 Here is an example to illustrate the distinctions. Suppose we view an information state as a pair of a finite set of discourse referents and a set of world/assignment pairs, where the assignments have as domain the given finite set of discourse referents. Such a state would be a context-in-the-first-sense and the set of discourse referents would be a context-in-the-second-sense. One basic kind of update would be update of content: here we constrain the set of world/assignment pairs, and leave the set of referents constant. A second basic kind of update would be extension of the set of referents: we extend our allocated storage capacity. We modify the given world/assignments pairs to pairs of worlds and extended assignments, where our extended assignments are constrained by the old ones, but take all possible values on the new referents. Thus, the update process in our example is two-dimensional: we have both update of content and update of context-in-the-second-sense.