Critical appreciation of dover beach

A recurring theme in the poetry of the Victorian period is a sense of loss and regret over ideas and beliefs that no longer hold value for the modern world. Oddly, this feeling sometimes coexists with a triumphal acknowledgement of the technological achievements that were transforming Europe (and much of the rest of the world) in the nineteenth century. Some poets, such as Browning and (to a lesser extent) Tennyson, emphasized the positive, while others, such as Matthew Arnold, focused on pain and loss.
Arnold's "Dover Beach" seems to allude to a dichotomy between the peaceful, beautiful scene of the English Channel at night and the reality of unhappiness and war:

And here we are as on a darkling plain
Swept with confused alarms of struggle and flight,
Where ignorant armies clash by night.

It is relevant to our analysis that at the time the poem was written in the 1860s, Britain and France were allies and had been so ever since the final defeat of Napoleon in 1815 and the restoration of the Bourbon monarchy. This was a reversal of the previous centuries of constant warfare between the English and the French. In referring to both the English and the French coastlines and the calmness of the setting, Arnold, possibly, is rejoicing in the peace between former enemies, but the irony, as one reads further, is that his emphasis is on the fact that in the world in general, peace is still lacking. As in other poems, such as "Philomela," Arnold draws a connection between ancient Greece and England. This "distant northern sea," the Channel (distant, that is, from the Aegean sea whose sounds were heard by Sophocles), brings the same sorts of troubling thoughts to an English poet that Sophocles must have had over 2,000 years earlier.
Arnold's resigned, regretful tone becomes apparent in these lines:

The Sea of Faith
Was once, too, at the full, and round earth's shore
Lay the folds of a bright girdle furled.
But now I only hear
Its melancholy, long, withdrawing roar

In my view this is a statement about the modern world's decline in religious belief or, more generally, about loss of faith in the older values. In the nineteenth century, intellectuals became increasingly secular, rejecting organized religion—not in the triumphant manner of the previous century's free thinkers such as Voltaire, Diderot, and Thomas Paine, but in a quiet, resigned way. "The Garden of Prosperine," written by Arnold's contemporary Swinburne, expresses the same idea, though in Swinburne's view, the finite nature of earthly life, though a source of regret, is also a kind of comfort:

We thank with brief thanksgiving
Whatever gods may be
That no life lives for ever;
That dead men rise up never
To Arnold, as well, earthly life is pain, and
....the world
Which seems to lie before us like a land of dreams....
Hath really neither joy, nor love, nor light

The only consolation, for Arnold, is that we are able to "be true to each other" in this dream-world, which is "so various, so beautiful, so new," though all of this is only on the surface. The "real" world is one in which there is "no certitude, nor peace, nor help for pain." The beauty of Nature, seen in the calm Channel and the Dover cliffs he describes at the start of the poem, is a facade. But it is the main external thing that provides comfort to man and motivates him to continue in a world where the older motivations—religion, flag, and country—no longer hold the meaning they once did.