LitCharts assigns a color and icon to each theme in Gulliver's Travels, which you can use to track the themes throughout the work.
Perspective
Moral vs. Physical Power
Society and the State
Knowledge
Truth and Deception
Summary
Analysis
Gulliver sets aside a day to see the ghosts of men renowned for their knowledge. He sees Homer and Aristotle and their huge crowd of commentators, none of whom Homer and Aristotle have met since the commentators are so ashamed by the gross lies they’ve made up in their commentaries that they’ve avoided Homer and Aristotle in the afterlife.
This anecdote intertwines the themes of knowledge and deception—some of history’s most “knowledgeable” scholars (the commentators) are exposed as shameful liars.
Gulliver calls up Descartes and Gassendi to school Aristotle in their systems. Aristotle freely admits his own errors. Still, he says that new theories of nature go in and out of fashion and even those that purport to be grounded in timeless mathematic principles will vary age to age. Gulliver also calls up the Roman emperors.
Gulliver arranges the meeting between these philosophers to establish absolute truth by showing Aristotle his own theories were lies. However, Aristotle wisely recognizes that absolute truth does not exist—truth is just a matter of people’s perspectives at a particular time.
Gulliver then calls up the modern deceased and meets the royalty and aristocracy of Europe, in all of whom he can detect tainted and degenerate blood brought into the bloodline by men of low standing. By conversing with these royals and aristocrats, Gulliver discovers how dishonest the accounts of history are that portray these people as grand and virtuous when really they are weaklings, commoners, villains, hypocrites, liars, and corrupt people. He calls historians “prostitute writers.” The kings insist that virtue is just “a perpetual clog to public business” and that the throne relies on “corruption.”
Gulliver’s encounter with the past rulers of European states makes him realize that all the historical knowledge he possesses has come from deceptive sources—the “prostitute” historians who represented the rulers as morally and physically powerful men. Yet these rulers, Gulliver finds, were in fact weak on both counts: they are corrupt and their bodies are physically debased by polluted bloodlines. Gulliver’s perspective on history shifts.
Continuing in this conversation, Gulliver learns that all of history’s good statesmen and virtuous leaders are remembered as traitorous villains. Gulliver reflects that, just like it happened in Rome, Europe’s acquisition of wealth has lead its people to be less healthy and more corrupt, and the past century has reduced England to a state of disgusting degeneracy.
Gulliver’s reflection links societal wealth with societal corruption. The text is thus implicitly advocating a simpler lifestyle as a path to virtue.