 Again, PAC is the dynamic logic of hard information. The epistemic logics dealing with soft information fall within the scope of belief revision theory (van Benthem 2004; Segerberg 1998). Recall that hard and soft information are not distinct types of information per se, rather they are distinct types of information storage. Hard-stored information is unrevisable, whereas soft-stored information is revisable. Variants of PAL that model soft information augment their models with plausibility-orderings on information-states (Baltag and Smets 2008). These orderings are known as preferential models in non-monotonic logic and belief-revision theory. The logics can be made dynamic in virtue of the orderings changing in the face of new information (which is the mark of soft information as opposed to hard information). Such plausibility-orderings may be modelled qualitatively via partial orders etc., or modelled quantitatively via probability-measures. Such quantitative measures provide a connection to a broader family of quantitative approaches to semantic information that we will examine below. Recent work by Allo (2017) ties the soft information of dynamic epistemic logic to non-monotonic logics. This is an intuitive move. Soft information is information that has been stored in a revisable way, hence the revisable nature of conclusions in non-monotonic arguments makes non-monotonic logics a natural fit. On this very topic, see also Chapter 13.7 of van Benthem (2011). 