyrms and Elliott Sober, who both argued that ‘rational agent’ models can lead to incorrect predictions when there are positive correlations between individuals’ phenotypes. In this article, I argue that one model of rational choice—namely, Savage’s model —can (...) actually be vindicated in evolutionary biology, provided that the pay-offs are computed in inclusive fitness terms. I also show that the use of this model is better avoided when pay-offs are non-additive, or when certain causal influences affect the outcome of natural selection. The result is a partial rehabilitation of this mode of thinking, conditional on both the additivity of the pay-off structure and the absence of any form of manipulation or coercion. _1_ Introduction _2_ When Natural Selection and Rational Deliberation Part Ways _3_ A Simple Solution: Redefining the Pay-offs in Inclusive Fitness Terms _4_ Sober on Inclusive Fitness Maximization _5_ Inclusive Fitness with Non-additive Pay-offs _6_ Causal Influences and the Savage– Hamilton Model _6.1_ Reciprocity and partner choice _6.2_ Coercion and manipulation _7_ Conclusion Appendix. (shrink)

According to David Lewis, the prisoner's dilemma (PD) and Newcomb's problem (NP) are really just one dilemma in two different forms (Lewis 1979). Lewis's argument for this conclusion is ingenious and has been widely accepted. However, it is flawed. As this paper shows, the considerations that Lewis brings to bear to show that the game he starts with is an NP equally show that the game is not a PD.

According to some views of reality, some objects are fundamental and other objects depend for their existence upon these fundamental objects. In this article, I argue that we have reason to reject these views.

Abstract Newcomb's problem is regularly described as a problem arising from equally defensible yet contradictory models of rationality. Braess? paradox is regularly described as nothing more than the existence of non?intuitive (but ultimately non?contradictory) equilibrium points within physical networks of various kinds. Yet it can be shown that Newcomb's problem is structurally identical to Braess? paradox. Both are instances of a well?known result in game theory, namely that equilibria of non?cooperative games are generally Pareto?inefficient. Newcomb's problem is simply a limiting (...) case in which the number of players equals one. Braess? paradox is another limiting case in which the ?players? need not be assumed to be discrete individuals. The result is that Newcomb's problem is no more difficult to solve than (the easy to solve) Braess? paradox. (shrink)

The proper treatment of correlation in evolutionary game theory has unexpected connections with recent philosophical discussions of the theory of rational decision. The Logic of Decision (Jeffrey 1983) provides the correct framework for correlated evolutionary game theory and a variant of "ratifiability" is the appropriate generalization of "evolutionarily stable strategy". The resulting theory unifies the treatment of correlation due to kin, population viscosity, detection, signaling, reciprocal altruism, and behavior-dependent contexts. It is shown that (1) a strictly dominated strategy may be (...) selected, and (2) under conditions of perfect correlation a strictly efficient strategy must be selected. (shrink)

Newcomb’s problem involves a decision-maker faced with a choice and a predictor forecasting this choice. The agents’ interaction seems to generate a choice dilemma once the decision-maker seeks to apply two basic principles of rational choice theory : maximize expected utility ; adopt the dominant strategy. We review unsuccessful attempts at pacifying the dilemma by excluding Newcomb’s problem as an RCT-application, by restricting MEU and ADS, and by allowing for backward causation. A probability approach shows that Newcomb’s original problem-formulation lacks (...) causal information. This makes it impossible to specify the probability structure of Newcomb’s univocally. Once missing information is added, Newcomb’s problem and RCT re-align, thus explaining Newcomb’s problem as a seeming dilemma. Building on Wolpert and Benford :1637–1646, 2013), we supply additional details and offer a crucial correction to their formal proof. (shrink)

‘Ifs’ come washed or unwashed. The washed ifs are embedded in precise theories: the constantly strict implication of deductive inference, the variably strict implication of ‘nearness’ conditionals, and statements of conditional probability. By a nearness conditional I mean the common part of Stalnaker's and D. Lewis's theory of counterfactual conditionals, which depends on a notion that possible worlds are more or less near to each other, as a measure of their over-all similarity to each other.

The more you think about it, the more baffling Newcomb's Problem becomes. To most people, at first it is obvious which solution is correct, but their confidence can be eroded easily. Only a puzzled few are torn between the two right from the start, and for years so was I. But at last, thanks to a certain metaargument, one solution came to seem obvious to me. And yet, imagining myself actually faced with Newcomb's choice, I started to worry that I (...) might experience just enough last-minute ambivalence to unsettle my confidence in that argument. Fortunately, I have found a strategy to ensure making the right choice when the chips are down.Not only is Newcomb's Problem puzzling in its own right, it is philosophically significant. The appeal of both solutions reflects a conflict between two plausible conceptions of rational choice. In making a decision, should one consider all of its probabilistic consequences or only its causal consequences? Each conception has its supporters, but some philosophers find them both defensible and see no hope of resolving the conflict. I think the conflict can be resolved, at least in the context of Newcomb's Problem, by properly assessing the relevant counterfactual conditionals. (shrink)

The paper’s target is the historically influential betting interpretation of subjective probabilities due to Ramsey and de Finetti. While there are several classical and well-known objections to this interpretation, the paper focuses on just one fundamental problem: There is a sense in which degrees of belief cannot be interpreted as betting rates. The reasons differ in different cases, but there’s one crucial feature that all these cases have in common: The agent’s degree of belief in a proposition A does not (...) coincide with her degree of belief in a conditional that A would be the case if she were to bet on A, where the belief in this conditional itself is conditioned on the supposition that the agent will have an opportunity to make such a bet. Even though the two degrees of belief sometimes can coincide (they will coincide in those cases when the bet has no expected causal bearings on the proposition A and the opportunity to bet have no evidential bearings on that proposition), it is the latter belief rather than the former that guides the agent’s rational betting behaviour. The reason is that this latter belief takes into consideration potential interferences that bet opportunities and betting itself might create with regard to the proposition to be betted on. It is because of this interference problem that the agent’s degree of belief in A cannot be interpreted as her betting rate for A. (shrink)

This article is about the analogy between inclusive fitness and utility. In behavioral ecology, it is often assumed that individual organisms behave as if they were “striving” to maximize their inclusive fitness—a measure analogue to the kind of utility function that is used to represent the preferences of rational agents. Here, I explore some conceptual puzzles related to this view and question whether the kind of biological utility posited by the advocates of the “maximizing agent analogy” can be adequately interpreted (...) in inclusive fitness terms. (shrink)

You should rather play hide-and-seek against someone who cannot predict where you hide than against someone who can, as the article illustrates in connection with a high-stakes example. Causal Decision Theory denies this. So Causal Decision Theory is false.

This paper aims to make three contributions to decision theory. First there is the hope that it will help to re-establish the legitimacy of the problem, pace various recent analyses provided by Maitzen and Wilson, Slezak and Priest. Second, after pointing out that analyses of the problem have generally relied upon evidence that is conditional on the taking of one particular option, this paper argues that certain assumptions implicit in those analyses are subtly flawed. As a third contribution, the piece (...) aims to draw attention to an important similarity between Newcomb’s problem and the toxin puzzle. In short, both problems illustrate the fact that you can have a reason to intend to φ without having a reason to actually φ. (shrink)

Payoff dominance, a criterion for choosing between equilibrium points in games, is intuitively compelling, especially in matching games and other games of common interests, but it has not been justified from standard game-theoretic rationality assumptions. A psychological explanation of it is offered in terms of a form of reasoning that we call the Stackelberg heuristic in which players assume that their strategic thinking will be anticipated by their co-player(s). Two-person games are called Stackelberg-soluble if the players' strategies that maximize against (...) their co-players' best replies intersect in a Nash equilibrium. Proofs are given that every game of common interests is Stackelberg-soluble, that a Stackelberg solution is always a payoff-dominant outcome, and that in every game with multiple Nash equilibria a Stackelberg solution is a payoff-dominant equilibrium point. It is argued that the Stackelberg heuristic may be justified by evidentialist reasoning. (shrink)

Richard Jeffrey said that Newcomb’s Problem may be seen “as a rock on which... Bayesianism... must founder” and the problem has been almost universally conceived as reconciling the science-fictional features of the decision problem with a plausible causal analysis. Later, Jeffrey renounced his earlier position that accepted Newcomb problems as genuine decision problems, suggesting “Newcomb problems are like Escher’s famous staircase”. We may interpret this to mean that we know there can be no such thing, though we see no local (...) flaw in the puzzle. In this paper, I develop the critique of Slezak to show that Jeffrey’s analogy is apt for a puzzle whose logical features can be precisely articulated and I propose an easily realizable experiment that convincingly supports this analysis. I suggest that these real-life analogs of Newcomb’s Problem have diverted attention from the essential function of the science-fiction of a predicting demon. Following Eells, similarities with realistic problems such as Prisoner’s Dilemma and common cause cases have suggested that Newcomb’s Problem may be given a coherent description and realized in some way consistent with classical causation. However, the peculiarity of the apparent link between one’s choice and the previously determined contents of the second box is the central, defining feature of Newcomb’s Problem. I argue that the predictor may not be merely a fiction providing insufficient “extra information” as both McKay and Levi suggest. Rather, I suggest that the decision problem permits a precise specification revealing the source of the notorious perplexity. Notwithstanding efforts to rescue the coherence of Newcomb’s Problem and a classical causal account, a simulation of the decision problem establishes the correctness of my analysis and, thereby, hopefully ending the debate. (shrink)

Against the contention of David Lewis Philosophy and Public Affairs 8, 235–240, that the Prisoner’s Dilemma is a Newcomb Problem, José Luis Bermúdez Analysis 73, 423–429, has urged that Lewis’s assimilation removes the very outcome scenarios that make the Dilemma so puzzling. I objected that this criticism of Lewis presupposes that the Dilemma is harder to resolve than Newcomb’s Problem, in effect challenging Bermúdez to justify this assumption. In his 2015 he takes up the challenge, arguing that while the former (...) presents a problem of strategic choice the latter is problem of parametric choice. I argue here that appeal to the distinction between these two kinds of choice cannot sustain the rejection of Lewis’s view. (shrink)