In his essay "On Cannibals," Montaigne continually asserts that what is natural is synonymous with what is good, and that Nature herself ought to be the light by which human action is guided. It is not surprising, then, that he presents a highly idealized characterization of the natives of the New World. He perceives these "cannibals," as he calls them, to be men who live in the way Nature intends them to live, unadorned and unfettered by modern civilization. Montaigne goes so far as to claim to have found in these cannibals the "golden age," spoken of so often by philosophers and poets as merely an unattainable dream. He boldly asserts that in the character of these people, all of "the true, most useful, and natural virtues and properties are alive and vigorous."

The characterization of Ariel and Caliban in The Tempest is significant in relation to Montaigne’s essay, which was one of Shakespeare's main inspirations for the work. In "On Cannibals" and in The Tempest, both Montaigne and Shakespeare explore the relationship between human nature and modern civilization. Montaigne’s idealization of the cannibals contrasts sharply with Shakespeare’s unsympathetic portrayal of the brutish Caliban, whose name thinly veils the influence of Montaigne’s essay. Whereas Montaigne’s cannibals are praised as "wild fruits," produced by nature in her ordinary way and without any artificiality, Shakespeare’s cannibal appears to be as pathetic, crass, and vulgar as any individual can possibly be portrayed. This seems to imply that Shakespeare’s portrayal of Caliban is a direct attack against the form of wistful idealizing of Nature that Montaigne is so fond of. Yet the complexity of The Tempest lies in its essential ambiguity. This ambiguity stems from the juxtaposition of the brutish and pathetic character of Caliban with the sprightly and sympathetic character of Ariel. Both Caliban and Ariel are natives of the island, and hence can be thought of in terms of Montaigne’s cannibals. By analyzing the characterization of these two characters in relation to Prospero, one comes closer to determining how The Tempest as a work of art responds to and challenges Montaigne’s essay. Lying at the root of Shakespeare’s response to Montaigne is a differing conception of human nature and the extent to which modern civilization suppresses it.

Ariel and Caliban can both be viewed as the "colonized subjects" of Prospero, and the differing attitudes of these subjects towards their master is indicative of the differing ways in which human nature responds to modern civilization. Both Ariel and Caliban are individuals undoubtedly oppressed by Prospero, yet each develops a different relationship to their master based on their natural character as well as their prior circumstances. The scenes of The Tempest are structured so as to emphasize the differing characterizations of Ariel and Caliban in their relationship to Prospero. Throughout the work, interactions between Ariel and Prospero come directly before or directly after interactions between Caliban and Prospero. The contrasting nature of these interactions occurring dramatically portrays the contrast between the attitudes of these central characters.

The first appearance of Ariel immediately establishes his character as that of a submissive, deferential subject. His language is that of a slave who binds himself to his master without question:

Ariel’s self-effacing willingness to serve Prospero contrasts strongly with Caliban’s attitude of sardonic rebelliousness exhibited in the same scene. Whereas Ariel greets Prospero with an affirmation of his greatness, Caliban greets him with a curse:

Caliban’s apparent hatred for Prospero is evident in much of his speech, which consists predominantly of curses similar to this one. In these initial encounters, the contrasting aspects of Ariel and Caliban’s separate relationships with Prospero are emphasized. Ariel is portrayed as a submissive servant, while Caliban is characterized as rebellious and spiteful.

Caliban's first speech emphasizes the conflict that arises from his lack of gratitude towards his master. Prospero, having drawn Caliban away from his savagery and towards modernity, believes that Caliban owes him a debt of gratitude. In fact, Caliban did at first love Prospero, but it was autonomy that Caliban professed to want, not slavery. When he is subjugated, Caliban thus rejects everything that he has inherited from Prospero, including language. Caliban essentially feels betrayed, and this is evident in the tone that is used to address Prospero in his first speech:

Unlike Ariel, Caliban has no future promise of freedom that will justify an attitude of deference. His rebellious attitude is a reaction to his feeling that he is being unjustly used and subjugated.

It is Prospero’s art which controls both Ariel and Caliban, binding them to his authority as their master. Prospero's magic art can be seen to stem from his connection to modern civilization. One can see how he utilizes his art, akin to modern technology, in order to suppress and subjugate. He is portrayed as a colonizer who exploits the innocence of his subjects to his own advantage. Prospero uses his power over Caliban in a malicious, vengeful manner. He influences Caliban by intimidating him with threats of bodily discomforts and annoyances. Caliban dramatically emphasizes the extent of this power when explaining why he does not simply run away:

Prospero’s relationship towards Ariel is of a quite different nature than his relationship towards Caliban. Whereas Prospero uses his magic in order to subjugate Caliban, he uses it in order to free Ariel from the curse of Sycorax. The submissive attitude of Ariel in his relationship with Prospero stems from the debt that this engenders in him towards his master. When Ariel becomes so bold as to ask Prospero when he is to be set free from his authority, Prospero has only to remind him of this debt and Ariel’s submissive attitude is restored:

Ariel is content to serve his master only to the extent to which it ensures his future release. In a sense, he is repaying the debt he owes to Prospero by willingly subjugating himself to him. Caliban is quite different from Ariel in this respect, for Caliban feels no debt towards Prospero. Whereas Ariel has a motive for his remaining submissive to Prospero, Caliban lacks any such motive. Lacking any feeling of debt in his relationship to Prospero, Caliban thus develops the rebellious and accusatory attitude that characterizes him through much of the work.

One of the most significant differences in character that separates Ariel from Caliban is the way in which each uses language. Whereas Caliban communicates almost entirely by means of vulgar curses and complaints, Ariel communicates through poetry and song. Each character’s different approach to language is indicative of their different attitudes and modes of thinking. Ariel’s language is ordered and stylistic. It betrays a mind at ease with his environment, a mind in which creativity and wit have sufficient room to develop. Caliban’s language, on the other hand, is the product of a mind surely in a state of general discomfort and ill ease. Caliban, unlike Ariel, is not of the mind to produce anything remotely similar to poetry or song. Caliban has entirely rejected language itself:

This is significant in that by rejecting language, Caliban is rejecting knowledge itself. With knowledge comes a realization of one’s inadequacy, and Caliban prefers to remain in that more primitive state of blissful ignorance. This is not surprising, for Prospero has given Caliban the tools of communication and self-knowledge, but has failed to give him the freedom and self-responsibility with which it is necessary to enjoy them. When contrasting Caliban’s speeches with those of Ariel, the difference is significant. Ariel’s songs are filled with alliteration, assonance, rhyme and meter:

This is language suitable to a sprite with little care, almost absurdly childish in its nursery rhyme character. Ariel's language here is pleasant and musical, clearly the product of a clever mind, yet it possesses none of the insight and import that is characteristic of similar characters in other Shakespeare works, such as The Fool in King Lear.

It is not until the second half of The Tempest that one can accurately make any judgements on the characters of Ariel and Caliban. Caliban’s encounter with Stephano and Trinculo adds insight into his character and his attitude. Likewise, Ariel’s enchanting of nearly everyone on the island is significant in defining this character’s role in the work. It is possible to view Caliban in the first half of the work as a slave who is rebelling against his oppressive master. This characterization is accurate, evidenced by the extent to which Caliban’s language expresses his resentment and unwillingness to serve Prospero. Yet when Caliban encounters Stephano and Trinculo with their "celestial liquor," he willingly subjugates himself to them. Caliban does not ask them for his freedom, as would be expected. Rather, he begs them to be his master, even his god. Caliban thus shows himself to be incapable of autonomy. In his relationship to Stephano, Caliban is even more pathetic than in his relationship to Prospero, for he abandons his rebellious attitude for one of hero-worship and grovelling. By putting himself in willing slavery to Stephano, who is no more than a drunkard and a buffoon, Caliban shows himself to be truly in a pathetic state. The vicious curses that he had constantly sent to his old master Prospero are replaced by requests to lick the shoe of his new master. A drunk Caliban even attempts a poetic song for the first time, and makes a fool of himself by stumbling over his name:

He joyously hails his new situation as "Freedom, high day," unaware that he is simply stepping into another set of chains, this time those of liquor. Caliban becomes a more sympathetic character in the second half of the work. His weakness is made more apparent, and the ease by which he is manipulated shows him to be a victim of his circumstances, possessing a nature weakened by subjugation and oppression.

Although the characterization of Caliban shows him to be a more pathetic character as the play progresses, the characterization of Ariel displays quite the opposite. Ariel occupies the most important role of the play during the last two acts. It is Prospero who conceives the ideas for enchanting the shipwrecked Italians, but he can only carry them out with the aid of Ariel. In the same way that Ariel is dependent upon Prospero for his freedom, Prospero is dependent upon Ariel for the fulfillment of his plans. Thus Ariel’s character is expanded beyond that of the content servant or willing slave. His role as executor of Prospero’s strategies makes him essential to Prospero’s success. This entails a significant reversal in roles. Ariel becomes the one in control, for it is his power of enchantment upon which Prospero is dependent. Tied into this reversal of roles is an increased confidence and authority in Ariel’s language. In his speech to Alonso, Antonio and Sebastian in Act III, Ariel condemns these three in the same type of authoritarian language which had previously been reserved only to Prospero:

Ariel’s use of language as a means of intimidation is quite different from his sprightly poems and songs of the first two acts. His changing use of language is evidence of a changing attitude. As Ariel comes closer to his freedom, his demeanor becomes more confident and less submissive. He is becoming more independent, and thus more strong in character. Where the second half of the work shows a Caliban increasingly destitute and pathetic, it shows an Ariel increasingly self-assertive and autonomous.

The conclusion of The Tempest shows Prospero regaining his dukedom, Ariel finding his freedom, and Caliban resigning himself once again to the authority of Prospero. Although it seems at first to be a pleasant state of affairs, a closer look reveals it to be quite the opposite. Prospero is surely unfit to be a duke, as his overbearing and oppressive nature throughout the play attests to. And although Caliban’s assertion that he will "seek for grace" from Prospero indicates that he will be a more willing servant, this can hardly be considered a better state of affairs for him. It seems as if Ariel, in winning his freedom, is the only one of these characters whose state is truly better than it was at the opening of the play. This is significant in that among these characters, the distinguishing characteristic of Ariel is that he is not human. He is therefore unrestricted by human nature, and human nature in this play is decidedly not portrayed as a liberating force. Especially in the relationship between Prospero and Caliban, one sees the destructive force that exerts itself when a human being takes it upon himself to control another. Shakespeare's word play in naming his characters emphasizes this idea. In the same way that Caliban’s name can be rearranged as "Canibal," the letters in Prospero's name can be rearranged to spell out "Oppresor." This can hardly be seen as coincidence, for in the relationship between the two, one is able to discern that Prospero wields his intelligence and modernity as oppressive forces.

Montaigne exalts the cannibals for having maintained a civilization so natural and unartificial, but Shakespeare asserts that when exposed to modern civilization, the cannibals become no different than the Europeans. The moderns employ their magic powers – intelligence, technology, and liquor – to subjugate and oppress the cannibals. Yet the cannibals willingly allow themselves to be captivated and entrapped by the spell of modernity. Whereas Montaigne praises the cannibals and places blame on modern Europeans, Shakespeare asserts that neither the cannibals nor the Europeans deserve praise – save for a few rare individuals, they are both equally pathetic.