I am silver and exact. I have no preconceptions.
Whatever I see I swallow immediately
Just as it is, unmisted by love or dislike.
I am not cruel, only truthful‚
The eye of a little god, four-cornered.
Most of the time I meditate on the opposite wall.
It is pink, with speckles. I have looked at it so long
I think it is part of my heart. But it flickers.
Faces and darkness separate us over and over.

Now I am a lake. A woman bends over me,
Searching my reaches for what she really is.
Then she turns to those liars, the candles or the moon.
I see her back, and reflect it faithfully.
She rewards me with tears and an agitation of hands.
I am important to her. She comes and goes.
Each morning it is her face that replaces the darkness.
In me she has drowned a young girl, and in me an old woman
Rises toward her day after day, like a terrible fish.

“Mirror” by Sylvia Plath: A Critical Appreciation

The personified mirror is “silver” (in appearance) and “exact” (it reflects the image accurately). By itself the mirror does what it is supposed to do, it mirrors. Not being opinionated, it is unbiased, reflecting the image exactly as it is.

Traditionally the poem has been considered to deal with the subjects of time and appearance; and the female narcissistic trauma for beauty and youth robbed by time. Worried about the signs of age, the speckles and wrinkles appearing on her face, she temporarily seeks solace as “she turns to those liars, the candles or the moon”, only to turn back to the mirror who reflects her faithfully.  

However, in a metaphoric shift, the mirrors becomes a lake where the woman has drowned a young girl, and like a terrible fish, an old woman rises towards her. Here the mirror becomes a more complex entity than a neutral reflector of images. If the ‘old woman’ is the present truth, there is no point in reminding the drowned young girl, unless there is a tacit politics of comparison involved here. It is the sheer commercialization of the female body which is valuable until it is young.

Hence, the truthful “eye of a little god” that the mirror claims to be his, is the gaze of the chauvinist male (‘god’) that defines the truth about female body and her identity. The first stanza of the poem thus appears to be the solidification of a patriarchal order that dictates truth and objectivity for the woman, herself torn between what the society expects to her as a wife or mother, and her own quest to find her identity as an individual or an artist.