Vagueness is very useful. The answer I find is to flip your
   approach. Lessons learned from studying
   https://en.wikipedia.org/wiki/Apophatic_theology in my late 20s
   in the Eastern Orthodox Church (no longer a part of it) was very
   helpful. Another equivalent example is drawing a picture using
   negative space. Turn the air into something and make the subject
   air. In short, if you want to help improve your OWN
   understanding of someone who is vague, help them define what
   they're NOT and not define what they ARE. By cutting away, akin
   to a sculpture of clay vs a tower of Legos, what's left over is
   what's necessary. I'll give you a hint on how to start with
   vagueness: STEP ONE: There is the Universe. STEP TWO: What parts
   of the Universe are not included? That's one way but there's
   others.