|Impossible World: possible worlds are determined by counterfactual descriptions, specifying conditions for the existence of objects or laws, or a listing of instanced properties. The existence of an impossible world is already excluded by the concept. However, an impossible world can e.g. be characterized by the fact that in it all propositions are true. Then, for an arbitrary sentence A applies A is true and non-A is true. Thus, existence is excluded for every object and property. See also possible worlds, modal logic, necessity, possibility, possible world semantics._____________Annotation: The above characterizations of concepts are neither definitions nor exhausting presentations of problems related to them. Instead, they are intended to give a short introduction to the contributions below. – Lexicon of Arguments. |
Impossible World/imposs.w./Stalnaker/Cresswell: Problem: the concept of possibility is itself defined in terms of possible worlds. - Then impossible worlds permit merely an extra-strong concept of impossibility: truth in no world.
Problem: then a logically impossible proposition can never be true.
Contradiction: then there can only be as many propositions as possible worlds. - But there must be at the same time as many prepositions as sets of possible worlds. - ((s) All, only if one accepts them as basic concepts or primitive entities).
_____________Explanation of symbols: Roman numerals indicate the source, arabic numerals indicate the page number. The corresponding books are indicated on the right hand side. ((s)…): Comment by the sender of the contribution.
M. J. Cresswell
Semantical Essays (Possible worlds and their rivals) Dordrecht Boston 1988
M. J. Cresswell
Structured Meanings Cambridge Mass. 1984