MCMP – Epistemology

Greg Gandenberger (Pittsburgh) gives a talk at the MCMP Colloquium (22 April, 2015) titled "New Responses to Some Purported Counterexamples to Likelihoodist Principles". Abstract: The Likelihood Principle is important because the frequentist statistical methods that are most commonly used in science violate it, while rival likelihoodist and Bayesian methods do not. It is supported by a variety of arguments, including several proofs from intuitively plausible axioms. It also faces many objections, including several purported counterexamples. In this talk, I provide new responses to four purported counterexamples to the Likelihood Principle and its near-corollary the Law of Likelihood that are not adequately addressed in the existing literature. I first respond to examples due to Fitelson and Titelbaum that I argue are adequately addressed by restricting the Law of Likelihood to mutually exclusive hypotheses. I then respond to two counterexamples from the statistical literature. My responses to these latter examples are novel in that they do not appeal to prior probabilities, which is important for attempts to use the Likelihood Principle to provide an argument for Bayesian approaches that does presuppose the permissibility of using prior probabilities in science.

Kevin Zollman (CMU) gives a talk at the Conference on Agent-Based Modeling in Philosophy (11-13 December, 2014) titled "The Formation of Epistemic Networks". Abstract: One important area of study for social epistemology is the social structure epistemic groups -- who communicates their knowledge with whom? Significant research has been done on better and worse communication networks, but less has been done on how a group comes to have one network or another. In this talk, I will present a number of results (some recent) from economics and philosophy about how individuals choose with whom to communicate. Understanding how individuals decide where to gain information can help us to design institutions that lead to epistemically more reliable groups.

Elke Brendel (Bonn) gives a talk at the MCMP Colloquium (17 June, 2015) titled "Disagreement and Epistemic Modality". Abstract: Intuitively, the truth conditions of sentences with epistemic modals, such as “It might be that p”, depend on what is epistemically known by a speaker or some contextually relevant group. That is why a contextualist account of epistemic modals seems to provide an adequate semantics for epistemic modal claims. However, contextualism has difficulties to account for the intuition of disagreement about epistemic modal claims: If A claims (according to his knowledge): “It might be that p” and B claims (according to her knowledge) “It cannot be that p”, A and B seem to disagree. They are not merely talking past each other. In my talk, I will first explore the notion of disagreement and present some necessary conditions for two parties disagreeing with each other. Second, I will critically examine the prospects of contextualist semantics as well as truth-relativist accounts in dealing with disagreement about epistemic modal claims. I will finally analyze arguments in favor of an invariantist theory of epistemic modality.

Elke Brendel (Bonn) gives a talk at the MCMP Colloquium (17 June, 2015) titled "Disagreement and Epistemic Modality". Abstract: Intuitively, the truth conditions of sentences with epistemic modals, such as “It might be that p”, depend on what is epistemically known by a speaker or some contextually relevant group. That is why a contextualist account of epistemic modals seems to provide an adequate semantics for epistemic modal claims. However, contextualism has difficulties to account for the intuition of disagreement about epistemic modal claims: If A claims (according to his knowledge): “It might be that p” and B claims (according to her knowledge) “It cannot be that p”, A and B seem to disagree. They are not merely talking past each other. In my talk, I will first explore the notion of disagreement and present some necessary conditions for two parties disagreeing with each other. Second, I will critically examine the prospects of contextualist semantics as well as truth-relativist accounts in dealing with disagreement about epistemic modal claims. I will finally analyze arguments in favor of an invariantist theory of epistemic modality.

Ben Levinstein (Oxford) gives a talk at the MCMP Colloquium (6 May, 2015) titled "A Pragmatic Vindication of Epistemic Utility Theory". Abstract: Traditionally, probabilism and other norms on partial belief have been motivated from a pragmatic point of view. For instance, as Frank Ramsey long ago showed, if you're probabilistically incoherent, then you're subject to a set of bets each of which you consider fair but which are jointly guaranteed to result in a net loss. Since Joyce's seminal 1998 paper, some epistemologists have shifted course and have tried to establish norms on epistemic states without any recourse to practical rationality. I use a theorem from Schervish to bridge the gap between these two approaches. We can either take standard measures of accuracy to be formalizations of purely epistemic value, or we can generate them from what are at base practical foundations. Even if we opt for this latter approach, I show we can mostly cordon off the epistemic from the practical while ultimately grounding epistemic norms in purely practical rationality.

Ben Levinstein (Oxford) gives a talk at the MCMP Colloquium (6 May, 2015) titled "A Pragmatic Vindication of Epistemic Utility Theory". Abstract: Traditionally, probabilism and other norms on partial belief have been motivated from a pragmatic point of view. For instance, as Frank Ramsey long ago showed, if you're probabilistically incoherent, then you're subject to a set of bets each of which you consider fair but which are jointly guaranteed to result in a net loss. Since Joyce's seminal 1998 paper, some epistemologists have shifted course and have tried to establish norms on epistemic states without any recourse to practical rationality. I use a theorem from Schervish to bridge the gap between these two approaches. We can either take standard measures of accuracy to be formalizations of purely epistemic value, or we can generate them from what are at base practical foundations. Even if we opt for this latter approach, I show we can mostly cordon off the epistemic from the practical while ultimately grounding epistemic norms in purely practical rationality.

Denis Bonnay (Paris Quest/IHPST) gives a talk at the MCMP Colloquium (30 April, 2015) titled "An Axiomatization of Individual and Social Updates". Abstract: In this talk, I will consider update rules, which an agent may follow in order to update her subjective probabilities and take into account new information she receives. I will consider two different situations in which this may happen: (1) individual updates: when an agent learns the probability for a particular event to have a certain value. (2) social updates: when an agent learns the probability an other agent's gives to a particular event. Jeffrey's conditioning and weighted averaging are two famous update rules, in individual and social situations respectively. I will show that both can be axiomatized by means of one and the same invariance principle, related to Carnap's use of invariance in his work on probabilities.

Denis Bonnay (Paris Quest/IHPST) gives a talk at the MCMP Colloquium (30 April, 2015) titled "An Axiomatization of Individual and Social Updates". Abstract: In this talk, I will consider update rules, which an agent may follow in order to update her subjective probabilities and take into account new information she receives. I will consider two different situations in which this may happen: (1) individual updates: when an agent learns the probability for a particular event to have a certain value. (2) social updates: when an agent learns the probability an other agent's gives to a particular event. Jeffrey's conditioning and weighted averaging are two famous update rules, in individual and social situations respectively. I will show that both can be axiomatized by means of one and the same invariance principle, related to Carnap's use of invariance in his work on probabilities.

Greg Gandenberger (Pittsburgh) gives a talk at the MCMP Colloquium (22 April, 2015) titled "New Responses to Some Purported Counterexamples to Likelihoodist Principles". Abstract: The Likelihood Principle is important because the frequentist statistical methods that are most commonly used in science violate it, while rival likelihoodist and Bayesian methods do not. It is supported by a variety of arguments, including several proofs from intuitively plausible axioms. It also faces many objections, including several purported counterexamples. In this talk, I provide new responses to four purported counterexamples to the Likelihood Principle and its near-corollary the Law of Likelihood that are not adequately addressed in the existing literature. I first respond to examples due to Fitelson and Titelbaum that I argue are adequately addressed by restricting the Law of Likelihood to mutually exclusive hypotheses. I then respond to two counterexamples from the statistical literature. My responses to these latter examples are novel in that they do not appeal to prior probabilities, which is important for attempts to use the Likelihood Principle to provide an argument for Bayesian approaches that does presuppose the permissibility of using prior probabilities in science.

Branden Fitelson (Rutgers) gives a talk at the MCMP Colloquium (16 July, 2014) titled "Coherence".