GIVEN THE MANY USES and abuses of the word "freedom," it stands to reason that our poetic history has produced a little epitome of its vexations. The concept of a "free" poetry is all but an oxymoron: Poetry is concerned, above all, with the question of its own accounting; in the eighteenth century it was even referred to as "numbers." Yet what major language has been untouched by the revolution of "free verse"? Almost a hundred years after Ezra Pound trumpeted Imagism, venerable traditions have succumbed to the ametrical: Arabic, Russian, Hindi. But even Pound and Eliot didn't believe vers could be truly libre, Frost ridiculed it, neoformalists rallied against it, and internet curmudgeons still wax irate on the subject.

No, there is something about poetry — about language use itself — that sits uneasily with "freedom." Maybe it's the terror of babble (the verbal mode of insanity, dementia, and catastrophe). Maybe it's that for tens of centuries, scribes and grammarians have been mainstays against the cultural losses — and dysphasias — incurred by history: losses of manuscripts, of entire languages. They have also been the ones to sniff at an improperly used meter, a "shapeless" ode, or a qasida that seemed just "a string of pearls," all rhyme and no reason. Grammar is hard to master. Meaning is easily lost. To mess with it, to mess with language, to play with it (much less play with it without a net) drives pious types bonkers. And on the other side are the ones who have played with language relentlessly, also for thousands of years, the rhymers, punners, riddlers, and innuendo-peddlers who have simultaneously performed the shamanistic duties of the bard: keeper of the culture's stories, its knowledge, its word-hoard. Frivolous and serious, mischievous and magisterial, poets play both sides of the coin of freedom — heads they study ("the scholar's art," Wallace Stevens called poetry), tails they frisk. If freedom and poetry seem paradoxical, freedom and poets are all but identical.

Here is a telling story about freedom and poetry. In the early 1770s (the same time, not coincidentally, that revolutions were brewing in America and France), European poets conceived a passion for Pindar, the great choral poet of Greece's golden age. Diderot's encyclopedia referred to Pindar's style as one of beau désordre; the German philosopher and poet Johann Herder called his meter gesetzlos, "lawless" (he said this approvingly). Herder's friend Goethe, following Horace, praised Pindar as "borne on free rhythms" ("numerisque fertur/lege solutis") like a mountain river, and adopted an idea of the rhythmic dithyramb for his own purposes. Thus was the romantic ode first born. It was only in 1811 that a new edition of Pindar, based on different lineation, revealed how unfree those "disordered" dithyrambs actually were. According to these classicists, Pindar had in fact cleaved to a rigid metrical scheme repeated in corresponding strophes.

The same mistake, in fact, had been made a century earlier in England. Abraham Cowley had been taken with a similar enthusiasm for Pindar and his liberties. He published some imitations in 1656 called Pindarique Odes, which created a fashion for nonce "pindarics" in English society. They were correspondingly unveiled as a kind of fraud in 1706, when the real secrets of Pindar's metrics were revealed, and the form fell int...