Eight lines, four couplets, no capital letters and not one full stop: "Cog" is laid out like something said under the breath. Its subject is a modest but stubborn question. What do you do with a life when the big prizes, truth above all, are out of reach? The speaker's answer is not a philosophy or a plan. It is a confession, made almost sheepishly, that he walks in the fields to sing.
The opening couplet is the bleakest and the strangest. "truth is the thing I cannot have" is flat and absolute, and the verb "have" turns truth into an object, something that might be owned or carried home. Then comes "melancholy as a desert," a fragment with no verb. We are not told whether melancholy is like a desert or simply is one, and the gap is part of the effect: the sentence never arrives anywhere, just as a desert doesn't. "Melancholy" is also the longest word in the poem, four syllables stretched across the line. Everything after it is plainer and shorter.
The title enters in the second couplet. "I go to work / well enough" gives us a life with no complaint and no description of the job, only attendance. A cog is a small toothed part in a larger machine, and that is how the speaker sounds here: turning, doing his bit. The line break leaves "well enough" stranded on its own, and it can be read two ways. He manages fine, or he manages only just. The deadpan tone refuses to say which. "Cog" also has an older sense, to cheat at dice. If that echo is intended, it would sit uncomfortably beside the first line, with a word for trickery hovering near the thing the speaker cannot have.
The third couplet turns to ambition, and disclaims it. "I do not desire to write a book" is a predictable modesty, but "or live in one" is the surprise. To live in a book would be to live inside a finished story, one with a shape, a point and a neat meaning. That is exactly what the speaker's days lack. He turns down the consolation of fiction as firmly as he accepts that truth is closed to him. There is a quiet irony too, since the refusal is made inside a poem, a piece of writing small enough to be the opposite of a book.
Then the poem swings on its smallest word: "but I must confess I walk / in the fields to sing." "Confess" borrows the language of guilt and religion for something harmless, even lovely, and the speaker seems faintly embarrassed to admit it. The imagery answers the desert directly, with fields in place of dryness. The verbs shift too. "Cannot have" belongs to possession, while "walk" and "sing" are things you do, and they need nothing owned. The line break after "walk" gives the reader a pause, almost a step. The final line, "in the fields to sing," is five single-syllable words, as plain as footfalls. Singing is also the opposite of writing a book. It happens outdoors, in the air, and is gone as soon as it is made. Even the sound quietly joins the poem's two halves, since "work" and "walk" share their opening and closing consonants and sit side by side like the two parts of a day.
The poem has no rhyme, and its line endings (have, desert, work, enough, book, one, walk, sing) never chime. Judging by the tone, a rhyme might have promised a tidiness the speaker does not claim.
What makes "Cog" worth reading is its honesty about how despair and gladness coexist. It does not cure melancholy or argue truth into reach. The desert stays where it is. But the poem ends on the one word that is not a lack or a limit, and it gets there by shrinking from its heaviest word to its lightest. In a few dozen words it suggests that a person can be a small part of a machine, shut out of certainty, and still go out into a field and sing.