Editing Subjunctive possibility (section)

=== Epistemic possibility ===
The contrast with epistemic possibility is especially important to draw, since in ordinary language the same phrases ("it's possible," "it can't be", "it must be") are often used to express either sort of possibility. But they are not the same. We do not ''know'' whether [[Goldbach's conjecture]] is true or not (no-one has come up with a proof yet); so it is (epistemically) ''possible that'' it is true and it is (epistemically) ''possible that'' it is false. But if it ''is'', in fact, provably true (as it may be, for all we know), then it would have to be (subjunctively) ''necessarily'' true; what being provable ''means'' is that it would not be (logically) ''possible for'' it to be false. Similarly, it might not be at all (epistemically) ''possible that'' it is raining outside—we might ''know'' beyond a shadow of a doubt that it is not—but that would hardly mean that it is (subjunctively) ''impossible for'' it to rain outside. This point is also made by [[Norman Swartz]] and Raymond Bradley.<ref>Norman Swartz and Raymond Bradley, ''Possible Worlds — An Introduction to logic and its philosophy'', 1979, Hackett Publishing company, inc., {{ISBN|0-631-16130-9}}. pp. 329–330</ref>