Lord Munodi is the one sensible man in all of Laputa. You know that saying, "in the land of the blind, the one-eyed man is king"? Lord Munodi is proof that that is not true: in the land of the blind, the one-eyed man is mocked and hated. Lord Munodi belongs to an extremely important family with a large estate on Balnibarbi, which is the only thing that keeps him from being totally thrown out of Laputa. He is despised by the King and his court for not adopting new and experimental modes of managing his family estates along with everyone else.
See, the thing is, about 40 years before Gulliver arrives, all of Balnibarbi was green and fruitful. But then, a couple of Balnibarbians went up to Laputa, where they learned about the abstract equations the Laputians love. These Balnibarbians came back down with all kinds of new ideas for improving buildings and cultivating fields, all of which, without exception, are disasters. But that hasn't prevented anyone from trying and trying again. They're all caught up in a fad for "reform," and think Lord Munodi is a backwards fool for not adopting the new ways.
Lord Munodi's good sense and old-fashioned ways make him an excellent companion for Gulliver. It is Lord Munodi who manages to get a guide for Gulliver through the Royal Academy in Lagado, much to Gulliver's interest.