By far the most common literary devices used in Shakespeare's sonnets are metaphors and similes. Another common literary device is poetic conceits, but it is Shakespeare's metaphors and similes that have made them nearly immortal, as he himself suggested. He had a gift for figurative expression, and he knew it, and he used it in his poetry and in his plays. A striking characteristic of Shakespeare's metaphors and similes is that they are almost always simple, natural, unpretentious, common, ordinary, familiar, one might even say "democratic." He did not have an academic education like many contemporary poets. He had "small Latin and less Greek," as Ben Jonson said of him. So he made a virtue of necessity and refrained from drawing on classical literature for his comparisons. Instead he drew on nature and on everyday sights. The one sonnet that best illustrates Shakespeare's simplicity is Sonnet 73.
That time of year thou mayst in me behold
When yellow leaves, or none, or few, do hang
Upon those boughs which shake against the cold,
Bare ruin'd choirs, where late the sweet birds sang.
In me thou see'st the twilight of such day
As after sunset fadeth in the west;
Which by and by black night doth take away,
Death's second self, that seals up all in rest.
In me thou see'st the glowing of such fire,
That on the ashes of his youth doth lie,
As the death-bed, whereon it must expire,
Consum'd with that which it was nourish'd by.
This thou perceiv'st, which makes thy love more strong,
To love that well, which thou must leave ere long.
He evokes the images of trees with yellowing leaves and totally bare trees shaking in the wind; twilight; night; a dying fire. He compares birds singing in the trees to people, perhaps children, singing in church choirs.
Each of the three stanzas in this sonnet contains a metaphor within a metaphor. It is these that make this particular sonnet so remarkable. In the first four-line stanza the poet compares his time of life and his physical appearance to late fall, when the trees are almost totally bare. Then he compares the leafless boughs to ruined choirs—the part of the church behind the altar in which the choir sings. An example of a poetic conceit is his saying that the boughs shake against the cold. He is suggesting that they are cold because they are naked, while in fact they cannot feel the cold but are shaking because of the wind.
In the second four-line stanza, the poet compares his time of life and his haggard appearance to the twilight time of day, a time when the sun has set but a little light remains in the sky. Then he compares the coming on of night to death.
Finally, in the third four-line stanza he compares his condition to the glowing remains of a fire. Then he compares the ashes of the metaphorical fire to a bed on which the fire is slowly dying and will eventually be consumed by its own ashes. Each of these three stanzas contains a metaphor within a metaphor, and yet all the images are easy to visualize because they are all so familiar and unpretentious.
Sonnet 73 is crowded with metaphors, but in some of Shakespeare's other sonnets he is frugal with imagery. He uses one single image which is all the more striking because it stands alone. There is little difference between a metaphor and a simile. Perhaps Shakespeare's most dazzling simile is to be found in his Sonnet 29, which begins with:
When in disgrace with fortune and men's eyes,
I all alone beweep my outcast state...
He dwells on his melancholy thoughts until he suddenly remembers the paramour to whom this sonnet is addressed.
Yet in these thoughts, myself almost despising,
Haply I think on thee, and then my state,
Like to the lark at break of day arising
From sullen earth sings hymns at heaven's gate....
The image is of a common skylark, but we visualize it leaving the ground in one line and soaring all the way up to heaven in the next. The alliteration and consonance of "S" sounds is profuse and suggests a real outburst of joyful singing which contrasts with all the gloomy thoughts that went before. The "S" sounds are contained in "arising," "sullen," "sings," "hymns," and "heaven's."