Literary Devices in Sonnet 18

A normal Shakespearean sonnet uses an abrupt uptick in end rhyme in the final couplet, shifting from ABAB quatrains to a GG couplet. To this couplet Shakespeare adds dense internal rhyme. In line 13, “breathe” and “see” are connected through assonance; that they land on the stresses of line’s third and fifth beats, respectively, accentuates the connection. In line 14, “lives” and “gives” injects an additional perfect rhyme to the couplet. This abundance of internal rhyme underscore the speaker’s point about poetry’s power.

While the sun is said to “lease” its short summer period, the speaker here claims that the beloved has “possession” of his fairness, or beauty. Unlike the sun which has a “too short” lease on summer, the youth has eternal possession of his “fairness.” This difference demonstrates that the youth is a more substantial beauty than summer and furthers the speaker’s belief that he is better than a summer’s day. Youth’s possession also aligns him with the higher landowning class.

The progression of verbs in this sonnet—shines, dimmed, declines, fade—reflects the passage of time. The speaker acknowledges that the summer’s day is transitory and uses this sequence of words to reflect the fading of brightness that happens over time.

The “his” in this line refers back to the subject of the preceding line, the “too hot” eye of heaven, or sun. Unlike the Petrarchan sonnet which uses the blazon tradition to fragment the beloved, the speaker fragments the vehicle of comparison; the sun’s complexion is dimmed.

Though the speaker initially rejects the blazon tradition, one could argue that he still compares his beloved to summer in order to show that the beloved is perfect. However, unlike a typical blazon, the speaker does not fragment the beloved into his distinct physical parts. He is treated as a whole person, “thou.”