(Update: There was unfortunately a mistake in the definition of optimal choices. This has been corrected now. [2019-07-01 Mon 22:31])
After having covered many of the essential aspects of modelling actions and choices of individual agents and groups of agents, we will now finally come to our central topic: normative reasoning. How can we, for instance, express that an agent ought to study?
Ought to be An idea that was successfully applied in the context of Standard Deontic Logic (SDL) was the idea to use the notion of deontically ideal worlds.

Last time we have learned about the \(\mathsf{cstit}\) operator for individual agents. Today we look at a variant which infuses a deliberative flavor into the operator, the so-called \(\mathsf{dstit}\). We will also develop a better understanding of the notion of refraining. Finally we will consider group actions.1
Deliberative stit For instance, one may demand that if an agent sees to it that \(A\) then there should have been at least the possibility that \(\neg A\) turns out to be true.

Time for another fun blog entry … and it is indeed finally time to cover time and when we’re already at it to throw some agency in it as well.
In our last session, Michael Kesselheim gave a very nice presentation on stit-logic based on John Horty’s splendid book from 2001. In what follows, I will capture the most important insights from this session (typos and mistakes in this post are my responsibility, not his!

In this session, Tim Forche gave an excellent presentation on the very interesting solution to the problem of Free Choice Permission based on truth-maker semantics proposed by Anglberger, Korbmacher and Faroldi in their DEON 2016 paper.
[Under construction.]

This will be an entry by Laura and Thomas. It is not finished yet.

In the last session Laura and Thomas presented McNamara’s account of supererogation, as presented in his 1996 article in Mind. In order to get a better grip on his semantic framework, we investigate some properties that may hold or may not hold in his system. Consider always first what your pre-analytic intuitions tell you about the property and decide for yourself whether the formal framework is useful to get a more precise understanding of the underlying concepts.

This session was mostly dedicated to exercises with the semantics of SDDL.

In this session we introduced Standard Dyadic Deontic Logic which utilizes a possible world semantics to make sense of conditional obligations, including contrary-to-duty cases. Exercises are included.

This entry contains solutions to the exercises from Session 3.

In our third session we shot the final bullet at SDL by showing that it leads to yet more problems with conditional obligations. This strongly motivates that deontic logic is a research program with its own characteristic problems that call for solutions that go beyond the canon of standard modal logics.