[lmm]

> I have to agree with you on locality in pure state machine, but if a state machine is defined as an Actor you get locality by definition.

Not really. You have a kind of binary version of locality - whether something is in the same actor or not - but you can't reason about any region that's smaller or larger than that. Incoming messages might arrive from anywhere, and emitted messages might cause any kind of effect anywhere (including other messages back to the sending actor). So you can't really understand any region larger than an actor without having to understand the whole system - and that's before we even get to passing actor addresses around.