Towers of Agency

There is basically one reason to build a tower, and that’s access: There is something that is available higher up that is not available on the ground. Most commonly, that thing is either “empty space” or “information transmission”. A skyscraper can access more space than a shorter building, and so it fits more real estate in a smaller footprint. A watchtower can access strategic information from the land below; a church steeple is tall enough for the sound of the bells to travel far through the air. Many of the tallest structures in the world maximize line-of-sight for radio transmissions. Imagine a stone or brick tower of your favorite type - one whose purpose is to access something high up. Or, if you prefer a specific suggestion, imagine the brick steeple of Old North Church in Boston, which held the signaling lanterns for Paul Revere. Consider some unremarkable block in the tower: On either side of this block are other blocks. Sitting on top of this block are more blocks. Below, holding our block’s weight: more blocks. One can ask, about the block we’ve chosen, the question “how?”: How is it that this block is at this spot? And the answer to that question is, locally, that it is held up by other blocks immediately below. Those blocks depend on others below them, and so indirectly our block is here by the grace of the whole set of blocks transitively beneath it. One can ask, about the block we’ve chosen, the question “why?”: For what purpose is this block at this spot? And the answer to that question is, locally, that it is holding up other blocks immediately above. Those blocks are holding up others above them, and so indirectly our block is here in order to help hold up the whole set of blocks transitively above it. “How are you going to put a stone there in that empty space?” asks Alice. “By first putting stones in the empty space beneath it.” replies Bob. “Why are you laying that brick?” asks Alice. “I want to rest this other brick on top of it.” replies Bob.