Sound and music are perhaps the clearest illustration of the pattern I’m describing. Sounds exist quite literally within other sounds. A single note on the piano is “indwelt” by its overtones, and at the same time sounds through those overtones. Each tone of a chord provides a setting for every other, and in a melody line each note, like a word of a poem, falls silent to make room for the next””but that falling-silent lingers in the memory and air. When we sing, we form a community of sound, each voice singing the same song, soprano setting the context for bass even as bass frames soprano. When we sing, each singer sings through others, literally vibrating the flesh of her nearest neighbors. Music is perhaps our most elaborate, and most lovely, clue to the nature of the universe and the hopes of human society.
The classic doctrine of the Trinity illumines the world we live in, helping us to discover clues to the Trinitarian life within creation. Not only that, a perichoretic imagination of the world and human existence works itself out in truly Christian ethics. Others indwell our lives; therefore we ought to open our lives hospitably to them. We indwell the lives of others; therefore, we ought to see others not as obstacles to our plots and projects but as potential homes in which we can dwell together. A world of mutual interpenetration implies an ethic of hospitality, welcome, invitation, companionship, centered on a common table. The world created by our Triune God is a world organized by and for love.
And when we get to that point, Jesus’ prayer comes back into focus: Jesus calls us to be one even as the Father is in the Son and the Son is in the Father, to live as humans in a way that displays the very life of God.