Or could it, also, mean (in some contexts, at least) "Should A be this, B would be that" (which is called "future less vivid conditional" in Ancient Greek). I'm asking this because the two published English translations of a sentence that interests me, which begins with
Sollte die Ewigkeit etwas anderes sein als das leere Immersein,...
render it as "If eternity were something other than...", i.e., as counter-factual. I'm wondering whether this is the only possible interpretation.
The quote is from Heideggers talk Begriff der Zeit, see Google Books.