Tsinghua Logic Salon

Initiated by the center’s students and researchers in 2019, the Tsinghua Logic Salon has quickly grown into a lively platform for try-outs and exchanges of new ideas. Researchers in various fields of logic are invited to present their latest research, as well as the challenges that they see. Every participant is encouraged to engage in discussions and exchange of perspectives. Each session lasts for 1.5 hours in total, with 30 minutes of discussion included.

Organizing Committee (from September 2021): Junhua Yu, Chenwei Shi, Yinlin Guan, Yiyan Wang, Jialiang Yan, Penghao Du.

■Schedule for 2022-2023 academic year

2023 Feb 23 Sonja Smets (University of Amsterdam)
2023 Mar 02Dun Deng 邓盾 (Tsinghua University)
2023 Mar 09Fan Yang 杨帆 (Utrecht University)
2023 Mar 16Feng Ye 叶峰 (Capital Normal University)
2023 Mar 23Xinwen Liu 刘新文 (Chinese Academy of Social Sciences)
2023 Mar 30Frederik van der Putte (Ghent Unibersity)
2023 Apr 06Fengkui Ju 琚凤魁 (Beijing Normal University)
2023 Apr 20Shengyang Zhong 钟盛阳(Peking University)
2023 May 13Wes Holliday (University of California, Berkeley)
2023 May 18Fei Liang 梁飞 (Shandong University)
2023 May 25Marta Bilkova (Czech Academy of Sciences)
2023 Jun 01Yan Zhang 张炎 (Renmin University of China)
2023 Jun 08Hao TANG 唐浩 (Tsinghua University)

■Current Events

2023 Mar 30 16:00~17:30 Frederik van der Putte (Ghent University) The problem of no hands : responsibility voids in collective decisions

The problem of no hands concerns the existence of so-called responsibility voids: cases where a group makes a certain decision, yet no individual member of the group can be held responsible for this decision. Criteria-based collective decision procedures play a central role in philosophical debates on responsibility voids. In particular, the well-known discursive dilemma has been used to argue for the existence of these voids. But there is no consensus: others argue that no such voids exist in the discursive dilemma under the assumption that casting an untruthful opinion is eligible. We argue that, under this assumption, the procedure used in the discursive dilemma is indeed immune to responsibility voids, yet such voids can still arise for other criteria-based procedures. We provide two general characterizations of the conditions under which criteria-based collective decision procedures are immune to these voids. Our general characterizations are used to prove that responsibility voids are ruled out by criteria-based procedures involving an atomistic or monotonic decision function. In addition, we show that our results imply various other insights concerning the logic of responsibility voids.

Reference available at https://biblio.ugent.be/publication/8735886

2023 Mar 23 16:00~17:30 Xinwen Liu 刘新文 (Chinese Academy of Social Sciences) 金岳霖对“刘易斯-海德格尔”问题的回答


2023 Mar 16 16:00~17:30 Feng Ye 叶峰 (Capital Normal University) Introducing Studies in No-Self Physicalism

This talk will introduce my recent book Studies in No-Self Physicalism. I will first explain the basic ideas of ‘no-Self’ physicalism. This introduces the basic assumptions and overall goal of the researches presented in this book and introduces chapters 1 and 2 of the book. Chapters 3 to 8 of the book develop a series of philosophical theories under the framework of No-Self Physicalism. They include theories on concept and conceptual representation (Chapter 3), thought, truth, analyticity, belief ascription, and modality (Chapter 4), philosophy of mathematics (Chapter 5), epistemic justification, knowledge, apriority, and intuition (Chapter 6), physicalistic ontology (Chapter 7), and coherent formulation of physicalism (Chapter 8). This talk will also very briefly introduce some of the ideas in these chapters.
Speaker’s homepage – http://cnu-cn.academia.edu/FengYe

2023 Mar 09 16:00~17:30 Fan Yang 杨帆 (Utrecht University) Dependence logic and its axiomatization problem

Dependence logic was introduced by Väänänen (2007) as a novel formalism for reasoning about dependence and independence relations. The logic adopts the team semantics of Hodges (1997). The basic idea of team semantics is that dependency properties can only manifest themselves in multitudes, and thus formulas of dependence logic are evaluated on sets of assignments (called teams) instead of single assignment as in the usual Tarskian semantics. A team can be naturally viewed as a relational database, a dataset, an information state, etc. Thanks to the simple structure of teams and the abundance of their interpretations in various fields of science, team semantics and dependence logic have recently found a number of applications in addressing issues in database theory, formal linguistics, quantum foundations, social choice and so on. In the first part of this talk, I will provide an overview of the core theory and applications of dependence logic. Teams are essentially relations, which are second-order objects. Dependence logic is known to be equivalent to existential second-order logic, and thus cannot be effectively axiomatized in full. In the second part of the talk, I will survey some recent developments in finding partial axiomatizations for dependence logic.

Speaker’s homepage: https://sites.google.com/site/fanyanghp/

2023 Mar 02nd 16:00~17:30 Dun Deng (邓盾,Tsinghua University) Internal antisymmetry of Chinese disyllabic coordinative verbs and its theoretical implications

In this talk, I will first demonstrate the internal antisymmetry of Chinese disyllabic coordinative verbs (CDCVs) such as \zhi-zao/ ‘manufacture’ and \xiu-li/ ‘repair’. Using a sample of 400 CDCVs and a carefully designed annotation scheme to analyze all the CDCVs, we find that for each of the 400 CDCVs, one of the two root morphemes inside the compound verb can be identified as the more prominent one (call it H), which plays a more important role than the other root morpheme in determining the argument structure of the compound verb. This means that the 400 CDCVs have an asymmetrical internal structure with its two root morphemes being unequal in function. By studying the properties of all the Hs, we find strategies employed by the grammar to decide H, and provide an account for the strategies. Relying on our empirical findings about the internal antisymmetry of CDCVs, I then discuss and try to explain two theoretical issues. The first is about a well-known generalization in Chinese linguistics, namely that disyllabic verbs exhibit nominal behavior which corresponding monosyllabic verbs lack. The other is about the peculiar fact that CDCVs exist in large amount in Chinese whereas other languages like English rarely have equivalents.

2023 Feb 23rd 19:00~20:30 Sonja Smets (University of Amsterdam) Learning what Others Know

I will present joint work with A. Baltag on modelling scenarios in which agents read or communicate (or somehow gain access to) all the information stored at specific sources, or possessed by some other agents (including information of a non-propositional nature, such as data, passwords etc). Modelling such scenarios requires us to extend the framework of epistemic logics to one in which we abstract away from the specific announcement and formalize directly the action of sharing ‘all you know’ (with some or all of the other agents). In order to do this, we introduce a general framework for such informational events, that subsumes actions such as ‘sharing all you know’ with a group or individual, giving one access to some folder or database, hacking a database without the owner’s knowledge, etc. We formalize their effect, i.e. the state of affairs in which one agent (or group of agents) has ‘epistemic superiority’ over another agent (or group). Concretely, we express epistemic superiority using comparative epistemic assertions between individuals and groups (as such extending the comparison-types considered in [5]). Another ingredient is a new modal operator for ‘common distributed knowledge’, that combines features of both common knowledge and distributed knowledge, and characterizes situations in which common knowledge can be gained in a larger group of agents (formed of a number of subgroups) by communication only within each of the subgroups. We position this work in the context of other known work such as: the problem of converting distributed knowledge into common knowledge via acts of sharing [4]; the more semantic approach in [2] on communication protocols requiring agents to ‘tell everybody all they know’; the work on public sharing events with a version of common distributed knowledge in [3]; and the work on resolution actions in [6].

[1] A. Baltag and S. Smets, Learning what others know, in L. Kovacs and E. Albert (eds.), LPAR23 proceedings of the International Conference on Logic for Programming, AI and Reasoning, EPiC Series in Computing, 73:90-110, 2020. https://doi.org/10.29007/plm4
[2] A. Baltag and S. Smets, Protocols for Belief Merge: Reaching Agreement via Communication, Logic Journal of the IGPL, 21(3):468-487, 2013. https://doi.org/10.1093/jigpal/jzs049
[3] A. Baltag, What is DEL good for? Lecture at the ESSLLI2010-Workshop on Logic, Rationality and Intelligent Interaction, 16 August 2010.
[4] J. van Benthem, One is a lonely number. In P. Koepke Z. Chatzidakis and W. Pohlers, (eds.) Logic Colloquium 2002, 96-129, ASL and A.K. Peters, Wellesley MA, 2002.
[5] H. van Ditmarsch, W. van der Hoek & B. Kooi, Knowing More – from Global to Local Correspondence, Proc. of IJCAI-09, 955–960, 2009.
[6] T. Agotnes and Y.N. Wang, Resolving Distributed Knowledge, Artificial Intelligence, 252: 1–21, 2017. https://doi.org/10.1016/j.artint.2017.07.002

■Past Events

Click HERE to check the past events.