Sonnet 15

Everything that grows achieves perfection only briefly before time and decay pull it down; the young man is uniquely precious because he stands at the peak of youth, but even he cannot escape unless he reproduces.

Original
Modern
1 When I consider everything that grows
Whenever I observe all living things that emerge and develop,
2 Holds in perfection but a little moment.
Holds its perfection only for a short moment.
3 That this huge stage presenteth nought but shows
This huge world shows only temporary things
Allusion to the Globe Theatre and life-as-theatre; 'shows' = mere appearances, deceptions.
4 Whereon the stars in secret influence comment.
On which the stars secretly make their influence known.
Astrological belief that planets and stars influence human fate.
5 When I perceive that men as plants increase,
When I perceive that people grow like plants,
6 Cheered and checked even by the self-same sky:
Encouraged and held back by the same sky:
7 Vaunt in their youthful sap, at height decrease,
Show off with youthful energy, then decrease at their height,
Sap = vital energy; 'at height' = at their moment of greatest strength.
Wordplay: “Vaunt in their youthful sap, at height decrease”
  • boast in youthful vigor
  • 'sap' as vital life-force and 'sap' as to weaken—youthful vigor both peaks and erodes simultaneously
8 And wear their brave state out of memory.
And wear out their best state and get forgotten.
Volta The shift from observing nature's universal decay to recognizing the young man's personal crisis: 'Then the conceit of this inconstant stay' marks the moment philosophy becomes urgency.
9 Then the conceit of this inconstant stay,
Then thinking about this constant change,
Conceit = notion, thought; inconstant = changeable, unstable.
10 Sets you most rich in youth before my sight,
It makes you appear so radiant with vitality and youth in my view,
11 Where wasteful Time debateth with Decay
Where wasteful Time struggles with Decay
12 To change your day of youth to sullied night,
To turn your day of youth into a dark night,
13 And all in war with Time for love of you,
And all in war against Time for your sake,
14 As he takes from you, I engraft you new.
The speaker's first explicit statement of poetry's regenerative power: to preserve beauty is to 'engraft' it anew.
As it takes from you, I regrow you new.
Engraft = to implant, graft, or regenerate; horticultural image of renewal.
The Procreation Argument Fully Articulated

Sonnet 15 crystallizes the speaker's case for why the young man must have children. The sonnet establishes a universal law—all living things peak and decay—then applies it to the addressee with mathematical inevitability. The volta pivots from philosophy to personal stakes. The speaker's solution is dual: verse ('engraft you new') and, implicitly, biological reproduction. This sonnet completes a three-sonnet argument (15–17) that sets up the later claim that poetry alone can preserve beauty.

Stars and Cosmic Control

The reference to stars having 'secret influence' invokes Renaissance astrology, the belief that celestial bodies shape fate. By line 9, Shakespeare shifts from passive acceptance of cosmic forces to active resistance. The speaker doesn't accept that stars control the young man's destiny. This rhetorical move prepares the reader for the later sonnets' bolder claim: that verse, not the heavens, controls immortality. Mortality is not fate; it can be rewritten.

If this happened today

It's like watching a celebrity at the height of their fame—everyone knows they can stay relevant only so long. Without building something lasting (a business empire, children, a cultural legacy), they'll be forgotten in a decade. The speaker is saying: you're at your peak now, but time will diminish you unless you do something irreversible.