News

CFE Workshop on the Logic of Simplicity


Sponsored by Studia Logica and the John Templeton Foundation
Center for Formal Epistemology, Carnegie Mellon University.

June 7-9 2013

Location: Adamson Wing, Baker Hall, CMU Campus

All are invited to attend. CMU Summer School attendees are paraticularly welcome.

Rationale: Ockham's razor is the characteristic bias toward simple hypotheses that has characterized scientific inquiry since Copernicus.  But what is it, exactly?  This workshop aims to revisit that question from a fresh logical perspective.  Potential candidates for the simplicity order include dimensionality, Kolmogorov complexity, and VC dimension.  Candidates for Ockham's razor, itself, include logical theories for revising belief in light of such an order in the deterministic case and a host of model selection methods on the side of statistics and machine learning.   This interdisciplinary workshop will begin to explore a number of new and interesting logical questions at the interface of logic and scientific method.  Which orders are simplicity orders?   Is simplicity relative to questions or subject to other framing effects?  How should a simplicity order be modified in light of new information?  What may one believe in light of a simplicity order and given information?  What should one do if the simplicity order branches?   Are the essential features of a simplicity order preserved by the associated belief revision rule?  Are standard belief revision principles descriptively plausible in scientific applications?  Is simplicity absolute or relative to framing effects?  Is there any normative reason to revise according to simplicity rather than some other principle?  Addressing these fundamental questions promises both to sharpen our conception of scientific method and to broaden our ideas about the logic of belief revision.

Invited speakers:

Alexandru Baltag(ILLC Amsterdam)

James Delgrande (Simon Fraser University Computer Science)

Nina Gierasimczuk(ILLC Amsterdam)

Sven Ove Hannson (University of Stockholm, Philosophy)

Kevin T. Kelly (Carnegie Mellon University, Philosophy)

Hanti Lin(Carnegie Mellon University, Philosophy)

Eric Martin (University of New South Wales Computer Science)

Oliver Schulte (Simon Fraser University Computer Science)

Sonja Smets (ILLC Amsterdam)

Peter Spirtes(Carnegie Mellon University, CMU)

2nd Conference on Games, Interactive Rationality, and Learning (GIRL)

April 23-26, 2013

Lund, Sweden

Cosponsored by the CFE

Conference web site

CFE Workshop on Cognition and Formal Theories of Reasoning

March 30, 2013

Location: Wean Hall 4625, Carnegie Mellon University

All are invited to attend

Program:

9:00 Niki Pfeifer (LMU & CFE Visiting Fellow)

How People (Ought to) Reason under Uncertainty

Abstract: Mental probability logic" (MPL) consists of normative and descriptive theory components. The normative one is based on coherence based probability logic. It formulates reasoning problems in terms of arguments consisting of premises and conclusions. The uncertainty of the premises is transmitted deductively to the conclusion. The descriptive component of MPL investigates empirical hypothesis which are made precise by MPL's normative theory component. In my talk I show how the normative and descriptive theory elements of MPL interact. I illustrate my approach with selected formal and empirical work on nonmonotonic reasoning, Aristotle's thesis, and first steps towards a coherence based probability semantics of Aristotelian syllogisms.

10:10 Hanti Lin and Kevin T. Kelly (CMU Philosophy)

Propositional Beliefs that Aptly Represent Subjective Probabilities in Light of New Information

Abstract: If Bayesians are right, one's doxastic state should be modeled by subjective probabilities.  But in traditional epistemology, in logic-based artificial intelligence, and in everyday life, one's doxastic state is usually expressed in a qualitative, binary way: either one accepts (believes) a proposition or one does not.  What is the relationship between qualitative and probabilistic belief?  A standard approach is to identify propositional belief with certainty (Levi 1967, Douven 2002) or near certainty (Kyburg 1961, Foley 1992, Weinstraub 2001). But that is too skeptical---one reasons and plans all the time with propositions that fall short of near-certainty: e.g., that the grocery store will be open after work. We present an alternative viewpoint according to which propositional beliefs should crudely but aptly represent one's probabilistic credences in terms of propositions. Aptness should include responses to new information: if propositional belief state K aptly represents degrees of belief p then the revised belief state K*E should aptly represent the conditional degrees of belief p(.|E). We explain how to characterize synchronic aptness and qualitative belief revision to ensure diachronic aptness in the sense just defined. We also show that diachronic aptness in the sense just described is impossible if acceptance is based on thresholds or if qualitative belief revision is based on the familiar AGM belief revision theory of Alchourron, Gardenfors, and Makinson 1985.

10:20 Wilfried Sieg (CMU Philosophy)

Structural Proof Theory: Uncovering Capacities of the Mathematical Mind?

Abstract: What is it that shapes arguments into mathematical proofs that are intelligible to us, and what is it that allows us (or machines) to find proofs efficiently? – These are the informal questions I intend to address. Two aspects of mathematical experience play a significant role: the abstract ways of the axiomatic method used in modern mathematics and the concrete ways of proof construction suggested by modern proof theory. The subtle interaction between understanding and reasoning, i.e., between introducing concepts and proving theorems, is crucial and suggests principles for structuring proofs conceptually. My partly historical and partly theoretical investigations are complemented by experimentation with a strategically guided proof search algorithm. The issues will be illustrated by considering three theorems and their proofs: the Pythagorean theorem, the Cantor Bernstein theorem, and Goedel's incompleteness theorem.

12:20 Lunch

2:30 Chris Lucas (CMU Psychology)

Bayes net Models of Counterfactual Reasoning

Abstract: Bayesian networks have been used to account for many aspects of causal reasoning, including inferences about counterfactual scenarios. We present a Bayes net model of counterfactual reasoning that generalizes and extends the work of Pearl (2000). The model distinguishes between counterfactual observations and counterfactual interventions, and can reason about both backtracking and non-backtracking counterfactuals. Several experiments demonstrate that our model accounts better for human inferences than Pearl's original proposal and a more recent Bayes net account developed by Rips (2009).

3:40 Charles Kemp and Chris Carroll (CMU Psychology)

Hypothesis Space Checking in Everyday Reasoning

Abstract: The process of discovering a new hypothesis often begins with the recognition that all of the hypotheses currently under consideration are wrong. While this sort of falsification is straightforward when the observations are strictly incompatible with the hypotheses, a more challenging situation arises when the observations are implausible under the hypotheses but not incompatible with them. We propose a formal account, inspired by falsificationism and statistical model checking, as an explanation for how people decide that all of their current hypotheses are probably wrong. In our talk, we will describe a psychology experiment that contrasted this account with Bayesian inference. We conclude that although Bayesian reasoning can explain inference within a given hypothesis space, it cannot explain how people decide that they need to look beyond their current hypothesis space.

4:40 David Danks (CMU Philosophy)

Discussion: Logic, Psychology, and Reasoning"

Abstract: I will synthesize the preceding talks and set the stage for an extended discussion among all participants.

5:50 Program concludes

CFE Ockham Workshop streaming videos now online

Visit the Ockham workshop web page.

Recent Events

October 6, 2012, CFE Conference: "Evolution, Learning, and Games".

Location: Wean Hall 4625, Carnegie Mellon University

  • 12:00 Lunch
  • 2:00 Rory Smead (Northeastern University)
  • Two Evolutionary Models of Unconditional Spite
  • [MP4]
  • 3:30 Russell Golman (Carnegie Mellon University)
  • Basis of Attraction and Equilibrium Selection with Population Learning Dynamics
  • [MP4]
  • 5:00 Final Thoughts

August 2-4, Tribute to Horacio Arlo-Costa, Sociedad Argentina De Analisis Filisofico, Buenos Aires.

Speakers:

  • Lavinia Picollo (Universidad de Buenos Aires - CONICET - GAF)
  • Dustin Tucker (Texas Tech University)
  • Vit Puncochar (Faculty of Arts, Charles University in Prague)
  • Diego Tajer (Universidad de Buenos Aires – CONICET)
  • John Collins (Columbia University):
  • Javier Legris and Silvia Lerner (Universidad de Buenos Aires)
  • Claudio Alessio (Universidad Católica de Cuyo)
  • Paul Pedersen (Carnegie Mellon University)
  • Lucas Rosenblatt (Universidad de Buenos Aires – CONICET – GAF)
  • Gustavo Bodanza (Universidad Nacional del Sur)
  • Verónica Becher (Universidad de Buenos Aires)
  • Marcelo Auday and Rodrigo Moro (Universidad Nacional del Sur –
    CONICET)
  • David Etlin (University of Groningen)
  • Kevin Kelly (Carnegie Mellon University)

Program

An Interdisciplinary CFE Workshop on the Foundations of Ockham's Razor was held on June 22-24, 2012, Adamson Wing, Baker Hall, Carnegie Mellon University

Rationale:

Scientific theory choice is guided by judgments of simplicity, a bias frequently referred to as "Ockham's Razor". But what is simplicity and how, if at all, does it help science find the truth? Should we view simple theories as means for obtaining accurate predictions, as classical statistics and machine learning urge? Or should we believe the theories themselves, as Bayesian methods seem to justify? The aim of this workshop is to re-examine the foundations of Ockham's razor, with a firm focus on the connections, if any, between simplicity and truth.

Speakers:

Streaming videos and slides available at the workshop web page

The CFE co-sponsored the First CSLI Workshop on Logic, Rationality and Interaction.

June 1-3, 2012, Cordura Hall, CSLI, Stanford Universtiy

Organizers:

Johan van Benthem, Peter Hawke, Wes Holliday, Tomohiro Hoshi, Thomas Icard, Shane Steinert-Threlkeld.

Speakers:

Workshop web page

The CFE co-sponsored the GIRL (Games, Interactive Rationality, and Learning) conference at the University of Lund, Sweden, on April 19-21, 2012, organized by Emmanuel Genot, Justine Jacot, and Philip Paernamets.

Workshop web page.

Horacio Arlo-Costa
(1956-2011)

Commemorative Collection for Horacio Arlo-Costa. To honor Horacio Arlo-Costa's memory and influence on all of us in the community, Jeffrey Helzner, Vincent F. Hendricks, Paul Pedersen and Gregory Wheeler will be editing a book with essays on his philosophy, his intellectual biography, his official obituary, words of remembrance from his friends and colleagues, his unpublished manuscripts and notes, and other relevant communications from or about Horacio. If you have words of remembrance, please feel welcome to post them at Choice and Inference under the entry In Memory of Horacio Arlo-Costa, as we will, with your permission, use your words of remembrance for the volume. Please send all other material (correspondences, notes, etc.) to any one of the editors:

In Memoriam: Horacio Arlo-Costa (1956-2011). We deeply regret the sudden passing of CFE Associate Director Horacio Arlo-Costa. The Center's ambitious schedule of six events in its first year of operation was due in large part to Horacio's indefatigable dedication. His stature in formal epistemology is familiar. His tireless enthusiasm, his widespread connections in the field and his renowned, encyclopedic knowledge of the literature and the contributions of others made him an indespensable partner in the wild adventure that constituted the Center's crucial first year of operation. He will be missed sorely. In spite of his many other duties and concerns, Horacio reveled in the CFE's rapid expansion . To vindicate his commitment, the CFE will redouble its efforts to facilitate the cause of formal philosophy in the coming years.

Horacio's obituary

Horacio's funeral arrangements

Horacio's CFE legacy

The Commemorative Colloquium for CFE Associate Director Horacio Arlo-Costa was held on November 19-20, 2011. Thanks to all the speakers for making the Colloquium a great success! Here is the schedule of talks.

The CFE workshop In Search of Answers: The Guiding Role of Questions in Discourse and Epistemology was held on Nov 5, 2011 in 4625 Wean Hall

Schedule and abstracts.

Speakers:

Jeroen Groenendijk, University of Amsterdam
Craige Roberts, Ohio State University
Mandy Simons, Carnegie Mellon University
Hanti Lin, Carnegie Mellon University
Kevin T. Kelly, Carnegie Mellon University

The Episteme annual conference on Social Epistemology was held at the CFE on June 24-26, 2011 in coordination with Alvin Goldmanand Christian List.  Here is the revised schedule and a link to arrangements.

There was a joint CSLI-CFE-San Francisco State workshop on Logic and Formal Epistemology at CSLI, Stanford on May 14 and 15, 2011, organized by Johan van Benthem, Bas van Fraassen, and Kevin van Kelly.  The topics will be learning in epistemic logic and a re-examination of norms in empirical reasoning. Local organizers Peter Hawke, Wes Holliday, Tomohiro Hoshi, and Thomas Icard at Stanford did a fantastic job and the workshop was supported mainly by the generosity of Patrick Suppes and the Department of Philosophy at Stanford. We hope this is the beginning of a long tradition.

On March 16, 12:00-4:00 there was a symposium on uncertain acceptance involving Hannes Leitgeb, Horacio Arlo-Costa, Kevin Kelly, Paul Pedersen, and Hanti Lin in DH.  The symposium compared notes on three new but distinct approaches to the subject. 

The CFE Colloquium series for Spring 2011 was rich, varied, and exciting.  Speakers included Cosma Shalizi, Michiel van Lambalgen, Hannes Leitgeb, Anil Gupta, and Mic Detlefsen.

The workshop on Experience, Heuristics, and Choice: Prospects for Bounded Rationality on Dec 1, 2010 was a great success.  Thanks to all who participated.

The 2010 Nagel Lectures were delivered by Brian Skyrms on Oct. 19-21, 2010.
The CFE Opening Celebration Conference was held on June 26-27, 2010.  Thanks to all who contributed to make it such a huge success!


The CFE Masthead illustrates Doherty Hall,where the new CFE office wing is located  (the windows on the top floor).  Like most of the Carnegie Mellon Campus, Doherty hall was designed in the Beaux-arts style by American architect Henry Hornbostel (1867-1961).  The band across  the bottom of the masthead is taken from the terra-cotta thistle frieze, designed to commemorate Andrew Carnegie, that runs right below the windows of the CFE offices.

Center Overview

In October 2009, the Center for Formal Epistemology was founded to promote research and educational exchanges in Formal Epistemology worldwide. The Center adopts a broad perspective on Formal Epistemology, including philosophically and formally informed, interdisciplinary work in the following areas:

  • bayesian epistemology,
  • belief revision,
  • causation,
  • decision and game theory,
  • philosophical logic (conditional, epistemic, erotetic, dynamic, etc.),
  • formal learning theory,
  • formal approaches in cognitive science,
  • formal theories in the philosophy of science,
  • history of formal epistemology,
  • implicature and pragmatics,
  • philosophy of mathematics,
  • philosophy of statistics,
  • social epistemology.

    • Center activities include:

  • a Visiting Fellows program,
  • a graduate exchange program,
  • a Summer School in Logic and Formal Epistemology for prospective graduate students,
  • an annual, Focused Workshop in Formal Epistemology that rotates in topic,
  • an annual Colloquium Series in Formal Epistemology.