ILLC-LIRa May 2020

illc-lira@list.uva.nl

1 participants
10 discussions

LIRa session (online only): Chenwei Shi
by LIRa Seminar 27 May '20

27 May '20

Dear all, Tomorrow we will have our next LIRa session. Here is the zoom link: https://uva-live.zoom.us/j/92387951170?pwd=VHBNcElBdzdhS2dKSGd6NHRMRmZFQT09 (Meeting ID: 923 8795 1170, Password: 040025) You can find the details of the talk below and the guidelines for our online sessions here: https://projects.illc.uva.nl/lgc/seminar/guidelines-for-online-sessions/ Speaker: Chenwei Shi (Department of Philosophy, Tsinghua University, Beijing) Date and Time: Thursday, May 28th 2020, 16:30-18:00, Amsterdam time. Venue: online. Title: Logic of Convex Order (Joint work with Yang Sun) Abstract. Given a preference order on a set of possible worlds, there are different ways of extending/lifting it to a preference order on sets of worlds. For example, A >= B if and only if for all elements b in B there is an element a in A such that a >= b. This way of lifting order is usually named after Lewis, called l-lifting. In this talk, I will focus on another well-known way of order lifting, called \"Egli-Milner ordering\". Compared with the l-lifting, it only adds one more condition: for all elements a in A there is an element b in B such that a >= b. In this talk, I will examine the resulting logic of the Egli-Milner order. By presenting a sound and complete axiom system, I will show that the Egli-Milner order is \"convex\", which can be seen as a weaker form of monotonicity. To further illustrate the non-monotonicity of the Egli-Milner order, I will then discuss the relation between l-lifting, Egli-Milner order and conditional belief defined in a plausibility model. Hope to see you there! The LIRa team

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LIRa session (online only): Chenwei Shi
by LIRa Seminar 22 May '20

22 May '20

Dear all, We will have our next LIRa session on Thursday, May 28th. Our speaker is Chenwei Shi. You will receive the zoom link and a reminder of the guidelines for online sessions the day before the talk. After the talk, we will continue the discussion with (online) drinks, as usual. You can find the details below. Speaker: Chenwei Shi (Department of Philosophy, Tsinghua University, Beijing) Date and Time: Thursday, May 28th 2020, 16:30-18:00, Amsterdam time. Venue: online. Title: Logic of Convex Order (Joint work with Yang Sun) Abstract. Given a preference order on a set of possible worlds, there are different ways of extending/lifting it to a preference order on sets of worlds. For example, A >= B if and only if for all elements b in B there is an element a in A such that a >= b. This way of lifting order is usually named after Lewis, called l-lifting. In this talk, I will focus on another well-known way of order lifting, called \"Egli-Milner ordering\". Compared with the l-lifting, it only adds one more condition: for all elements a in A there is an element b in B such that a >= b. In this talk, I will examine the resulting logic of the Egli-Milner order. By presenting a sound and complete axiom system, I will show that the Egli-Milner order is \"convex\", which can be seen as a weaker form of monotonicity. To further illustrate the non-monotonicity of the Egli-Milner order, I will then discuss the relation between l-lifting, Egli-Milner order and conditional belief defined in a plausibility model. Hope to see you there! The LIRa team

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Social session cancelled!
by LIRa Seminar 21 May '20

21 May '20

Dear all, As several of you have decided to skip today\'s zoom social gathering in order to enjoy the summer weather in the Netherlands, we think it is better to cancel the meeting, so you can go out and enjoy the sun (while staying safe and keeping social distance!). The LIRa team

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LIRa drinks
by LIRa Seminar 21 May '20

21 May '20

Dear all, Here are the details for the social session later today: Topic: LIRa meeting Time: May 21, 2020 05:00 PM Amsterdam Join Zoom Meeting https://uva-live.zoom.us/j/92865256662 Meeting ID: 928 6525 6662 Hope to see you there! The LIRa team

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LIRa social session
by LIRa Seminar 15 May '20

15 May '20

Dear all, While next Thursday (May 21) is officially a day off, we are planning on having a casual LIRa drinks meeting at 17:00. As usual, you will receive the zoom invitation the day before. Hope to see you there! The LIRa team

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LIRa session (online only): NEW LINK!!
by LIRa Seminar 14 May '20

14 May '20

Dear all, Here is the new link for Alexandru Baltag\'s talk: Topic: LIRA NEW Time: May 14, 2020 04:35 PM Amsterdam, Berlin, Rome, Stockholm, Vienna Join Zoom Meeting https://uva-live.zoom.us/j/97371927698 Meeting ID: 973 7192 7698 The LIRa team

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LIRa session (online only): Alexandru Baltag
by LIRa Seminar 13 May '20

13 May '20

Dear all, Tomorrow we will have our next LIRa session. Here is the zoom link: https://uva-live.zoom.us/j/99721544628?pwd=Y3h3UklnOEpIdlEwTlAwWVFzRGl3Zz09 (Meeting ID: 997 2154 4628, Password: 759793). You can find the details of the talk below and the guidelines for our online sessions here: https://projects.illc.uva.nl/lgc/seminar/guidelines-for-online-sessions/ Speaker: Alexandru Baltag Date and Time: Thursday, May 14th 2020, 16:30-18:00, Amsterdam time. Venue: online. Title: From known correlations to the logic of continuous dependence Abstract. An empirical variable is one whose exact value might not be knowable, and instead only inexact approximations can be observed. Examples are in natural sciences, economics etc (where the inexact observations are some form of measurements), but also in the semantics of questions in natural language (where the inexact observations are partial answers). This leads to a topological conception of empirical variables, as maps from the state space into a topological space. Here, the exact value of the variable is represented by the output of the map, while the open neighborhoods of this value represent the knowable approximations of the exact answer. A central tenet in empirical sciences is establishing functional correlations between variables, with a view towards (1) establishing causality, but also (2) predicting the (approximate) value of a hard-to-measure variable Y when given (approximate) value(s) of easier-to-measure variable X. In interrogative terms, this is related to inquisitive implication: every partial answer to question Y is entailed by some partial answer to X. In this talk, I argue that knowability of a dependency amounts to the continuity of the given functional correlation. I give a learning-theoretic justification of this claim, connecting with Kevin Kelly\'s notion of gradual learnability, then I give some concrete examples. Next, I present a complete and decidable axiomatization of the logic of continuous dependence, and briefly skech the ideas behind the proofs. Further, I discuss the distinction between knowing the dependence between X and Y, and knowing how to determine Y (with any desired accuracy) from X: the later is a stronger notion of knowability, that requires the ability to find the accuracy that is needed for X-measurements (to determine Y with the given accuracy). I formalize this distinction in terms of continuity versus uniform continuity of the underlying dependence map, and go on to propose an axiomatization of strongly known dependence, in the framework of uniform spaces (-Andrè Weil\'s qualitative generalization of metric spaces). Time-permitting, I may go back to the problem of learning true causal relations from observed functional correlations. I will end with a number of open questions, some technical and some conceptual. This is ongoing joint work with Johan van Benthem, embodied in a follow-up draft to our joint work on the Logic of Functional Dependence, presented at a previous LIRa seminar. (But my presentation will be self-contained.) Hope to see you there! The LIRa team

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LIRa session (online only): Alexandru Baltag
by LIRa Seminar 10 May '20

10 May '20

Dear all, We will have our next LIRa session on Thursday, May 14th. Our speaker is Alexandru Baltag. You will receive the zoom link and a reminder of the guidelines for online sessions the day before the talk. After the talk, we will continue the discussion with (online) drinks, as usual. You can find the details below. Speaker: Alexandru Baltag Date and Time: Thursday, May 14th 2020, 16:30-18:00, Amsterdam time. Venue: online. Title: From known correlations to the logic of continuous dependence Abstract. An empirical variable is one whose exact value might not be knowable, and instead only inexact approximations can be observed. Examples are in natural sciences, economics etc (where the inexact observations are some form of measurements), but also in the semantics of questions in natural language (where the inexact observations are partial answers). This leads to a topological conception of empirical variables, as maps from the state space into a topological space. Here, the exact value of the variable is represented by the output of the map, while the open neighborhoods of this value represent the knowable approximations of the exact answer. A central tenet in empirical sciences is establishing functional correlations between variables, with a view towards (1) establishing causality, but also (2) predicting the (approximate) value of a hard-to-measure variable Y when given (approximate) value(s) of easier-to-measure variable X. In interrogative terms, this is related to inquisitive implication: every partial answer to question Y is entailed by some partial answer to X. In this talk, I argue that knowability of a dependency amounts to the continuity of the given functional correlation. I give a learning-theoretic justification of this claim, connecting with Kevin Kelly\'s notion of gradual learnability, then I give some concrete examples. Next, I present a complete and decidable axiomatization of the logic of continuous dependence, and briefly skech the ideas behind the proofs. Further, I discuss the distinction between knowing the dependence between X and Y, and knowing how to determine Y (with any desired accuracy) from X: the later is a stronger notion of knowability, that requires the ability to find the accuracy that is needed for X-measurements (to determine Y with the given accuracy). I formalize this distinction in terms of continuity versus uniform continuity of the underlying dependence map, and go on to propose an axiomatization of strongly known dependence, in the framework of uniform spaces (-Andrè Weil\'s qualitative generalization of metric spaces). Time-permitting, I may go back to the problem of learning true causal relations from observed functional correlations. I will end with a number of open questions, some technical and some conceptual. This is ongoing joint work with Johan van Benthem, embodied in a follow-up draft to our joint work on the Logic of Functional Dependence, presented at a previous LIRa seminar. (But my presentation will be self-contained.) Hope to see you there! The LIRa team

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LIRa session (online only): Anthia Solaki
by LIRa Seminar 06 May '20

06 May '20

Dear all, Tomorrow we will have our next LIRa session. Here is the zoom link: https://uva-live.zoom.us/j/92163487348?pwd=cDluVzZxN2hlNVAzZnI1SDdJcU9Bdz09 (Meeting ID: 921 6348 7348, Password: 040025). The details of the talk are below. You can find the guidelines for our online sessions here: https://projects.illc.uva.nl/lgc/seminar/guidelines-for-online-sessions/ Speaker: Anthia Solaki Date and Time: Thursday, May 7th 2020, 16:30-18:00, Amsterdam time. Venue: online Title: A logical formalisation of False Belief Tasks (joint work with Fernando Velázquez-Quesada) Abstract. Theory of Mind, the cognitive capacity to attribute internal mental states to oneself and others, is a crucial component of social skills. Its formal study has become important, witness recent research on reasoning and information update by intelligent agents, and some proposals for its formal modelling have put forward settings based on Epistemic Logic (EL). Still, due to intrinsic idealisations, it is questionable whether EL can be used to model the high-order cognition of \"real\" agents. We propose a mental attribution modelling logical framework based on agents\' temporal visibility, that is more in-line with findings in cognitive science and suitable to model well-known False-Belief tasks. We discuss some of its technical features and argue on why it does justice to empirical observations. We finally extend the temporal visibility models to capture that communication (next to observation) comes into play when attributing beliefs to others. We illustrate the workings of the new system in the modelling of more complicated False-Belief tasks. Hope to see you there! The LIRa team

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LIRa session (online only): Anthia Solaki
by LIRa Seminar 01 May '20

01 May '20

Dear all, We will have our next LIRa session on Thursday, May 7th. Our speaker is Anthia Solaki. You will receive the zoom link and a reminder of the guidelines for online sessions the day before the talk. After the talk, we will continue the discussion with (online) drinks, as usual. Please, find the details below. Speaker: Anthia Solaki Date and Time: Thursday, May 7th 2020, 16:30-18:00, Amsterdam time. Venue: online Title: A logical formalisation of False Belief Tasks (joint work with Fernando Velázquez-Quesada) Abstract. Theory of Mind, the cognitive capacity to attribute internal mental states to oneself and others, is a crucial component of social skills. Its formal study has become important, witness recent research on reasoning and information update by intelligent agents, and some proposals for its formal modelling have put forward settings based on Epistemic Logic (EL). Still, due to intrinsic idealisations, it is questionable whether EL can be used to model the high-order cognition of \"real\" agents. We propose a mental attribution modelling logical framework based on agents\' temporal visibility, that is more in-line with findings in cognitive science and suitable to model well-known False-Belief tasks. We discuss some of its technical features and argue on why it does justice to empirical observations. We finally extend the temporal visibility models to capture that communication (next to observation) comes into play when attributing beliefs to others. We illustrate the workings of the new system in the modelling of more complicated False-Belief tasks. Hope to see you there! The LIRa team

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ILLC-LIRa May 2020