One of the most interesting questions about Gullivers Travels is whether the Houyhnhnms represent an ideal of rationality or whether on the other hand they are the butt of Swift's satire. In other words, in Book IV, is Swift poking fun at the talking horses or does he intend for us to take them seriously as the proper way to act? If we look closely at the way that the Houyhnhnms act, we can see that in fact Swift does not take them seriously: he uses them to show the dangers of pride.
First we have to see that Swift does not even take Gullver seriously. For instance, his name sounds much like gullible, which suggests that he will believe anything. Also, when he first sees the Yahoos and they throw excrement on him, he responds by doing the same in return until they run away. He says, "I must needs discover some more rational being," even though as a human he is already the most rational being there is. This is why Swift refers to Erasmus Darwins discovery of the origin of the species and the voyage of the Beagle-to show how Gulliver knows that people are at the top of the food chain. But if Lemule Gulliver is satirized, so are the Houyhnhnms, whose voices sound like the call of castrati. They walk on two legs instead of four, and seem to be much like people. As Gulliver says, "It was with the utmost astonishment that I witnessed these creatures playing the flute and dancing a Vienese waltz. To my mind, they seemed like the greatest humans ever seen in court, even more dextrous than the Lord Edmund Burke" . As this quote demonstrates, Gulliver is terribly impressed, but his admiration for the Houyhnhnms is short-lived because they are so prideful. For instance, the leader of the Houyhnhnms claims that he has read all the works of Charles Dickens, and that he can singlehandedly recite the names of all the Kings and Queens of England up to George II. Swift subtly shows that this Houyhnhnms pride is misplaced when, in the middle of the intellectual competition, he forgets the name of Queen Elizabeths husband.
Swifts satire of the Houyhnhnms comes out in other ways as well. One of the most memorable scenes is when the dapple grey mare attempts to woo the horse that Guenivre has brought with him to the island. First she acts flirtatiously, parading around the bewildered horse. But when this does not have the desired effect, she gets another idea: "As I watched in amazement from my perch in the top of a tree, the sorrel nag dashed off and returned with a yahoo on her back who was yet more monstrous than Mr. Pope being fitted by a clothier. She dropped this creature before my nag as if offering up a sacrifice. My horse sniffed the creature and turned away." It might seem that we should take this scene seriously as a failed attempt at courtship, and that consequently we should see the grey mare as an unrequited lover. But it makes more sense if we see that Swift is being satiric here: it is the female Houyhnhnm who makes the move, which would not have happened in eighteenth-century England. The Houyhnhm is being prideful, and it is that pride that makes him unable to impress Gullivers horse. Gulliver imagines the horse saying, Sblood, the notion of creating the bare backed beast with an animal who had held Mr. Pope on her back makes me queezy .
A final indication that the Houyhnmns are not meant to be taken seriously occurs when the leader of the Houynhms visits Lilliput, where he visits the French Royal Society. He goes into a room in which a scientist is trying to turn wine into water (itself a prideful act that refers to the marriage at Gallilee). The scientist has been working hard at the experiment for many years without success, when the Houyhnmn arrives and immediately knows that to do: "The creature no sooner stepped through the doorway than he struck upon a plan. Slurping up all the wine in sight, he quickly made water in a bucket that sat near the door" .
He has accomplished the scientists goal, but the scientist is not happy, for his livelihood has now been destroyed. Swifts clear implication is that even though the Houyhnhmns are smart, they do not know how to use that knowledge for the benefit of society, only for their own prideful agrandizement.
Throughout Gullivers Travels, the Houyhnhms are shown to be an ideal gone wrong. Though their intent might have been good, they don't know how to do what they want to do because they are filled with pride. They mislead Gulliver and they even mislead themselves. The satire on them is particularly well explained by the new born Houyhnhm who, having just been born, exclaims, "With this sort of entrance, what must I expect from the rest of my life!" .