[FOM] Strict identity relation and possible worlds

[Carlos Gonçalves]

Hi all,

Consider a set of possible worlds F and a binary relation E, such that 
(w,w') are in E if, and only if, they are the same element of F, E could 
thus be thought of as a strict identity relation between possible worlds. 
If the set F is such that there are no indescernible worlds, then E holds 
intuitively for this set, otherwise, if at least two worlds in F are 
indescernible, then we have that strict identity between worlds (as defined 
by E) and indescernibility between worlds do not coincide.

My questions are, as follows:

Are there any arguments that:

(1) Put into question E when no indescernible worlds are elements of F ?

(2) Put into question the argument that strict identity between worlds (as 
defined above in terms of E) and indescernibility between possible worlds 
do not coincide?

If you could shed some light on possible arguments, would greatly 
appreciate it.

Thanks,

C. Pedro