The multi-dimensional text of The Tempest has inspired a rich variety of critical analyses. Despite an atypically strict adherence to the unities of time and place, the play operates in an open, fluid atmosphere of the natural and supernatural that evades ready interpretation. In seeking to examine the numerous contexts which may have informed the writing of the work, recent critics have focused on the character of Prospero and the nature of his magic, as well as the drama's sources and structure.
The Tempest's ability to spark such a variety of interpretation is due in part to the fact that the play's plot and situation defy a single clearly identifiable source. Since the eighteenth century, scholars have identified William Strachey's epistle account of the 1609 shipwreck of the Sea Adventurer while en route to the Virginia colony as a primary source for the plot and setting of the play. Prior to 1960, other potential source materials cited were Montaigne's writings on primitive life in the New World, folkloric magician literature.the commedia dell'arte tradition, and Ovid's Metamorphoses and the Aeneid. Recent scholarship has expanded source studies of The Tempest in several areas. Since 1960 critics have given closer scrutiny to the relationship between the play and Latin literature, especially the writings of Vergil and Ovid. John Gillies (1986), for example, explored Ovidian themes in the play, contending that Shakespeare's presentation of "the official portrait" of the Virginia colony is in fact Ovidian in its emphasis on fruitfulness and temperancr. In addition to this expanded exploration of classical sources, scholarship has focussed on new colonial perspectives in the text. Since the turn of the century, scholars have cited the literature of New World pamphlets in circulation at the time the play was written as evidence that the adventures of the Virginia colony were a source for the setting and political views of The Tempest. This view was vehemently rejected by critics who saw the Bermuda setting of the play as a refutation of Virginian sources. In recent scholarship, Gillies has continued this discussion in his article on the Virginian influence, writing that "with its emphasis on self-discipline, its apparent endorsement of absolute power as a necessary means to general prosperity, and its no-nonsense attitude towards savagery, The Tempest can be seen to reflect not only the events of 1609, but the mood which gave them significance".
The debate over sources often frames the discussion of the play's structure. In particular, critics have viewed the masque of Ceres in Act 4 as the unifying element of the play, expressing political and philosophical concerns in a form then fashionable for court performances. Glynne Wickham (1975), for example, has commented that "The Tempest … emerges … as a single unified work of art firmly held together by the successful incorporation of a masque and anti-masque within the dramatic structure of a stage-play." Similarly, Gillies also has viewed the masque as a crucial structural feature, the means by which the Virginian motifs are translated into Ovidian forms.
For the majority of contemporary critics, the predominant unifying element of The Tempest is the character of Prospero. Perhaps no other character in Shakespeare is seen to be as crucial to the structural and thematic integrity of a play than Prospero is to The Tempest. David Sundelson (1980) has commented that "… the play belongs to Prospero in a way that seems downright un-Shakespearean.… [Prospero' s] very presence restores the world to harmony." Prospero's dominance in the action has led to a vast critical exploration of his powers and motivations. While earlier scholarship tended to concentrate on Prospero's renunciation of magic as a key element of the play, criticism after 1960 has moved towards a broader study of Prospero as a multifaceted coalescence of diverse folkloric and intellectual sources. This expanded study of Prospero's magic has resulted in a bountiful mix of critical interpretations. Regarding Prospero as an example of the neoplatonic magus, Barbara Traister (1984) has placed him within the context of European magical thought of the fifteenth and sixteenth centuries. For Traister, "Prospero becomes the supreme embodiment … of the paradoxical figure of the magician: a man of great power who can force or influence nature to alter her course for him, but a man … who is, finally, not a god, only human, and thus faces boundaries beyond which he must not pass." Modifying this view, Harry Berger (1969) and Barbara Mowat (1981) have characterized Prospero as a frustrated idealist whose pursuit of magic and the liberal arts serves as an escape from a mundane world. Berger has analyzed as "… an ancient and familiar psychological perplex connected with excessive idealism and the longing for the golden age; a state of mind based on unrealistic expectations." Another important trend in criticism written after 1960 has been to explore psychoanalytic readings of Prospero and his relationship with the drama's other characters. Critics such as Sundelson have anallyzed the play as a study in Prospero's paternal powers. His anxiety over Miranda's budding sexuality, emphasized by Caliban's sexual threat to Miranda, and the need to find a suitable mate for her, is seen as a motivating force behind Prospero's actions. While pointing out the weaknesses behind a psychoanalytic reading of The Tempest, Orgel has commented on the lack of mothers in the play, emphasizing Prospero's hostility towards mother figures in his quest to be both mother and father to Miranda.
Scholars have gained further insight into the character of Prospero by examining his relationship with Caliban.
Departing from older critical notions of Caliban as either the symbol of the uncivilized savage or the embodiment of human suffering, recent criticism has seen him both as a reflection of Prospero's conflicts and ambivalences and as a universal symbol of human attempts to understand reality. As Berger has noted, the parallels between Prospero and Caliban are clearly drawn, yet Prospero fails to recognize them. In an introduction to the play, Stephen Orgel (1987) has demonstrated that Prospero's attitude towards Caliban represents his conflicting identity as a ruler. Although Caliban's claim to the island through his mother is a threat to Prospero's authority, in fact "… it is Caliban who legitimizes Prospero's rule…he reminds us that authority may claim to derive from heaven, but in practice it depends on the acquiescence … of those who are governed by it." Prospero's ambivalence towards Caliban mirrors, then, his ambivalence towards his authority and power as a ruler, an ambivalence that led to his overthrow as Duke of Milan. Prospero's acceptance of Caliban at play's end, Orgel argues, represents a symbolic acceptance of Prospero's own role in his political exile. In a related view, Kott emphasizes Caliban's function as a mythical hybrid, essential in the resolution of "binary oppositions"—good and evil, mortality and immortality, male and female—that Prospero struggles to resolve in his own nature. Psychoanalytical approaches to The Tempest, such as those of Sundelson and Robert M. Adams (1989), the conflict between Prospero and Caliban over ownership of the island reflects the struggle between maternal nad paternal forces. Adams, for example, maintains that "seeing Prospero and Caliban as super-ego and id or as father and son may suggest varieties of intimate interaction between two unreconcilable elements of an unbreakable unity-interaction that controls much of the play." This "unbreakable unity" is acknowledged by Prospero's ultimate acceptance of Caliban as his own. Other scholars, however, emphasize that Prospero's inability to control Caliban through his magic is seen as one of Prospero's central limitations. Traister has noted that Caliban represents not only Prospero's limits but magic's as well, revealing that magic cannot alter a human soul. Despite Prospero's ambivalent feelings towards Caliban and the limitations he represents, the evolution of Prospero's relationship with Caliban is viewed as a symbol of Prospero's movement towards the attempted resolution of inner conflict, acceptance of responsibilities, and reentry into the world.