John Donne's metaphysical poem makes use of words per se as well as expanding their meanings by means of images or symbols. In his poem " A Valediction: Forbidding Mourning," employs metaphysical conceits, metaphors that are apparently paradoxical. In addition, Donne employs metaphysical wit, which is a clever use of reason to generate unusual metaphors that make use of science or mathematics in the persuasive argument of the poem.
With the argument that his and his wife's love is a spiritual one, much superior to "Dull sublunary lovers' love," Donne proposes that physical separation will not matter because it is not their bodies that unite them, but their souls. Using terminology from science and mathematics, Donne first formulates a metaphor based upon the malleability of gold. For, just as gold will expand and can be molded into something beautiful, so, too, can their love develop and become beautiful as the distance between them increases:
but an expansion,
Like gold to airy thinness beat.
If they be two, they are two so....
Then, Donne employs a mathematical metaphor with the instrument of a compass that was used on maps to measure distance,
twin compasses are two;
Thy soul, the fix'd foot, makes no show
To move, but doth, if th' other do.
In this metaphor, like the gold that is refined into a thinner, more beautiful piece, the one leg of the compass anchors the other that stretches for [travels] across the map, leaning some to accommodate the reach of the other leg, and strengthening the extension of this leg.
Through the two metaphors of gold and the compass, both of which are "refined," or made better by the poet's distance from his wife, a distance that strenghtens their spiritual love, Donne expresses the superiority of their love to the mere physical:
But we, by a love so much refined That
ourselves know not what it is,
It is so pure and perfect that even the poet and his wife cannot fully comprehend this spiritual union.