Possibility

status of propositions that are neither always true nor always false

in philosophy, a complete and consistent way the world is or could have been

metaphysical question

something that is logically possible to occur

possibility considered in a counterfactual

mathematical theory for dealing with certain types of uncertainty and is an alternative to probability theory

result demonstrating that a particular problem cannot be solved as described in the claim, or that a particular set of problems cannot be solved in general