McCarthy variations in a modal key

We take a fresh look at some major strands in John McCarthy's work from a logician's perspective. First, we re-analyze circumscription in dynamic logics of belief change under hard and soft information. Next, we re-analyze the regression method in the Situation Calculus in terms of update axioms for dynamic–epistemic temporal logics. Finally, we draw some general methodological comparisons between ‘Logical AI’ and practices in modal logic, pointing at some creative tensions.