Shuford, Albert and Massengill proved, a half century ago, that the logarithmic scoring rule is the only proper measure of inaccuracy determined by a differentiable function of probability assigned the actual cell of a scored partition. In spite of this, the log rule has gained less traction in applied disciplines and among formal epistemologists that one might expect. In this paper we show that the differentiability criterion in the Shuford et. al. result is unnecessary and use the resulting simplified characterization (...) of the logarithmic rule to give novel arguments in favor of it. (shrink)

Schoenfield has constructed examples of proper inaccuracy measures that value verisimilitude (in a certain sense) in spaces of worlds equipped with a particular variety of verisimilitude metric. However, Schoenfield left it as an open question whether ‘for every space of worlds, there is a proper inaccuracy measure that values verisimilitude’. Here I answer this question in the affirmative.

Adams' Thesis states that the probability of a conditional is the probability of the consequent conditional on the antecedent. S. Kaufmann introduced a rival method, the so-called ``local interpretation'', for calculating the probability of a conditional that, according to a purported majority, squares better with intuition in some circumstances. He also gives an example purporting to show that this new method sometimes corresponds to rational action. We challenge the intuitions and expose a mathematical error in the example. We also offer (...) a model for the local interpretivist semantics. This model puts theoretical local interpretivists on ground as solid as that of Thesis abiders for whom conditionals have truth conditions. (shrink)

Michael Huemer argues, on statistical grounds, that ``existence is evidence for immortality". On reasoning derived from the anthropic principle, however, mere existence cannot be evidence against any non-indexical, ``eternal'' hypothesis that predicts observers. This note attempts to advertise the much-flouted anthropic principle's virtues and workings in a new way, namely by calling attention to the fact that it is the primary intension of one's indexically-described evidence that best characterizes one's epistemic position.

Van Fraassen's Judy Benjamin problem asks how one ought to update one's credence in A upon receiving evidence of the sort ``A may or may not obtain, but B is k times likelier than C'', where {A,B,C} is a partition. Van Fraassen's solution, in the limiting case of increasing k, recommends a posterior converging to the probability of A conditional on A union B, where P is one's prior probability function. Grove and Halpern, and more recently Douven and Romeijn, have (...) argued that one ought to leave credence in A unchanged, i.e. fixed at P(A). We argue that while the former approach is superior, it brings about a Reflection violation due in part to neglect of a ``regression to the mean'' phenomenon, whereby when C is eliminated by random evidence that leaves A and B alive, the ratio P(A):P(B) ought to drift in the direction of 1:1. (shrink)

Brief, unfinished draft of a proposal for a novel and demanding, yet arguably well motivated, necessary condition for justified credence.

A critical reading of Sarah Moss's "Probabilistic Knowledge".

We offer a critical evaluation of a recent proposal of E. Tal and J. Comesa\~na on the topic of when evidence of evidence constitutes evidence. After establishing that attempts of L. Moretti and W. Roche to discredit the proposal miss their mark, we fashion another, which does not.

A puzzle of an unmarked clock, used by Timothy Williamson to question the KK principle, was separately adapted by David Christensen and Adam Elga to critique a principle of Rational Reflection. Both authors, we argue, flout the received relationship between ideal agency and the classical distinction between systematic and random error, namely that ideal agents are subject only to the latter. As a result, these criticisms miss their mark.

Remco Heesen has recently argued in favor of the editorial practice of triple-anonymous review on the grounds that ``an injustice is committed against certain authors'' under non-anonymous review. On the other hand, he concedes that the information waste of triple-anonymous review does handicap editors, in particular sacrificing a boost in the average quality of accepted papers that would otherwise be conferred by non-anonymous review. In this paper it is observed that by devoting comparatively greater reviewing resources to the papers of (...) unfamiliar authors, editors practicing non-anonymous review can, without loss of information, avoid subjecting authors to the sorts of injustices observed by Heesen. Thus they can reap the efficiency gains of non-anonymous review without sacrificing fairness. (shrink)

Paying strict attention to Brandon Carter's several published renditions of anthropic reasoning, we present a ``nutshell'' version of the Doomsday argument that is truer to Carter's principles than the standard balls-and-urns or otherwise ``naive Bayesian'' versions that proliferate in the literature. At modest cost in terms of complication, the argument avoids commitment to many of the half-truths that have inspired so many to rise up against other toy versions, never adopting posterior outside of the convex hull of one's prior distribution (...) over the ``true chance'' of Doom. The hyper-pessimistic position of the standard balls-and-urn presentation and the hyper-optimistic position of naive self-indicators are seen to arise from dubiously extreme prior distributions, leaving room for a more satisfying and plausible intermediate solution. (shrink)

Dawid, DeGroot and Mortera showed, a quarter century ago, that any agent who regards a fellow agent as a peer--in particular, defers to the fellow agent's prior credences in the same way that she defers to her own--and updates by split-the-difference is prone to diachronic incoherence. On the other hand one may show that there are special scenarios in which Bayesian updating approximates difference splitting, so it remains an important question whether it remains a viable response to ``generic" peer update. (...) We look at arguments by two teams of philosophers against difference splitting. (shrink)

Dozens of articles have addressed the challenge that gambles having undefined expectation pose for decision theory. This paper makes two contributions. The first is incremental: we evolve Colyvan's ``Relative Expected Utility Theory'' into a more viable ``conservative extension of expected utility theory" by formulating and defending emendations to a version of this theory proposed by Colyvan and H\'ajek. The second is comparatively more surprising. We show that, so long as one assigns positive probability to the theory that there is a (...) uniform bound on the utility of possible gambles (and assuming a uniform bound on the amount of utility that can accrue in a fixed amount of time), standard principles of anthropic reasoning (as formulated by Brandon Carter) place lower and upper bounds on the expected values of gambles advertised as having no expectation--even assuming that with positive probability, all gambles advertised as having infinite expected utility are administered faithfully. Should one accept the uniform bound premises, this reasoning thus dissolves (or nearly dissolves, in some cases) several puzzles in infinite decision theory. (shrink)

Cian Dorr considered the case of a fair coin that is tossed every day throughout an infinite past and an infinite future (an ``Eternal Coin''). Against intuition, he argued that, conditional on the Coin having landed {\it heads} throughout the past, one should believe, with full probability, that it will also land {\it heads} today. In this paper, we critique Dorr's arguments, as well as part of a reply by Myrvold.

Parodic earlier draft of "Sleeping Beauty: why violations of probability laws are `Deal' breakers".

Technical criticism of Jacob Ross's "Sleeping Beauty, Countable Additivity and Rational Dilemmas" and Double Halfing.

"Beauty died today. Or maybe yesterday. I can't be sure." --Later draft of "Sleeping Beauty: A Critical Survey".

We address problems (that have since been addressed) in a proofs-version of a paper by Eva, Hartmann and Rad, who where attempting to justify the Kullback-Leibler divergence minimization solution to van Fraassen’s Judy Benjamin problem.

General criticism of Frank Arntzenius's paper ``Some problems for conditionalization and reflection''.

We introduce a ``rarity of defeat'' principle, valid in cases of deference to an expert, to address intuitions involved in a puzzle of Nissan-Rozen concerning epistemic deference and evidential screening-off.

Anti-expertise, or self-defeating belief, leads to incoherent personal credences. Some philosophers think that anti-expertise is irrational but avoidable, others think that some cases of anti-expertise are rational, and still others think that anti-expertise is irrational and unavoidable. Taking as premises some standard assumptions about the Sleeping Beauty Problem, I prove that if Beauty maintains public credences then she is prone to anti-expertise unless she embraces optimism, i.e. denies that she will experience multiple awakenings if tails.

Rambling, largely unreadable survey of the Sleeping Beauty literature.

Adam Elga has argued that holders of imprecise credences fall prey to missed arbitrages, so that rational credences should be sharp. A decision rule proposed by Rohan Sud, Forward Looking, enables imprecise Bayesians to sidestep missed arbitrages and other ``bad books'' in isolated fixed-evidence binary betting sequences such as those of Elga. We show that Forward Looking imprecise Bayesians are committed to a bad book of bets when faced with a particular 3-bet variable-evidence binary betting sequence.

Unremarkable earlier draft of "Sleeping Beauty: A Critical Survey".

Several treatments of the Shooting Room Paradox have failed to recognize the crucial role played by its involving a number of players unbounded in expectation. We indicate Reflection violations and/or Dutch Book vulnerabilities in extant ``solutions''and show that the paradox does not arise when the expected number of participants is finite; the Shooting Room thus takes its place in the growing list of puzzles that have been shown to require infinite expectation. Recognizing this fact, we conclude that prospects for a (...) ``straight solution" are dim. (shrink)

Anubav Vasudevan characterized van Fraassen’s “Infomin” solution to the Judy Benjamin Problem (i.e. the solution by way of minimizing the Kullback-Leibler divergence between the posterior and prior) as an implementation of a “brand of epistemic charity” taking “the form of an assumption on the part of Judy Benjamin that her informant’s evidential report leaves out no relevant information”. After an analysis of the example that led Vasudevan to this way of thinking about Infomin, as well as of a new one (...) that supports the rival position of Douven and Romeijn in favor of minimizing the inverse Kullback-Leibler divergence between the posterior and the prior, we come to a different and more enlightening characterization of Infomin’s implicit assumptions. (shrink)