 Moreover, once we’ve seen the trick of generating non-doxastic similarity cases, it’s straightforward to generate non-doxastic difference cases as well. A wants to lead and B wants to follow. That’s a difference in preference, that gives rise to systematic differences in behavior. But it’s not a difference in traditional propositions desired. Very clearly, it’s not a difference in the possible worlds A and B favor—both favor the worlds in which A leads and B follows. And it’s not clear how the extra structure of traditional propositions that aren’t sets of worlds (e.g., Russellian propositions) could help draw the distinction. (Lewis discusses a similar case in “Dispositional Theories of Value”, 1989: 119.)