Carnegie Mellon University

Lectures & Colloquia

Fall 2018


Thursday, October 11Center for Ethics and Policy Colloquium
Bertram Malle, Brown University
Talk title: When Do and Should People Trust Robots?
4:30-5: 45 pm, Baker Hall A53 Steinberg Auditorium

Abstract: The empirical literature on human trust in artificial agents such as robots is perplexing. People seem to overtrust such agents in some circumstances and undertrust them in other circumstances. Moreover, what trust is and how it is measured shows a great deal of variability. To help advance our knowledge in this domain I offer two proposals. First, I argue that trust is multi-dimensional and that humans can have familiar kinds of trust in a robot (i.e., in its reliability and capacity) but that the more interesting kinds of trust are of a moral kind (i.e., sincerity and ethical integrity). I show that these distinct dimensions of trust can be reliably measured and thus offer a fresh start in understanding when people will trust robots and other artificial agents. Second, if some dimensions of trust involve moral capacities, then we need to ask if and how robots can have moral capacities. To this end, I offer theoretical arguments and empirical evidence to propose that moral competence consists primarily of a massive web of norms, decisions in light of these norms, judgments when such norms are violated, and a vocabulary to communicate about these norm violations. I argue that future robots can in principle exhibit these capacities, and if they do so reliably, they will deserve human trust.

Thursday, October 18 -  Philosophy Colloquium
Sonja Smets, Institute for Logic, Language and Computation, University of Amsterdam
Talk Title: Logical Dynamics in Social Networks - The flow of information is what drives our information society of interconnected agents capable of reasoning, communicating and learning.
4:30 – 5:45 pm, Baker Hall A53 – Steinberg Auditorium

Abstract: In this context, we are interested in the logical study of how information flows in social networks by focusing on the spread of behaviors, ideas and the adoption of social norms. To model these diffusion processes as well as the long-term informational evolution of social networks, we make use of the tools of Dynamic Epistemic Logic (DEL). The logic DEL, originally designed to model the epistemic and doxastic states of agents, their interaction and change, has recently been enriched with a social dimension and can be applied to the modeling of various social phenomena including social influence and herd behavior. In our setting, we first consider agents who adopt a new fashion or behavior depending on whether they know that a “strong enough group” of their neighbors already has adopted. We provide different types of models as well as a simple qualitative modal language to reason about the concept of a “strong enough” trigger of influence. When we extend our logic with fixed-point operators, important results from network theory about the characterization of cascades follow immediately as a straightforward consequence of the basic axioms. Unfolding the influence dynamics in an epistemic social network allows us to characterize the epistemic conditions under which the dynamic process can speed up or slow down. This presentation is based on joint work with A. Baltag at the University of Amsterdam.

Thursday, October 25Pure and Applied Logic Colloquium
Liron Cohen, Cornell University
Talk Title: Enhancing the Proofs-as-Programs Paradigm with Modern Notions of Computation and Reasoning Techniques
4:30-5:45pm, Baker Hall A53 Steinberg Auditorium

Abstract: The proofs-as-programs paradigm which establishes a correspondence between formal proofs and computer programs has made a tremendous impact on the world of computing, enabling various high-value applications in different areas of computer science. However, while both proof theory and programming languages have evolved significantly over the past years, the cross-fertilization of the independent new developments in each of these fields has yet to be explored in the context of the paradigm. This naturally gives rise to the following questions: how can modern notions of computation influence and contribute to formal foundations, and how can modern reasoning techniques improve the way we design and reason about programs? In this talk, we focus on the first question and demonstrate how by using programming principles that go beyond the standard lambda-calculus, namely state and non-determinism, it is possible to provide new insights into foundational mathematical concepts, namely free choice sequences and the Axiom of Choice.

Thursday, November 1 -  Philosophy Colloquium
Larry Moss, Indiana University at Bloomington
Talk Title: Natural Logic
4:30 – 5:45 pm, Baker Hall A53 – Steinberg Auditorium

Abstract: Much of modern logic originates in work on the foundations of mathematics. My talk reports on work in logic that has a different goal, the study of inference in language. This study leads to what I will call "natural logic", the enterprise of studying logical inference in languages that look more like natural language than standard logical systems. I will sketch the history of this field, and I also will try to make as many connections as possible to work by the CMU community, broadly considered. For example, we have computer programs which can carry our small but significant entailment tasks on language "in the wild", and this work calls on syntax (categorial grammar, but extended), semantics (typed lambda calculus, again extended), logic, and algorithms. We also have new tools for teaching basic logic that come from this area.

The talk should appeal to mathematical logicians interested in completeness and complexity results, including ones for logical systems that are not first-order; philosophers of logic curious about syllogistic reasoning and its many modern extensions, and also about taking inference seriously in the foundations of semantics; and computer scientists working in natural language processing and especially in textual entailment.

Thursday, November 15 -  Philosophy Colloquium
Iris van Rooij, Radboud University
Talk Title: Can heuristics make hard work light? Ecological rationality and intractability
4:30 – 5:45 pm, Baker Hall A53 – Steinberg Auditorium

Abstract: Ecological rationality and intractability
Classical accounts of rationality, based on logic and probability theory, have been criticized for assuming demonic computational powers far beyond the capacity of mortals and machines. According to these accounts, rational minds must have the capacity for solving intractable (NP-hard) problems, for which no tractable algorithms exist. On an alternative account, the mind’s adaptive toolbox consists of fast and frugal heuristics and rationality is to be understood as the fit between these heuristics and the environment, called ‘ecological rationality’. It has been tacitly assumed that ecological rationality is tractable. However, as I will demonstrate in this talk, ecological rationality presents minds (or nature) with the same kind of intractable problems as classical accounts of rationality. This wrinkle may be ironed out, but doing so seems to require an extension of the heuristics research program to understand the tractability of adapting toolboxes of heuristics.