LIRa Session: Fausto Barbero

Speaker: Fausto Barbero (University of Helsinki)

Date and Time: Thursday, March 21st 2019, 16:30-18:00

Venue: ILLC Seminar Room F1.15, Science Park 107.

Title: Interventionist Counterfactuals in Team Semantics.

Abstract. Team semantics is a generalization of Tarskian semantics which allows the introduction of a greater variety of logical operators – most notably, atoms which express dependencies among variables. This extra degree of freedom is obtained by replacing the notion of satisfaction by an assignment with satisfaction by a set of assignments (“team”).

I will show how to enrich this framework so that a notion of intervention (in the spirit of structural equation modeling) can be applied to teams. After this move, it becomes possible to introduce interventionist counterfactuals over teams, and express a variety of notions of causal dependence in terms of them. I will consider a basic formalism which conservatively extends the usual languages of causal modelling, and some further operators.

Passing from teams to multiteams (multisets of assignments), we will see a way of introducing probabilities in the framework. It will emerge that some distinctions made in causal modelling, e.g. between “do expressions” and “counterfactual expressions”, can be explained in terms of commutation of simpler logical operators. .