Shall I compare thee to a summer's day?
Thou art more lovely and more temperate:
Rough winds do shake the darling buds of May,
And summer's lease hath all too short a date:
Sometime too hot the eye of heaven shines,
And often is his gold complexion dimm'd;
And every fair from fair sometime declines,
By chance or nature's changing course untrimm'd;
But thy eternal summer shall not fade,
Nor lose possession of that fair thou owest;
Nor shall death brag thou wander'st in his shade,
When in eternal lines to time thou growest,
So long as men can breathe, or eyes can see,
So long lives this, and this gives life to thee.
Like Marlowe's "Passionate Shepherd," Shakespeare's eighteenth sonnet almost defies analysis by virtue of its sheer simplicity. Of all the Sonnets that use the eternizing conceit, this may be the most straightforward (as well as the most influential, I would guess, on Elizabeth Barrett Browning). Its referential essence can be paraphrased in very few words: You're even nicer than a summer's day, and unlike summer, you won't fade away, because I've immortalized you in this poem.
I could remark on is its particular variation on the standard structural breakdown of the English sonnet form (three quatrains and a couplet). The movement of the poem's argument conforms to the 4-4-4-2 movement of the template as follows:
1st quatrain: Initial pattern established, in which the metaphorical vehicle ("summer") is shown to be wanting in comparison to the tenor ("thou"), and the theme of mutability (change, entropy, decay) is broached in the fourth line ("And summer's length hath all too short a date").
2nd quatrain: Pattern continued, with treatment of mutability topos expanded to two lines ("And every fair from fair sometime declines, / By chance or nature's changing course untrimm'd").
3rd quatrain: Pattern of comparison concluded, with further expansion of mutability theme to three lines ("fade," "lose possession," "Death," etc.), and addition of eternizing conceit ("eternal lines"). Not only has a third line been added to the mutability strain, but the lines have moved up the quatrain spatially, so that its last line (line 12) is now devoted entirely to the introduction of the eternizing conceit.
Couplet: Eternizing conceit expanded and concluded.
The effect of this gradual interweaving and expansion and contraction is to make the first twelve lines function in effect as one long stanza rather than as three discrete quatrains.
Am I trying too hard here? Maybe. You find something interesting to say about this poem. I mean, beyond the indisputable fact that it's a gorgeous piece of verbal music.
Speaking of gorgeous music, I can't read Sonnet XVIII with thinking of another haunting set of lyrics on summer and mutability: