Gulliver feels neglected on Laputa, since the inhabitants seem interested only in mathematics and music and are far superior to him in their knowledge. He is bored by their conversation and wants to leave. There is one lord of the court whom Gulliver finds to be intelligent and curious, but who is regarded by the other inhabitants of Laputa as stupid because he has no ear for music. Gulliver asks this lord to petition the king to let him leave the island. The petition succeeds, and he is let down on the mountains above Lagado. He visits another lord, named Munodi, and is invited to stay at his home.
Gulliver and Munodi visit a nearby town, which Gulliver finds to be populated by poorly-dressed inhabitants living in shabby houses. The soil is badly cultivated and the people appear miserable. They then travel to Munodi’s country house, first passing many barren fields but then arriving in a lush green area that Munodi says belongs to his estate. He says that the other lords criticize him heavily for the “mismanagement” of his land.
Munodi explains that forty years ago some people went to Laputa and returned with new ideas about mathematics and art. They decided to establish an academy in Lagado to develop new theories on agriculture and construction and to initiate projects to improve the lives of the city’s inhabitants. However, the theories have never produced any results and the new techniques have left the country in ruin. He encourages Gulliver to visit the academy, which Gulliver is glad to do since he was once intrigued by projects of this sort himself.
Gulliver visits the academy, where he meets a man engaged in a project to extract sunbeams from cucumbers. He also meets a scientist trying to turn excrement back into food. Another is attempting to turn ice into gunpowder and is writing a treatise about the malleability of fire, hoping to have it published. An architect is designing a way to build houses from the roof down, and a blind master is teaching his blind apprentices to mix colors for painters according to smell and touch. An agronomist is designing a method of plowing fields with hogs by first burying food in the ground and then letting the hogs loose to dig it out. A doctor in another room tries to cure patients by blowing air through them. Gulliver leaves him trying to revive a dog that he has killed by supposedly curing it in this way.
On the other side of the academy there are people engaged in speculative learning. One professor has a class full of boys working from a machine that produces random sets of words. Using this machine, the teacher claims, anyone can write a book on philosophy or politics. A linguist in another room is attempting to remove all the elements of language except nouns. Such pruning, he claims, would make language more concise and prolong lives, since every word spoken is detrimental to the human body. Since nouns are only things, furthermore, it would be even easier to carry things and never speak at all. Another professor tries to teach mathematics by having his students eat wafers that have mathematical proofs written on them.
Gulliver then visits professors who are studying issues of government. One claims that women should be taxed according to their beauty and skill at dressing, and another claims that conspiracies against the government could be discovered by studying the excrement of subjects. Gulliver grows tired of the academy and begins to yearn for a return to England.
Gulliver tries to travel to Luggnagg, but he finds no ship available. Since he has to wait a month, he is advised to take a trip to Glubbdubdrib, the island of magicians. Gulliver visits the governor of Glubbdubdrib, and he finds that servants who appear and disappear like spirits attend the governor. The governor tells Gulliver that he has the power to call up any shade he would like. Gulliver chooses Alexander the Great, who assures him that he died not from poison but from excessive drinking. He then sees the Carthaginian general Hannibal and the Roman leaders Caesar, Pompey, and Brutus.
Gulliver sets apart one day to speak with the most venerated people in history, starting with Homer and Aristotle. He asks the French philosophers René Descartes and Pierre Gassendi to describe their systems to Aristotle, who freely acknowledges his own mistakes while pointing out that systems of nature will always vary from age to age.
Gulliver then returns to Luggnagg, where he is confined despite his desire to return to England. He is ordered to appear at the king’s court and is given lodging and an allowance. He learns that subjects are expected to lick the floor as they approach the king, and that the king sometimes gets rid of opponents in the court by coating the floor with poison.
The Luggnaggians tell Gulliver about certain immortal people, children born with a red spot on their foreheads who are called Struldbrugs. Gulliver devises a whole system of what he would do if he were immortal, starting with the acquisition of riches and knowledge. Contrary to his fantasy, however, he is told that after the age of thirty, most Struldbrugs grow sad and dejected, and by eighty, they are incapable of affection and envious of those who are able to die. If two of the Struldbrugs marry, the marriage is dissolved when one reaches eighty, because “those who are condemned without any fault of their own to a perpetual continuance in the world should not have their misery doubled by the load of a wife.” He meets some of these people and finds them to be unhappy and unpleasant, and he regrets ever wishing for their state.
Gulliver is finally able to depart from Luggnagg, after refusing employment there, and he arrives safely in Japan. From there he gains passage on a Dutch ship by pretending to be from Holland and sets sail from Amsterdam to England, where he finds his family in good health.
Swift continues his mockery of academia by describing the projects carried out in the cities below Laputa. The academy serves to create entirely useless projects while the people starve outside its walls. Each project described, such as the extraction of sunbeams from a cucumber, is not only impossibly flawed but also purposeless. Even if its scientific foundations were correct, it would still serve no real purpose for the people meant to gain from it. The result is a society in which science is promoted for no real reason and time is wasted as a matter of course.
Much of Swift’s inspiration for the scientists in this voyage came from the Royal Society of London for the Improving of Natural Knowledge, a scientific society founded in 1660 that had an important effect on the development of science in Europe. The prominent early scientists Robert Boyle, Robert Hooke, and Isaac Newton were all members of the Royal Society. All of them, but particularly Newton, were influential promoters of scientific theories that were at the heart of the Scientific Revolution. The Royal Society assigned itself the task of using the new techniques of science to improve the crafts, but it was far more successful at discovering natural phenomena than it was at building new, useful technologies. As a result, the Royal Society was open to the parody created by Swift, in which absentminded philosophers ruin a country by forcing its people to follow their novel and wholly useless methods. Interestingly, most of the experiments parodied by Swift had actually been proposed or carried out by British scientists at the time of his writing.
Glubbdubdrib offers the opportunity for Swift to satirize various historical figures, undermining their images as paragons of virtue or learning. Gulliver’s interaction with the dead hearkens back to Dante Alighieri’s fourteenth-century poem Inferno, in which Dante himself travels through the various regions of hell and witnesses sinners being punished. This imaginary tour of hell allowed Dante the author to skewer his political opponents and enemies, just as Swift’s imaginary wanderings allow him to ridicule certain aspects of society. Gulliver’s visit to Glubbdubdrib is part of Swift’s attempt in the third voyage to undercut standards of abstract learning. At the same time, however, Swift does elevate certain people above others. Generally speaking, the ancient Greeks and Romans are held up as truly virtuous, whereas the Europeans who have lived since are held up as somewhat degenerate.
The Struldbrugs of Luggnagg provide an opportunity for Swift to satirize human desires. Many would seek eternal life, and the primary benefit of old age, as Gulliver sees it, is the ability to use one’s accumulated wisdom to help humanity. The reality is much less glorious—instead of growing in wisdom, the immortal Struldbrugs grow only more prejudiced and selfish, eventually becoming a detriment to the whole Luggnaggian society. Furthermore, the Struldbrugs’ immense sadness despite their seeming advantage shows the emptiness of Gulliver’s desire—a desire prominent in Western society—to acquire riches. Swift denounces such self-absorbed goals as the province of small minds unconcerned with the good of society as a whole.