The zero is not assumed, but objective: the state of things before the negotiation.
If before the negotiation, a landslide was already closing on your (uninsured) country house, then after the negotiation the “state of things” is going towards the negative, for reasons unrelated to the negotiation. The question here is about the supposed distinction between that landslide and your opponent’s decision algorithm.
If before the negotiation, a landslide was already closing on your (uninsured) country house, then after the negotiation the “state of things” is going towards the negative, for reasons unrelated to the negotiation. The question here is about the supposed distinction between that landslide and your opponent’s decision algorithm.
I can’t find the example this is from.