The space between reality and your dreams, which God will bridge in the final step. The space between your mind and your brother's, which is a mental space but is symbolized by separate bodies and the physical space between them. In this imagined gap arises the entire world, which is merely a collection of images projected on the fog that fills the gap. The gap is filled with countless idols and is the source of sickness. You try to join your brother by having your bodies meet in the gap. Yet real joining comes from acknowledging that the gap is completely empty and is not even there (see T-28.VI.5:4). See separation. See T-28.III.3-5, T-28.V.7, T-29.I.