The principal image in this poem is the use of the sound of the waves washing the pebbles to represent the loss of religious faith in the Western world. The beach Arnold is describing is not a sandy one but a cold strand covered with pebbles. The incoming waves roll the pebbles in one direction and then roll them back towards the ocean as the surf retreats. This has been going on for billions of years. It reminds the poet of the past, and he thinks of Sophocles, the Greek tragedian who lived from around 496 b.c.e. to around 406 b.c.e. and is best known for his play Oedipus Rex.
Arnold is indebted to Sophocles for comparing the sound of the rattling pebbles to "the turbid ebb and flow / Of human misery." To Arnold the same identical sound, which has been going on continuously for some twenty-four hundred years, is a metaphor for the loss of religious faith which has been accelerating since at least the time of the French Revolution.
The poem is important because it deplores what is happening to people. With the loss of traditional religious faith people can find no meaning to their lives. Yet it is impossible for intellectuals like Arnold (and so many others) to pretend they still believe in what the established churches teach when scientific knowledge is relentlessly undermining the authority of the churches and of the Bible. This so-called "crisis of faith" was a subject of great importance to writers during the nineteenth and early twentieth centuries. It still is a matter of importance and controversy today. Is there a God? Or is there nothing but matter and empty space?
The description of the pebbles being endlessly and tirelessly washed and tumbled by the sea is the best part of "Dover Beach" because it is the most poetic.
Listen! you hear the grating roar
Of pebbles which the waves draw back, and fling,
At their return, up the high strand,
Begin, and cease, and then again begin,
With tremulous cadence slow, and bring
The eternal note of sadness in.
Arnold is thought to have composed this poem around 1850. Science had still more unsettling discoveries to offer. Charles Darwin published his Origin of Species in 1859 and started a controversy between "Darwinians" and "creationists" which seems to have no foreseeable compromise or conclusion. World War I was a terrifying event for Europeans because it seemed to represent a return to savagery. Thinkers like Arnold in the latter part of the nineteenth century could see the catastrophes that were coming. He concludes his sombre, fatalistic poem with the following lines:
Ah, love, let us be true
To one another! for the world, which seems
To lie before us like a land of dreams,
So various, so beautiful, so new,
Hath really neither joy, nor love, nor light,
Nor certitude, nor peace, nor help for pain;
And we are here as on a darkling plain
Swept with confused alarms of struggle and flight,
Where ignorant armies clash by night.
Matthew Arnold was expressing the apprehensions and spiritual confusion that so many people of his generation were beginning to experience and so many people continue to experience today. That is why his "Dover Beach" continues to be read and studied. It is not only poetry, but history and philosophy. It is a sobering thought that the world has "neither joy, nor love, nor light, nor certitude, nor peace, nor help for pain." Arnold heard the "melancholy, long, withdrawing roar" of comforting religious faith which still seems to be withdrawing in the twenty-first century.