 Fictionalism: Like ideal gases or frictionless surfaces, possible states of affairs are (useful) fictions; only facts exist. Assume that a is not F. There exists no possible state of affairs a’s being F. But there is the fiction of possible states of affairs according to which there is the state of affairs a’s being F if, and only if, a and being F are contained in some facts (see Armstrong 1989: 46 and 49ff and the entry on  modal fictionalism  for a detailed overview).