English Society Exposed in Gulliver's Travels
In Gulliver's Travels, Swift takes us to many places that serve as a looking glass for the foibles of English society, but none of the places are as severe a censure of men as Houyhnhnmland. Here Swift has made a clear division of pure reason, embodied in the Houyhnhnms (maybe he was refering to "horse sense"), and raw passion, embodied in the Yahoos (which are "coincidentally" very manlike). Here Gulliver has to make the choice between Houyhnhnms and Yahoos, reason and passion. He initially rejects the Yahoos because of their repulsiveness to him, but at the same time he doesn't embrace the Houyhnhnms either. He still wants to cling in many ways to his English heritage, but his discussions with his master proves to himself, despite his asserted differences, that he and his English society are really Yahoo!
When I thought of my family, my friends, my countrymen, or human race in general, I considered them as they really were, Yahoos in shape and disposition, perhaps a little more civilized, and qualified with the gift of speech; but making no other use of reason than to improve and multiply those vices, whereof their brethren in this country had only the share that nature allotted them.
Thus Gulliver is faced with this decision again between Houyhnhnm and Yahoo, but now he sees Yahoo as being himself and country. He decides to reject Yahoos and his former self and embrace Houyhnhnms and reason. I believe chapter ten to be the crucial chapter in the book, because Gulliver decides to abandon all things "Yahoo," and in the same chapter Houyhnhnms and reason decide to reject Gulliver.
In the beginning of chapter ten, Gulliver relates his happy lodgings next to his master's house, which includes the account of what he has done for shoes,
I soled my shoes...and fitted to the upper leather, and when this was worn out, I supplied it with the skins of Yahoos, dried in the sun.
This fact is horrific if one considers that Gulliver identifies himself with Yahoos. It is a clear attempt to raise himself beyond the lowliness of Yahoos, but at the same time shows his true Yahooness, that he would use the skins of his own kind for his benefit. Even Houyhnhnms don't use the skins of Yahoos for anything, but maybe Swift is suggesting that one can't escape their nature.
Gulliver goes on to express his great gladness for being in Houyhnhnmland and not England, which at the same time allows Swift an oppurtunity to give one of his strongest censures of English society in an explosive rant (like Swift is noted for).
I enjoyed perfect health of body, and tranquility of mind; I did not feel the treachery or inconstancy of a friend, nor the inquiries of a secret or open enemy. I had no occasion of bribing, flattering, or pimping to procure the favor of any great man, or of his minion. I wanted no fence against fraud or oppression; here was neither physician to...