 Sometimes there is an explanation of why weak supervenience holds despite the fact that strong supervenience does not. If, within a world, two individuals assert exactly the same propositions, then they are exactly alike vis-à-vis having asserted a true proposition: the one asserted at least one true proposition if and only if the other did. The reason is that a proposition will have a unique truth-value relative to a world. The following weak supervenience thesis thus holds: for any world w, and any individuals x and y in w, if x and y are indiscernible with respect to what propositions they have asserted, then they are indiscernible with respect to having asserted a true proposition. Contingent propositions, however, are true in some worlds and false in others. It is thus possible for two individuals in different worlds to assert exactly the same propositions, and yet differ with respect to having asserted a true proposition. The one might assert many true propositions, while the other fails to assert any true proposition. It follows that the following strong supervenience thesis is false: for any worlds w1 and w2, any individuals x in w1 and y in w2, if x in w1 is indiscernible from y in w2, with respect to what propositions they have asserted, then x in w1 is indiscernible from y in w2 with respect to having asserted a true proposition.