报告人：Joseph Y. Halpern (Professor of Computer Science, Cornell University)

简介：Joseph Y. Halpern是当今世界最著名的逻辑学家之一。康奈尔大学计算机系教授，美国人工智能协会 (AAAI)、美国计算机学会(ACM)、 美国艺术与科学研究院(AAAS) 院士。长期担任康奈尔大学计算机系主任。从事逻辑学与计算机科学的交叉研究。在认知逻辑、博弈论、关于因果性和不确定性等方面有独创性研究成果。

第一次讲座

时间：2017年10月25日晚 7：00--9：00

地点：清华大学主楼327

讲座题目：Actual Causality: A Survey

主持人：Johan van Benthem （清华大学金岳霖讲席教授）

摘要： What does it mean that an event C "actually caused" event E? The problem of defining actual causation goes beyond mere philosophical speculation. For example, in many legal arguments, it is precisely what needs to be established in order to determine responsibility. (What exactly was the actual cause of the car accident or the medical problem?) The philosophy literature has been struggling with the problem of defining causality since the days of Hume, in the 1700s. Many of the definitions have been couched in terms of counterfactuals. (C is a cause of E if, had C not happened, then E would not have happened.) In 2001, Judea Pearl and I introduced a new definition of actual cause, using Pearl's notion of structural equations to model counterfactuals. The definition has been revised twice since then, extended to deal with notions like "responsibility" and "blame", and applied in databases and program verification. I survey the last 15 years of work here, including joint work with Judea Pearl, Hana Chockler, and Chris Hitchcock. The talk will be completely self-contained.

第二次讲座

时间：2017年10月27日晚 7：00--9：00

地点：清华大学主楼327

讲座题目：Moral Responsibility, Blameworthiness, and Intention: In Search of Formal Definitions

主持人：万俊人（清华大学人文学院院长、教授）

摘要：The need for judging moral responsibility arises both in ethics and in law. In an era of autonomous vehicles and, more generally, autonomous AI agents, the issue has now become relevant to AI as well. Although hundreds of books and thousands of papers have been written on moral responsibility, blameworthiness, and intention, there is surprisingly little work on defining these notions formally. But we will need formal definitions in order for AI agents to apply these notions. In this talk, I take some preliminary steps towards defining these notions. This is joint work with Max Kleiman-Weiner.

第三次讲座

时间：2017年10月28日晚 7：00--9：00

地点：清华大学主楼327

讲座题目: Game Theory With Translucent Players

主持人：王巍（清华大学社科学院教授）

摘要：A traditional assumption in game theory is that players are opaque to one another---if a player changes strategies, then this change in strategies does not affect the choice of other players' strategies. In many situations this is an unrealistic assumption. We develop a framework for reasoning about games where the players may be translucent to one another; in particular, a player may believe that if she were to change strategies, then the other player would also change strategies.

I show that by assuming translucent players, we can recover many of the regularities observed in human behavior in well-studied games such as Prisoner's Dilemma, Traveler's Dilemma, Bertrand Competition, and the Public Goods game. I then consider solution concepts appropriate for translucent players. I characterize the analogues of rationalizability and Nash equilibrium for translucent players. The former is defined in terms of an analogue of common belief of rationality: Common Counterfactual Belief of Rationality (CCBR) holds if (1) everyone is rational, (2) everyone counterfactually believes that everyone that everyone else would still be rational even if $i$ were to switch strategies), (3) everyone counterfactually believes that everyone else is rational, and counterfactually believes that everyone else is rational, and so on.CCBR characterizes the set of strategies surviving iterated removal of minimax-dominated strategies, where a strategy s for player i is minimax dominated by s' if the worst-case payoff for i using s' is better than the best possible payoff using s.

This first part of the talk represents joint work with Valerio Capraro;

the second part represents joint work with Rafael Pass.

讲座组织： 清华大学-阿姆斯特丹大学逻辑学联合研究中心

清华大学人文学院哲学系