The slogan that a related concept involves “the appearance of” this property is presented in a Stephen Yablo paper that discusses an “establish’d maxim in metaphysics” given by David Hume. Quine argued against a type of entity named for this property by imagining a fat man and a bald man, both with this property, in the same (10[1])doorway. Alvin Plantinga’s version of the ontological argument uses the premise that this property applies to the proposition “there is a being that has maximal greatness.” In the most common interpretation, this property is represented by the diamond operator introduced by C. I. Lewis. A paper asking whether conceivability entails this property was written by David Chalmers, who argued that philosophical zombies have the “logical” type of this property. For 10 points, in modal logic, formulas are true or false relative to what type of “world”? ■END■