"The rarer action is / In virtue than in vengeance" (5.1.2). This is Prospero's startling revelation after years of living in exile and plotting his return to Italy. The Tempest's emphasis on mercy and forgiveness are hallmarks of Shakespeare's "romances," four plays (The Tempest, Pericles, The Winter's Tale, and Cymbeline) written late in the playwright's career. Prospero's capacity to forgive those who have betrayed him, Miranda's empathy, Ariel's mercy, and Gonzalo's thoughtfulness dramatize the triumph of the human spirit.
Mercy does come naturally to man in the state of nature. Miranda, full of empathy and sympathy, is evidence of this. Prospero and the others in the play do not come to mercy so easily because they have been ruined by civilization.