To replace a thing with something else. The separation began when the ego substituted its will for God’s Will, illusion for reality, fear for love. This ancient substitution is reflected now in our special relationships, in which we substitute one person for another. We do not realize just how alien this is to God, Who never chooses one person in place of another. In all our relationships, we seek not love, but rather the magical substitute for love (see T-23.II.12). However, the substitute for love is war, and that is exactly what we find. In the end, our substitutes never satisfy, for, quite simply, “there is no substitute for Heaven” (W-pI.182.3:6; the phrase “there is no substitute” occurs five times in the Course). Our substitutes not only do not satisfy, they have no reality, for we cannot truly replace what God created. We must acknowledge this, and follow the Holy Spirit as He seeks to reverse our substitution process. He would substitute forgiveness for our condemnation, the real world for our world, Christ’s vision for our perception, and the realization of our true Self for our self-concept. Yet on the road back, we must be careful not substitute the Holy Spirit’s gifts with the ego’s replacements for them, for that would merely be to repeat the original substitution “that shattered Heaven” (T-18.I.12:2).