 (2) A second difficulty noted by Fodor is that, like conceptual role semantics, the mapping conception may not deserve to be called “content,” because the narrow contents it yields do not suffice to determine truth conditions. A central characteristic of broad content is that a thought or belief with broad content thereby has truth conditions: in some possible circumstances it is true, and in others it is false. On the mapping conception, narrow content does not suffice to determine truth conditions in this sense. To determine truth conditions, one needs to fix not only a narrow content but also a context. For instance, given the narrow content shared by Oscar and Twin Oscar when they think, “Lake Superior is full of water,” we do not have enough information to say whether that thought is true or false in a particular situation. Suppose Lake Superior is full of XYZ. Then Twin Oscar’s thought is true but Oscar’s thought is false, even though both thoughts have the same narrow content. So it seems that narrow content by itself is not enough to determine what truth conditions a thought has. (However, see the following section on “Diagonal Propositions.”)