particular poem, to "Sonnet 18" itself. The speaker states that the immortality of the young man's beauty depends upon three conditions:
As long as these three conditions are met, then the sonnet will give eternal life to the beauty of the young man.
William Shakespeare, at the end of this sonnet, is voicing a conventional idea about poetry: poetry is immortal. As our editors comment in a footnote, even during the Classical Age poets suggested that the poetry is permanent. Thus, Shakespeare is not vainly boasting here. Rather, he is asserting his agreement with the idea that poetry and art should last as long as humanity itself lasts. And since this poem has lasted for over 400 years, that notion appears to be true.