Every spring, two farmers meet to walk the length of a stone wall, hoisting fallen stones and small boulders back into place. Every winter, something -- "Something there is that doesn't love a wall, / That wants it down." -- brings part of the wall down again. The narrator recounts a Sisyphean task. Toward the end of the poem, he also alludes to a more ancient tradition and dark ritual when he describes seeing his neighbor as a remnant of an age when walls were ceremoniously built and consecrated with blood sacrifice: "I see him there, / Bringing a stone grasped firmly by the top / In each hand, like an old-stone savage armed. / He moves in darkness as it seems to me ...." The slightly ominous observation and the playful queries about why anyone would bother to rebuild an unnecessary wall contrast with the stoic reply of a neighbor who steadfastly embraces the way things have always been.
The narrator initiates the wall building each year, but he also questions its necessity. "My apple trees will never get across / And eat the cones under his pines," he says, and he then points out there are no cows to fence in. He realizes there is no practical reason for maintaining the barriers his neighbor blindly accepts, and that the land beneath the wall is one stretch of frozen ground that heaves and dismantles the stones each winter. The larger question here is which is more important: the advantage of community or the carefully maintained separations that connect neighbors only each year and only for the process of reinforcing boundaries. The neighbor asserts that a good fence keeps the rest of the world safely at bay with minimal complication. The narrator pokes at the hand-me-down aphorism, “Good fences make good neighbors,” but still celebrates the annual ritual of wall-building with his taciturn neighbor.
The novelist Graham Greene once remarked to Robert Frost that he found the line "good fences make good neighbors" puzzling. Frost replied, "I wish you knew more about it, without my helping you." Frost never explained his poems, but he often repeated that describing what he had written in "less good words" took all the fun out of the encounter. He left it to readers to figure things out, and scattered clues to meaning while simultaneously drawing veils over it at different turns. On its face, "Mending Walls" provides a simple account of an annual spring farm ritual in which neighbors rebuild the walls between their farms that tumbled during the winter. Frost, however, imbues his words with so much meaning that the poem is an allegory; the characters and their situations symbolize the enigma of what it means to be human.
Frost plays with everything: the ideas in his poem, the sounds of the words he chooses, and the meanings of the words themselves. "Something there is that doesn't love a wall, / That sends the frozen-ground-swell under it ...." Since a frozen groundswell is another phrase for a frost, is the poet himself the "something" that doesn't love the wall? Is the poem an exploration of community versus isolation? Frost doesn't say, but he continues to tease and play with language and ideas throughout. "Before I built a wall I'd ask to know / What I was walling in or walling out, / And to whom I was like to give offense." "Offense" sounds like "a fence," hardly an accident from a poet so precise. The words distinctly belong to Frost and the age in which he lived, but they are so right and so simple that "Mending Wall" speaks to readers as if it were written yesterday and not a century ago.