As a teacher of God (and we're all God's teachers) how do you explain or otherwise work around observed phenomena that the course says don't exist and aren't real, without also referencing or implying a duality? For example, the ACIM concepts of real and unreal are themselves a duality applied as a teaching and communication tool. Teacher and student are also Course terms that exist as polarities. Is duality the forbidden fruit of ACIM or is it just a symbollic (conceptual) framework and useful communication tool?