Song Meaning
The speaker confronts a beloved about the inevitable decay of their beauty, framing it as a siege by time. "Forty winters" isn't just a number; it's an active force digging "trenches" into a "beauty's field." The vibrant "youth's proud livery" will become a "tattered weed," highlighting a stark contrast between present admiration and future neglect. This sets up a profound anxiety about legacy and the ephemeral nature of physical attractiveness.
The central tension arises from the question of where this beauty will reside when it's gone, and the shame associated with a purely internal, unshared memory. The imagined response, "within thine own deep-sunken eyes," is deemed "all-eating shame and thriftless praise." This suggests that beauty unprocreated, unpassed on, is ultimately a wasted resource, a source of regret rather than fulfillment.
The poem's power lies in its stark, almost brutal imagery of aging and its proposed solution: procreation. The idea of a "fair child" becoming an "excuse" for past beauty, "summing" up the speaker's worth, is a pragmatic, almost transactional view of legacy. This "succession" offers a form of renewal, a way to be "new made when thou art old" and keep one's "blood warm" against the cold of mortality.
This lyrical argument is effective because it taps into a deep-seated human fear of fading and being forgotten. By personifying time as an enemy and beauty as a quantifiable asset, the speaker creates a compelling case for ensuring that beauty's value is preserved and extended through offspring. The final couplet offers a potent vision of continued vitality, a potent counterpoint to the initial depiction of decay.