Carnegie Mellon University

2012-2013 Lectures & Colloquia


January 24, 2013, Philosophy Colloquium

Thomas Icard, Stanford University
Determining What Follows from What: Two Case Studies

Abstract: Part of being a competent speaker of a language is being "properly attuned" to logical relations between sentences in the language. A question of foundational interest in semantics is: Which logical relations are relevant to the study of linguistic meaning, and how should they be characterized? Furthermore, what does it mean to be "properly attuned" to such relations? I will present two case studies based on my recent work that bear on these questions: the first on so called probability operators such as 'probably' and 'at least as likely as'; the second on "surface level" inference patterns that are easily detectable and closely associated with grammatical phenomena. One of the general aims will be to demonstrate novel ways in which technical results in logic and related areas can both clarify debates, and lead to new ideas and discoveries, in the study of natural language. Connections to psychology of reasoning and computational linguistics will also be discussed.

January 28, 2013, Philosophy Colloquium

Olivier Roy, Munich Center for Mathematical Philosophy
What should I do? What should I expect? On Rational Requirements in Strategic Interaction

Abstract: In strategic interaction, like in any decision-making situations, questions of practical rationality - what should I do? - and questions of epistemic rationality - what should I believe? - naturally arise. In this talk I will sketch two logical approaches to study these questions. On the one hand, I will use deontic logic to study practical, rational recommendations in games. On the other hand, I will use dynamic epistemic logic to formulate "procedural" rationality constraints on practical deliberation, viewing rational beliefs in games as fixed-point interactive deliberative processes. The general picture will be that, taken together, these tools bring us closer to a general theory of rationality in games, one that encompasses both practical and theoretical requirements of rationality on the players. This talk is based on join work with Eric Pacuit (Maryland and Tilburg), Albert Anglberger (LMU Munich) and Norbert Gratzl (LMU Munich).

January 31, 2013, Philosophy Colloquium

Alexandru Radulescu, UCLA
The Difference between Indexicals and Demonstratives

Abstract: There are two kinds of context sensitive words: indexicals (e.g. "I" and "today) and demonstratives (e.g. "this" and "that"). I argue that the difference between them lies in the role played by the speaker's intentions in providing them with a semantic value in a given context. The traditional view, which actually comes in many flavors, would have it that the need for intentions of any kind indicates that the word in question is a demonstrative. I argue that my criterion fits better with the natural account of the second person singular pronoun "you", and that it helps solve two conceptual problems which have until now plagued every logic of demonstratives. This allows me to then sketch a logic of demonstratives which accounts for the validity of arguments which take place in conversations (that is, arguments in which the speaker, the addressee, the place, the time, etc. may change).

February 4, 2013, Philosophy Colloquium

Felipe De Brigard, Harvard University
Memory and Hypothetical Thinking

Abstract: Traditionally, and for a variety of reasons, philosophers have considered memory and imagination as two different cognitive faculties. But this was not always the case. Some empiricist philosophers thought of imagination and memory as intimately interconnected; Hume, for instance, suggested that memory and imagination shared some basic operations, and Hobbes went as far as saying that both were, in reality, one and the same psychological process. Recent scientific evidence appears to lend credence to the empiricists' view, as a number of recent studies show that our capacity to entertain certain hypothetical thoughts-such as thoughts about what might happen in our future (i.e., episodic future thinking) or what could have happened in our past (i.e., episodic counterfactual thinking)-largely depend on the same cognitive and neural mechanisms employed for remembering what happened in the past. However, the precise way in which different memory systems interact with different types of hypothetical thoughts is still unclear. In this talk I will offer some evidence suggesting that episodic and semantic memory systems are differentially recruited depending on the nature of the content of the hypothetical thought. Additionally, it will be shown that the involvement of such systems is modulated by the participant's sense of plausibility of the imagined event, and also that certain memory-related manipulations elicit differential effects on subjective estimations of plausibility for different kinds of hypothetical thoughts. Finally, it will be suggested that some hypothetical thoughts may play an "editorial" function in our lives, effectively curbing the emotion with which we tend to remember certain life events, whereas others may play a social role, helping us in the process of thinking what we could have done had we been in someone else's shoes. At the end, I will offer a view-rather congenial with Hume's-according to which these varieties of hypothetical thoughts can be traced back to the memory processes they mostly rely on, as well as certain essential features of the memorial contents with which they operate.

February 7, 2013, Philosophy Colloquium

Wes Holliday, University of California at Berkeley
Mathematizing Mainstream Epistemology

Abstract: This talk describes a project of mathematizing mainstream epistemology: developing model-theoretic formalizations of traditional theories of knowledge, exploring their properties through general mathematical results (completeness theorems, representation theorems, impossibility results), and using such results as a guide to new pictures of knowledge without the problems of past theories. The first part of this project is carried out in my "Epistemic Closure and Epistemic Logic I: Relevant Alternatives and Subjunctivism" (Journal of Philosophical Logic, forthcoming), available at

February 28, 2013, Philosophy Colloquium

Eric Margolis, University of British Columbia
A Nativist Perspective on Human Concepts

Abstract: In this talk, I will revisit the debate about innate ideas and will defend a nativist perspective on the origins of human concepts. Many contemporary discussions conflate nativism with the view that all concepts are innate--a view better known as “radical concept nativism”. I will offer a more plausible construal of nativism and will explain and defend a number of crucial arguments for embracing a nativist framework.

March 18, 20 & 22, 2013,

Ernest Nagel Lectures in Philosophy and Science

Please click here for documentation of the Ernest Nagel Lectures.

March 21, 2013, Philosophy Colloquium

Marloes Maathius, ETH Zurich
Estimating causal effects in high-dimensional systems

Abstract: We present recent progress on estimating bounds on causal effects from observational data, when assuming that these data are generated from an unknown directed acyclic graph. In particular, we present the IDA algorithm for this purpose. IDA is computationally feasible and consistent for high-dimensional sparse systems with many more variables than observations. We validated IDA in biological systems, and will present results on a yeast gene expression data set. Finally, we discuss possible instability issues in high-dimensional settings, as well as extensions towards allowing for hidden variables.

March 28, 2013, Philosophy Colloquium

Peter Koepke, Mathematical Institute, Bonn
Felix Hausdorff and the Foundations of Mathematics
Set Theory and Selective Formalism

Abstract: The crucial moves towards modern mathematics and logic took part during Felix Hausdorff's time. Hausdorff made seminal contributions to Cantorian set theory. In his monograph Grundzüge der Mengenlehre (Foundations of Set Theory) he advocated set theory as a universal foundation of mathematics. Hausdorff followed David Hilbert's axiomatic method and formalism. Although working with intuitive and "naive" notions of sets and other mathematical objects, Hausdorff was careful in his proofs to only refer to the formal properties of objects. Hausdorff's formalist position corresponds to the anti-metaphysical philosophy in his book Das Chaos in kosmischer Auslese (Chaos in Cosmic Selection). One might view mathematics as facing a chaos of mathematical objects out of which creative intellects select interesting theories and structures through the formulation of consistent axiom systems, guided by subjective, intuitive, pragmatic, aesthetic or other criteria. In my talk I shall also give some biographical information on Felix Hausdorff and on the edition of his collected works.

April 11, 2013, Philosophy Colloquium

Frederic Schick, Emeritus, Rutgers
Seeing in Perspective

Abstract: This paper is about painting, about perspective and seeings. I start with Alberti's rules of perspective. These are now almost 600 years old but are still widely endorsed. I will lay them out in detail as rules of representation, rules of the representation of a scene the painter is now seeing, of that scene as he sees it - which was how Alberti thought of them. The paper considers the concept of seeing involved in this idea, the concept of seeing x as y; such seeings I call cognitive. The questions to be addressed are these: what warrants the endorsement of these rules (or any other rules) of perspective, and what warrants the way people (cognitively) see things? Are there any meta-rules for the endorsement of such rules and seeings?

Other topics to be considered. How does the concept of expression relate to that of the representation of a scene - and, more basically, what is expression? A central concept for Alberti is that of the painter's viewpoint, the situation from which a scene is observed. What enters into that concept, and how do changes of viewpoint affect what the observer sees? Also, what is assent to a painting, and how does that bear on how a painting or a scene or what is in it are seen?

April 25, 2013, Philosophy Colloquium

Russell Poldrack, University of Texas at Austin
Relating neural and mental representations using neuroimaging

Abstract: I will discuss a set of studies that have examined the similarity of activity patterns evoked by different stimuli, in order to understand how mental representational spaces are instantiated in the brain. In particular, I will discuss how pattern similarity analyses can be used to directly test claims made by psychological theories. Analyses of the similarity of neural patterns show that global similarity computations, which have long been central to psychological theories of memory and categorization, are predictive of behavior across multiple task contexts. I will also show how the similarity between patterns over time relates to later memory, which provides insights into the psychological mechanisms of learning. Together these results provide a means by which to bridge between psychological and neural theories.

May 2, 2013, Philosophy Colloquium

Aki Kanamori, Boston University
Aspect Perception and the History of Mathematics

Abstract: An account of the indviduation of proofs and methods for some fundamental results of ancient and modern mathematics, from Old Babylonia to modern set theory.

Framing the discussion will be the idea of {\it seeing an aspect}: the projecting, lifting, or perspicuously presenting of a particular argument or method to construe one mathematical move or approach or procedure within another. This perspective opens up a way of seeing the shaping of necessity and of generality, and sheds light on the nature of mathematics as a whole.