Gulliver's Travels has been the recipient of several designations: from Menippean satire to a children's story, from proto-Science Fiction to a forerunner of the modern novel.
Published seven years after Daniel Defoe's wildly successful Robinson Crusoe, Gulliver's Travels may be read as a systematic rebuttal of Defoe's optimistic account of human capability. In The Unthinkable Swift: The Spontaneous Philosophy of a Church of England Man, Warren Montag argues that Swift was concerned to refute the notion that the individual precedes society, as Defoe's novel seems to suggest. Swift regarded such thought as a dangerous endorsement of Thomas Hobbes' radical political philosophy and for this reason Gulliver repeatedly encounters established societies rather than desolate islands. The captain who invites Gulliver to serve as a surgeon aboard his ship on the disastrous third voyage is named Robinson.
Scholar Allan Bloom points out that Swift's critique of science (the experiments of Laputa) is the first such questioning by a modern liberal democrat of the effects and cost on a society which embraces and celebrates policies pursuing scientific progress.
A possible reason for the book's classic status is that it can be seen as many things to many different people. Broadly, the book has three themes:
- A satirical view of the state of European government, and of petty differences between religions
- An inquiry into whether men are inherently corrupt or whether they become corrupted
- A restatement of the older "ancients versus moderns" controversy previously addressed by Swift in The Battle of the Books
In terms of storytelling and construction the parts follow a pattern:
- The causes of Gulliver's misadventures become more malignant as time goes on—he is first shipwrecked, then abandoned, then attacked by strangers, then attacked by his own crew.
- Gulliver's attitude hardens as the book progresses—he is genuinely surprised by the viciousness and politicking of the Lilliputians but finds the behaviour of the Yahoos in the fourth part reflective of the behaviour of people.
- Each part is the reverse of the preceding part—Gulliver is big/small/wise/ignorant, the countries are complex/simple/scientific/natural, and the forms of government are worse/better/worse/better than England's.
- Gulliver's viewpoint between parts is mirrored by that of his antagonists in the contrasting part—Gulliver sees the tiny Lilliputians as being vicious and unscrupulous, and then the king of Brobdingnag sees Europe in exactly the same light; Gulliver sees the Laputians as unreasonable, and his Houyhnhnm master sees humanity as equally so.
- No form of government is ideal—the simplistic Brobdingnagians enjoy public executions and have streets infested with beggars, the honest and upright Houyhnhnms who have no word for lying are happy to suppress the true nature of Gulliver as a Yahoo and are equally unconcerned about his reaction to being expelled.
- Specific individuals may be good even where the race is bad—Gulliver finds a friend in each of his travels and, despite Gulliver's rejection and horror toward all Yahoos, is treated very well by the Portuguese captain, Don Pedro, who returns him to England at the novel's end.
Of equal interest is the character of Gulliver himself—he progresses from a cheery optimist at the start of the first part to the pompous misanthrope of the book's conclusion and we may well have to filter our understanding of the work if we are to believe the final misanthrope wrote the whole work. In this sense Gulliver's Travels is a very modern and complex novel. There are subtle shifts throughout the book, such as when Gulliver begins to see all humans, not just those in Houyhnhnm-land, as Yahoos.
Throughout, Gulliver is presented as being gullible; he believes what he is told, never perceives deeper meanings, is an honest man, and expects others to be honest. This makes for fun and irony; what Gulliver says can be trusted to be accurate, and he does not always understand the meaning of what he perceives.
Also, although Gulliver is presented as a commonplace "everyman", lacking higher education, he possesses a remarkable natural gift for language. He quickly becomes fluent in the native tongue of any strange land in which he finds himself, a literary device that adds much understanding and humour to Swift's work.
Despite the depth and subtlety of the book, it is often classified as a children's story because of the popularity of the Lilliput section (frequently bowdlerised) as a book for children. One can still buy books entitled Gulliver's Travels which contain only parts of the Lilliput voyage.
Pedro de Mendez is the name of the Portuguese captain who rescues Gulliver in Book IV. When Gulliver is forced to leave the Island of the Houyhnhnms, his plan is "to discover some small Island uninhabited" where he can live in solitude. Instead, he is picked up by Don Pedro's crew. Despite Gulliver's appearance—he is dressed in skins and speaks like a horse—Don Pedro treats him compassionately and returns him to Lisbon.
Though Don Pedro appears only briefly, he has become an important figure in the debate between so-called soft school and hard school readers of Gulliver's Travels. Soft school critics contend that Gulliver is a target of Swift's satire and that Don Pedro represents an ideal of human kindness and generosity. For hard-school critics, Gulliver sees the bleak fallenness at the center of human nature, and Don Pedro is merely a minor character who, in Gulliver's words, is "an Animal which had some little Portion of Reason."