The poem enjoys recognition for its textures of sight and sound, historical allusions, and unusual structure. The poem's unity rests upon its visual of imagery of moon, moonlight, land and plain and upon its aural imagery of grating and withdrawing roar (turned into alarm and clash) and how those images interrogate its central theme of liminality.
The first stanza, structured like a Petrarchan sonnet, turning on "Listen!" advances the contrast between tranquil visions of 'glimmering' and 'gleams' in the octave and the music 'of pebbles' as they rhythmically sing their 'tremulous cadence' in their 'eternal note of sadness.' The liminal interface of the 'waves' with 'pebbles,' 'where the sea meets the moon-blanched land,' presents the borders of two worlds, two historical epochs. Present and past, space and time unite in their constitutive liminalities.
The second (sestet) and third stanza (octave) invert the Petrarchan form, and locate the 'turn' (volta), it would seem, in the octave (though the case for the sestet containing the volta can also work). If the 'sea of faith' turns from what 'Sophocles heard...on the Aegean' an inversion seems the likelier structure. The 'eternal' music of liminality, contends the voice in the poem, has bequeathed to us the Oedipus tragedies, representations of the 'ebb and flow of human misery.' There is nothing new under the moon or fullness of 'tide.' Mediterranean, English and French seas touch in the vastness of the contiguous waters that cover the earth, 'down the vast edges drear/And naked shingles of the world.' Their unities both fetter and liberate, and conduce to love and war.
The final stanza, something of a odd (even truncated) villanelle, concludes the poem in 3 tercets with a jarring enjambment. The closing argument calls to love, and despite the possible presence of an auditor within the poem hinted at in the first stanza, discourages 'love' as a nickname for a lover present, hearing the voice of the poem. Instead, the strange villanelle is an apostrophe to love, eros. Love, as the sonnet-villanelle structures strongly suggest, is the subject of "Dover Beach." The sonnet and the villanelle have always enjoyed the status of 'love poetry' in the Western tradition. Arnold makes good use of them in this poem.
The echoes of love and faith that play out in "Dover Beach" brush up against the erotic reduction. The voice in Arnold's poem laments the withdrawl of the 'Sea of Faith' into the 'ebb and flow' of the waters of the earth. This receding of faith, once 'bright' and 'full...round earth's shore,' marks a 'melancholy' retreat from the Victorian world which has beaten it back with something new. The 'darkling plain' where the poem's voice and love find themselves is the very facticity of their predicament. How can this lost voice be 'true' to love, and what would that look like (how would that appear) if not as the phenomenological moment where love gives itself, whose very giving and givenness finds the lost voice with its call from the anonymous grating of pebbles, shingles, and the high strands of phenomenality?