During his stay in Luggnagg, Gulliver hears about the Struldbruggs, people in Luggnagg society who are immortal. Gulliver's first reaction to hearing about the Struldbruggs' immortality is one of envy and enthusiasm because it would allow a person to gain immense wealth, wisdom, and the philosophical serenity. He fantasizes what he might do if he were one. However, when an interpreter explains the reality of life as a Struldbrugg — that is they grow old, feeble, decaying, and forgetful — Gulliver's enthusiasm for a life of immortality disappears as quickly as it began.
In this chapter, Swift satirizes the theory that "experience is the best teacher." Already he has attacked all the other methods of gaining knowledge: Abstract reason was ridiculed in Laputa; pragmatic and scientific knowledge was his target in Balnibarbi; the humanities, and particularly history, suffered in Luggnagg. Now he discredits accumulated experience.
Like most people, Gulliver assumes that experience brings both wisdom and morality. He voices the human dream of immortality, sure that immortality will confer immense experience and, therefore, immense wisdom. Swift counters this naive dream of Gulliver's by presenting the Struldbruggs. It is true that they have immortality, but they do grow old. They wrinkle — and they degenerate; the physical is a symbol of the abstract once more. These creatures lack hope, kindness, generosity, affection, simplicity, honesty, and innocence.
When Swift's readers finish this chapter, they realize that Swift's theory is that reason is never to be exalted. People simply cannot depend on abstract, impersonal, inhuman reason. Nor can they depend on technological innovation, on history, or on the "modern" humane studies. The best guides are poetry and ancient philosophy.