  Intuitively, (1) and (3) are true while (2) and (4) are false. Moreover, someone who rejects intuitionism might well wish to argue against intuitionism by relying on something like (3), even though what the antecedent states is, by her lights, impossible. These facts have led some to suppose that (1) and (3) are not merely true, but non-trivially true (for more on these sorts of arguments, see the entry for Impossible Worlds). Vaihinger’s fictionalism might thus be read as adding a heap of substantive examples to the list of alleged non-trivial counterpossible conditionals.