Satire is writing (prose, poetry, or drama) that employs wit and humor in order to ridicule vices, follies, and abuses or hold up to contempt the faults of individuals or groups. Irony is often an element of satire, as is sarcasm.
In Gulliver's Travels, through the use of satire, Swift exposes the corruption and defects in the political, social, and economic institutions of England. In each of the four voyages, Gulliver is taken to a different and remarkable world where he comes to realize the very flawed nature of his English society. In Book I, Gulliver travels to the island of Lilliput. After being shipwrecked, Gulliver awakens to find that he is tied down by people who are only six inches tall. Although Gulliver is held captive, his genial disposition wins over the people and he is eventually granted freedom. However, while he is there, Gulliver becomes aware of the similarities of the Lilliputian affairs of state and those of England. For instance, the Lilliputians speak of the threat of invasion from the island of Blefuscu (France), the "other great empire of the universe." There has been an "obstinate" war between the two nations for "six and thirty moons past" over the procedure of breaking an egg.
That all true believers shall break their eggs at the convenient end; and which is the convenient end, seems, in my humble opinion, to be let to every man's conscience, or at least in the power of the chief magistrate to determine.
In this passage, Swift satirizes the dispute in England between the Catholics (the big-endians) and the Protestants (the small-endians). King Henry VIII, who "broke" with the Catholic Church, King Charles I, who "lost his life," and King James, who lost his "crown" are all alluded to in the passage.
In another instance, after Gulliver is allowed into court in Lilliput, he notices how the candidates for high office obtain their posts,
When a great office is vacant, either by death or disgrace . . . five or six of those candidates petition the emperor to entertain his majesty and the court with a dance on the rope.
Here, Gulliver implies that the candidates walk on a tightrope, and the one who can jump the highest obtains the position. The satire here is that the candidates for office in Britain are appointed, not by their intelligence or governing skills, but instead by their social position and status.
Furthering this satire of the politicians and their lack of honor, Gulliver observes another challenge for political appointments when candidates for office are required to "leap over the stick, sometimes creep under it, backward and forward, several times. . . ." If the candidates successfully perform these feats, they are rewarded with silks of varied colors, indicative of the different degrees of position in British court.
The Lilliputians are diminutive because they are of low moral character, suggesting the Whig politicians. On the other hand, the target of satire in Book II is immoral Englishmen, in contrast to abstract immorality. He also satirizes philosophers as he describes how he has to communicate his needs to the giants. After he conveys to his "Mistress" that he needs to relieve himself, for example, Gulliver apologizes to the "gentle Reader," but explains that what appears to be insignificant to him and others will "certainly help a Philosopher to enlarge his Thoughts and Imagination...." Here, then, is an example of the use of sarcasm in Swift's satire.
In Book III, Swift satirizes the inordinate love of reason of the Rationalists and Deists. As manifestation of their extreme rationalism, there is exaggeration in the Laputan abstract thinking that leads them nowhere other than disturbance. Gulliver observes,
...these People are under continual Disquietudes, never enjoying a Minute's Peace of Mind; and their Disturbances proceed from causes which very little affect the rest of Mortals.
In Book IV, Swift satirizes the vanity of people. For, Gulliver finds himself more content with the Houyhnhnms than with the petty Yahoos. But, Gulliver forgets that he is human, and upon returning to England, he goes to the stables and associates with the horses because his family smells like Yahoos to him. While Gulliver learns much, he is yet incapable of grasping the real depth of meaning of life; instead in his vanity,he has become too much of a philosopher whose perspective is distorted.