Swift uses Gulliver's travels to the four strange and unique lands to reveal extremes of human behavior and fallacies. Each land offers a different look at some problematic aspect of human nature:
- Lilliput: The land of tiny, miniature Lilliputians represents the problems attached with over-zealous government and control. Here, Gulliver cannot help but feel superior to their unethical and strange ideas about government, children, and education.
- Brobdingnag: The tiny stature of the Lilliputians is immediately contrasted by the giant nature of the people of Brobdingnag; this is one direct way in which Swift builds upon the previous story. Where the Lilliputians are tiny over-zealous and controlling, the people of Brobdingnag really come across as Gulliver's superiors in many ways. Their system of politics and justice is much better than Gulliver's England.
- Part III: In his travels in Part III to Laputa, Balnibarbi, Glubbdubdrib, Luggnag, and Japan, Swift again examines another facet of the human condition, building on Gulliver's previous travels. Even though Gulliver swore never to travel again, his escapades in part three reveal a conviction against scientific or Enlightenment thinking and "new ideas over traditional, practical ways of doing things" ("Gulliver's Travels: Themes." eNotes).
- Houyhnhnm: Swift makes one final metaphor for human nature in the final stage of Gulliver's travels. When Gulliver arrives at Houyhnhnm land, Swift makes another contrasting comparison between the most elevated, logical people, the Houyhnhnms, and the lowest form that humanity can take, the yahoos.
Ultimately, the four sections of Gulliver's Travels do build upon one another by showing contrasts and contradictions to illustrate Swift's careful appraisal of the human condition.