SONNET XVIII
This sonnet is part of the Shakespeare's sonnet collection, composed by 154 sonnets.
Considering the layout the reader understand that is a sonnet organised in three quartrains and two couplet.
The poet starts making a rethorical question to an unknown person who he calls 'thou' (The arcaism of 'you').
The speaking voice makes a comparison between this figure and the summer that is the season of love, rebirth, and when the nature reaches its climax. Even so the unknown person is 'more lovely and more temperate' than summer, he is idealised by the poet through the word 'fair' (a constant beauty) that is repeated three times. There are two semantic fields around which the sonnet: the nature one and the time one. Indeed you can see words like 'winds', 'buds', 'nature course' etc but also words like 'day', 'summer', 'more', 'May', 'short', etc.
In the second quartrain the poet introduces the problem of his sadness: the 'thou' is a man so he will lose his 'fair' and he one day will die.
The third quartrain starts with 'but', and so the poet introduces an opposition: he says that the fair of the recipient will not fade; he will not lose his fair and he will not die, because in the poet's verses he will live forever. This is the solution that is explained in the couplet where the speaking voice makes a simile: "So long as men can breathe or eyes can see,
So long lives this, and this gives life to thee." Thus the poet wants eternalise his recipient 'thou' through his poetry.