Just reading your comment I was thinking about the closed world assumption in logic (prolog), perhaps there are some middle concept between the Proof by Contradiction and the closed world assumption. In the real world we learn concepts (think about relativity or a non planar world) and then the old question is no longer a two value alternative.
Perhaps something like: In this field a new conception could appear that would invalidate what we consider today to be only two alternatives. Is not about many worlds reality or quantum computation, (3 minutes thinking time out).
Perhaps something like: In this field a new conception could appear that would invalidate what we consider today to be only two alternatives. Is not about many worlds reality or quantum computation, (3 minutes thinking time out).