•  305
    Against the no-difference argument
    Analysis. forthcoming.
    There are 1,000 of us and one victim. We each increase the level at which a "discomfort machine" operates on the victim---leading to great discomfort. Suppose that consecutive levels of the machine are so similar that the victim cannot distinguish them. Have we acted permissibly? According to the "no-difference argument" the answer is "yes" because each of our actions was guaranteed to make the victim no worse off. This argument is of interest because if it is sound, similar arguments threa…Read more
  •  466
    I Can’t Believe I’m Stupid
    with Andy Egan
    Philosophical Perspectives 19 (1). 2005.
    It is bad news to find out that one's cognitive or perceptual faculties are defective. Furthermore, it’s not always transparent how one ought to revise one's beliefs in light of such news. Two sorts of news should be distinguished. On the one hand, there is news that a faculty is unreliable -- that it doesn't track the truth particularly well. On the other hand, there is news that a faculty is anti-reliable -- that it tends to go positively wrong. These two sorts of news call for extremely diffe…Read more
  •  1
    Reflection and disagreement
    In Alvin I. Goldman & Dennis Whitcomb (eds.), Social Epistemology: Essential Readings, Oxford University Press. 2011.
  •  1016
    Fragmentation and information access
    In Cristina Borgoni, Dirk Kindermann & Andrea Onofri (eds.), The Fragmented Mind, Oxford University Press. 2021.
    In order to predict and explain behavior, one cannot specify the mental state of an agent merely by saying what information she possesses.  Instead one must specify what information is available to an agent relative to various purposes.  Specifying mental states in this way allows us to accommodate cases of imperfect recall, cognitive accomplishments involved in logical deduction, the mental states of confused or fragmented subjects, and the difference between propositional knowledge and know-ho…Read more
  •  487
    Confession of a causal decision theorist
    Analysis 82 (2): 203-213. 2022.
    (1) Suppose that you care only about speaking the truth, and are confident that some particular deterministic theory is true. If someone asks you whether that theory is true, are you rationally required to answer "yes"? (2) Suppose that you face a problem in which (as in Newcomb's problem) one of your options---call it "taking two boxes"---causally dominates your only other option. Are you rationally required to take two boxes? Those of us attracted to causal decision theory are under pressure…Read more
  •  1154
    Fragmentation and logical omniscience
    with Agustín Rayo
    Noûs 56 (3): 716-741. 2022.
    It would be good to have a Bayesian decision theory that assesses our decisions and thinking according to everyday standards of rationality — standards that do not require logical omniscience (Garber 1983, Hacking 1967). To that end we develop a “fragmented” decision theory in which a single state of mind is represented by a family of credence functions, each associated with a distinct choice condition (Lewis 1982, Stalnaker 1984). The theory imposes a local coherence assumption guaranteeing tha…Read more
  •  499
    Infinitesimal chances and the laws of nature
    Australasian Journal of Philosophy 82 (1). 2004.
    The 'best-system' analysis of lawhood [Lewis 1994] faces the 'zero-fit problem': that many systems of laws say that the chance of history going actually as it goes--the degree to which the theory 'fits' the actual course of history--is zero. Neither an appeal to infinitesimal probabilities nor a patch using standard measure theory avoids the difficulty. But there is a way to avoid it: replace the notion of 'fit' with the notion of a world being typical with respect to a theory.
  •  246
    Newcomb University: A play in one act
    Analysis 80 (2): 212-221. 2020.
    Counter-intuitive consequences of both causal decision theory and evidential decision theory are dramatized. Each of those theories is thereby put under some pressure to supply an error theory to explain away intuitions that seem to favour the other. Because trouble is stirred up for both sides, complacency about Newcomb’s problem is discouraged.
  •  108
    The ability to analyze arguments is critical for higher-level reasoning, yet previous research suggests that standard university education provides at best modest improvements in students’ analytical reasoning abilities. What techniques are most effective for cultivating these skills? Here we investigate the effectiveness of a 12-week undergraduate seminar in which students practice a software-based technique for visualizing the logical structures implicit in argumen- tative texts. Seminar stude…Read more
  •  23
    Poza niepewnością co do tego, jaki jest świat, można być także niepewnym swojego przestrzennego lub czasowgo położenia w świecie. Celem artykułu jest postawienie problemu wynikającego z połączenia tych dwóch rodzajów niepewności, a następnie rozwiązanie go i wyciągnięcie dwóch lekcji z tego rozwiązania.
  •  398
    Statistical Mechanics and the Asymmetry of Counterfactual Dependence
    Philosophy of Science 68 (3): 313-324. 2000.
    In "Counterfactual Dependence and Time's Arrow", David Lewis defends an analysis of counterfactuals intended to yield the asymmetry of counterfactual dependence: that later affairs depend counterfactually on earlier ones, and not the other way around. I argue that careful attention to the dynamical properties of thermodynamically irreversible processes shows that in many ordinary cases, Lewis's analysis fails to yield this asymmetry. Furthermore, the analysis fails in an instructive way: it teac…Read more
  • Counterfactuals, Dispositions, and Conscious Experience: Essays on Entropy
    Dissertation, Massachusetts Institute of Technology. 2001.
    Chapter 1 of this thesis concerns counterfactual conditionals. David Lewis has offered a natural and influential analysis of counterfactuals. But the analysis fails to take into account the asymmetry of entropy, and comes to grief precisely because of that failure. The cause of the grief is that processes involving the increase of entropy are exceedingly sensitive to small changes in their final conditions. ;Chapter 2 concerns robust dispositions. Drop an ordinary rock into hydrofluoric acid, an…Read more
  •  226
    On overrating oneself... And knowing it
    Philosophical Studies 123 (1-2): 115-124. 2005.
    When it comes to evaluating our own abilities and prospects, most people are subject to a distorting bias. We think that we are better – friendlier, more well-liked, better leaders, and better drivers – than we really are. Once we learn about this bias, we should ratchet down our self-evaluations to correct for it. But we don’t. That leaves us with an uncomfortable tension in our beliefs: we knowingly allow our beliefs to differ from the ones that we think are supported by our evidence. We can m…Read more
  •  418
    The puzzle of the unmarked clock and the new rational reflection principle
    Philosophical Studies 164 (1): 127-139. 2013.
    The “puzzle of the unmarked clock” derives from a conflict between the following: (1) a plausible principle of epistemic modesty, and (2) “Rational Reflection”, a principle saying how one’s beliefs about what it is rational to believe constrain the rest of one’s beliefs. An independently motivated improvement to Rational Reflection preserves its spirit while resolving the conflict
  •  703
    How to Disagree about How to Disagree
    In Richard Feldman & Ted A. Warfield (eds.), Disagreement, Oxford University Press. pp. 175-186. 2010.
    When one encounters disagreement about the truth of a factual claim from a trusted advisor who has access to all of one's evidence, should that move one in the direction of the advisor's view? Conciliatory views on disagreement say "yes, at least a little." Such views are extremely natural, but they can give incoherent advice when the issue under dispute is disagreement itself. So conciliatory views stand refuted. But despite first appearances, this makes no trouble for *partly* conciliatory vie…Read more
  •  1240
    Reflection and disagreement
    Noûs 41 (3). 2007.
    How should you take into account the opinions of an advisor? When you completely defer to the advisor's judgment, then you should treat the advisor as a guru. Roughly, that means you should believe what you expect she would believe, if supplied with your extra evidence. When the advisor is your own future self, the resulting principle amounts to a version of the Reflection Principle---a version amended to handle cases of information loss. When you count an advisor as an epistemic peer, you shoul…Read more
  •  51
    Head direction (HD) cells, abundant in the rat postsubiculum and anterior thalamic nuclei, fire maximally when the rat’s head is facing a particular direction. The activity of a population of these cells forms a distributed representation of the animal’s current heading. We describe a neural network model that creates a stable, distributed representation of head direction and updates that representation in response to angular velocity information. In contrast to earlier models, our model of the h…Read more
  •  185
    Isolation and folk physics
    In Huw Price & Richard Corry (eds.), Causation, Physics, and the Constitution of Reality: Russell's Republic Revisited, Oxford University Press. 2005.
    There is a huge chasm between the notion of lawful determination that figures in fundamental physics, and the notion of causal determination that figures in the "folk physics" of everyday objects. In everyday life, we think of the behavior of an ordinary object as being determined by a small set of simple conditions. But in fundamental physics, no such conditions suffice to determine an ordinary object's behavior. What bridges the chasm is that fundamental physical laws make the folk picture of …Read more
  •  730
    In addition to being uncertain about what the world is like, one can also be uncertain about one’s own spatial or temporal location in the world. My aim is to pose a problem arising from the interaction between these two sorts of uncertainty, solve the problem, and draw two lessons from the solution.
  •  126
    Bayesian humility
    Philosophy of Science 83 (3): 305-323. 2016.
    Say that an agent is "epistemically humble" if she is less than certain that her opinions will converge to the truth, given an appropriate stream of evidence. Is such humility rationally permissible? According to the orgulity argument : the answer is "yes" but long-run convergence-to-the-truth theorems force Bayesians to answer "no." That argument has no force against Bayesians who reject countable additivity as a requirement of rationality. Such Bayesians are free to count even extreme humility…Read more
  •  411
    Fred comes to realize that if his parents had settled in a more conservative neighborhood, he would have—on the basis of essentially the same evidence—arrived at political views quite different from his actual views. Furthermore, his parents chose between liberal and conservative neighborhoods by tossing a coin. (Sher 2001)
  •  368
    Subjective Probabilities Should be Sharp
    Philosophers' Imprint 10. 2010.
    Many have claimed that unspecific evidence sometimes demands unsharp, indeterminate, imprecise, vague, or interval-valued probabilities. Against this, a variant of the diachronic Dutch Book argument shows that perfectly rational agents always have perfectly sharp probabilities.
  •  304
    Defeating dr. evil with self-locating belief
    Philosophy and Phenomenological Research 69 (2). 2004.
    Dr. Evil learns that a duplicate of Dr. Evil has been created. Upon learning this, how seriously should he take the hypothesis that he himself is that duplicate? I answer: very seriously. I defend a principle of indifference for self-locating belief which entails that after Dr. Evil learns that a duplicate has been created, he ought to have exactly the same degree of belief that he is Dr. Evil as that he is the duplicate. More generally, the principle shows that there is a sharp distinction betw…Read more