An empty room in a dream often reflects potential more than lack -- space that hasn't been filled yet, waiting for a decision about what belongs there. It can also point to loneliness, depending on how the room feels: still and hopeful, or hollow and unsettling. The emotional tone usually matters more than the emptiness itself.
We ought not to use arguments or tedious discourses in giving judgement, much less flatteries, but only to pronounce what is known by experience and firm reason. - Cardan Girolamo (1501-1576)