MCMP – Epistemology

Branden Fitelson (Rutgers) meets Hannes Leitgeb (MCMP/LMU) in a joint session on "Belief vs Probability" at the MCMP workshop "Bridges 2014" (2 and 3 Sept, 2014, German House, New York City). The 2-day trans-continental meeting in mathematical philosophy focused on inter-theoretical relations thereby connecting form and content of this philosophical exchange. Idea and motivation: We use theories to explain, to predict and to instruct, to talk about our world and order the objects therein. Different theories deliberately emphasize different aspects of an object, purposefully utilize different formal methods, and necessarily confine their attention to a distinct field of interest. The desire to enlarge knowledge by combining two theories presents a research community with the task of building bridges between the structures and theoretical entities on both sides. Especially if no background theory is available as yet, this becomes a question of principle and of philosophical groundwork: If there are any – what are the inter-theoretical relations to look like? Will a unified theory possibly adjudicate between monist and dualist positions? Under what circumstances will partial translations suffice? Can the ontological status of inter-theoretical relations inform us about inter-object relations in the world? Find more about the meeting at www.lmu.de/bridges2014.

Alvin I. Goldman (Rutgers) meets Stephan Hartmann (MCMP/LMU) in a joint session on "Bridging the Gap between Informal and Formal Social Epistemology" at the MCMP workshop "Bridges 2014" (2 and 3 Sept, 2014, German House, New York City). The 2-day trans-continental meeting in mathematical philosophy focused on inter-theoretical relations thereby connecting form and content of this philosophical exchange. Idea and motivation: We use theories to explain, to predict and to instruct, to talk about our world and order the objects therein. Different theories deliberately emphasize different aspects of an object, purposefully utilize different formal methods, and necessarily confine their attention to a distinct field of interest. The desire to enlarge knowledge by combining two theories presents a research community with the task of building bridges between the structures and theoretical entities on both sides. Especially if no background theory is available as yet, this becomes a question of principle and of philosophical groundwork: If there are any – what are the inter-theoretical relations to look like? Will a unified theory possibly adjudicate between monist and dualist positions? Under what circumstances will partial translations suffice? Can the ontological status of inter-theoretical relations inform us about inter-object relations in the world? Find more about the meeting at www.lmu.de/bridges2014.

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

Teddy Seidenfeld (CMU) gives a talk at the Workshop on Imprecise Probabilities in Statistics and Philosophy (27-28 June, 2014) titled "Dominance and Elicitation in IP Theory". Abstract: I review de Finettis two coherence criteria for determinate probabilities: coherence1, which is defined in terms of previsions (fair prices) for a set of random variables that are undominated by the status quo previsions immune to a sure-loss and coherence2, which defined in terms of forecasts for random variables that are undominated in Brier score by a rival set of forecasts. I review issues of elicitation associated with these two criteria that differentiate them, particularly when generalizing from eliciting determinate to eliciting imprecise probabilities.

Fabio G. Cozman (Sao Paulo) gives a talk at the Workshop on Imprecise Probabilities in Statistics and Philosophy (27-28 June, 2014) titled "Imprecise (Full Conditional) Probabilities, Graphs and Graphoids Independence Assumptions". Abstract: Research in artificial intelligence systems has often employed graphs to encode multivariate probability distributions. Such graph-theoretical formalisms heavily employ independence assumptions so as to simplify model construction and manipulation. Another line of research has focused on the combination of logical and probabilistic formalisms for knowledge representation, often without any explicit discussion of independence assumptions. In this talk we examine (1) graph-theoretical models, called credal networks, that represent sets of probability distributions and various independence assumptions; and (2) languages that combine logical constructs with graph-theoretical models, so as to provide tractability and exibility. The challenges in combining these various formalisms are discussed, together with insights on how to make them work together.

Jim Joyce (Michigan) gives a talk at the Workshop on Imprecise Probabilities in Statistics and Philosophy (27-28 June, 2014) titled "Imprecise Priors as Expressions of Epistemic Values". Abstract: As is well known, imprecise prior probabilities can help us model beliefs in contexts where evidence is sparse, equivocal or vague. It is less well-known that they can also provide a useful way of representing certain kinds of indecision or uncertainty about epistemic values and inductive policies. If we use the apparatus of proper scoring rules to model a believer's epistemic values, then we can see her 'choice' of a prior as, partly, an articulation of her values. In contexts where epistemic values and inductive policies are less than fully definite, or where there is unresolved conflict among values, the imprecise prior will reject this indefiniteness in theoretically interesting ways.

Jim Joyce (Michigan) gives a talk at the Workshop on Imprecise Probabilities in Statistics and Philosophy (27-28 June, 2014) titled "Imprecise Priors as Expressions of Epistemic Values". Abstract: As is well known, imprecise prior probabilities can help us model beliefs in contexts where evidence is sparse, equivocal or vague. It is less well-known that they can also provide a useful way of representing certain kinds of indecision or uncertainty about epistemic values and inductive policies. If we use the apparatus of proper scoring rules to model a believer's epistemic values, then we can see her 'choice' of a prior as, partly, an articulation of her values. In contexts where epistemic values and inductive policies are less than fully definite, or where there is unresolved conflict among values, the imprecise prior will reject this indefiniteness in theoretically interesting ways.

Fabio G. Cozman (Sao Paulo) gives a talk at the Workshop on Imprecise Probabilities in Statistics and Philosophy (27-28 June, 2014) titled "Imprecise (Full Conditional) Probabilities, Graphs and Graphoids Independence Assumptions". Abstract: Research in artificial intelligence systems has often employed graphs to encode multivariate probability distributions. Such graph-theoretical formalisms heavily employ independence assumptions so as to simplify model construction and manipulation. Another line of research has focused on the combination of logical and probabilistic formalisms for knowledge representation, often without any explicit discussion of independence assumptions. In this talk we examine (1) graph-theoretical models, called credal networks, that represent sets of probability distributions and various independence assumptions; and (2) languages that combine logical constructs with graph-theoretical models, so as to provide tractability and exibility. The challenges in combining these various formalisms are discussed, together with insights on how to make them work together.

Teddy Seidenfeld (CMU) gives a talk at the Workshop on Imprecise Probabilities in Statistics and Philosophy (27-28 June, 2014) titled "Dominance and Elicitation in IP Theory". Abstract: I review de Finettis two coherence criteria for determinate probabilities: coherence1, which is defined in terms of previsions (fair prices) for a set of random variables that are undominated by the status quo previsions immune to a sure-loss and coherence2, which defined in terms of forecasts for random variables that are undominated in Brier score by a rival set of forecasts. I review issues of elicitation associated with these two criteria that differentiate them, particularly when generalizing from eliciting determinate to eliciting imprecise probabilities.

Gregory Wheeler (MCMP) gives a talk at the MCMP Colloquium (25 June, 2014) titled "Fast, Frugal and Focused: When less information leads to better decisions". Abstract: People frequently do not abide by the total evidence norm of classical Bayesian rationality but instead use just a few items of information among the many available to them. Gerd Gigerenzer and colleagues have famously shown that decision-making with less information often leads to objectively better outcomes, which raises an intriguing normative question: if we could say precisely under what circumstances this "less is more" effect occurs, we conceivably could say when people should reason the Fast and Frugal way rather than the classical Bayesian way. In this talk I report on results from joint work with Konstantinos Katsikopoulos that resolves a puzzle in the mathematical psychology literature over attempts to to explain the conditions responsible for this "less is more" effect. What is more, there is a surprisingly deep connection between the "less is more" effect and coherentist justification. In short, the conditions that are good for coherentism are lousy for single-reason strategies, and vice versa.