Full Idea
The truth-grounds of '¬A' are precisely those possibilities that are incompatible with any truth-ground of A.
Gist of Idea
The truth grounds for 'not A' are the possibilities incompatible with truth grounds for A
Source
Ian Rumfitt (The Boundary Stones of Thought [2015], 7.1)
Book Reference
Rumfitt,Ian: 'The Boundary Stones of Thought' [OUP 2015], p.185
A Reaction
This is Rumfitt's proposal for the semantics of 'not', based on the central idea of a possibility, rather than a possible world. The incompatibility tracks back to an absence of shared grounding.
Related Idea
Idea 18828 If two possibilities can't share a determiner, they are incompatible [Rumfitt]