x1 (abstraction) should/(of right) ought to be true/happening under conditions/in the case of x2 being true/happening, as believed by/by standard/under consideration of x3. If the world were proper/correct/just/ruled perfectly and strictly according to x3 and if x2 were true, then x1 would be true as well.
x1 is reality / "the real world" ("this" world, the world the speaker and [presumably] listener reside in), containing/defining x2 (objects and facts) defined by rules x3