"The teacher's own history is a conjunction of, on his mother's side, the farmers turned brewery-owning Atkinsons who rationally drained and reclaimed the land and, on his father's side, the lock keeping Cricks with their collection of fold myths and superstitions." My psychiatrist told me I was the clash of my mother's and father's opposite personalities inside myself, so Tom Crick, being the clash of beer and water, is mentally uneasy. Half of his heritage are land people, half water people.
The land people are part Here and Now. They work the fens, the land, the vacant reality. They manufacture beer, an escape from thought. They drain the land, trying to bring back the land. The land, Swift says, represents what hurts, the blank reality. The land is the Here and Now because alone it contains no stories or history.
The water people work with superstition. Water is connected to stories, less hearty or tangible than beer and land; water is not solid or empty; it is gliding, eroding flat land. The watrer may represent History; both water and history erode the land/the flat reality; they are intangible, inevitable, inevitable, natural, and mysterious.
Tom has to deal with the Here and Now (he will be fired), and his passion, history. His dilemmas, like all matter, he would argue, came from what came before them and before him, a family history, half concerned with solids, half liquid.