In the opening of his book Don Quixote, Cervantes claims that Don Quixote goes mad after reading too many novels about the heroic deeds of knights-errant. However, like the old argument of whether the chicken or the age came first, it could be argued that Quixote was going mad and latched onto these books, which he then incorporated into his madness. If this is the case, the problem was within Quixote himself, and if he hadn't built a grand delusion around stories about knights, he would have developed some other paranoid delusion to act out.
As the author says in the first chapter, " ... whenever [Quixote] was at leisure ... [he] gave himself up to reading books of chivalry with such ardour and avidity that he almost entirely neglected the ... management of his property; and to such a pitch did his eagerness and infatuation go that he sold many an acre of tillageland to buy books of chivalry to read, and brought home as many of them as he could get." (Part I, Chapter 1)
The story at first glance seems charming. Don Quixote decides that he must ride off to avenge wrong-doing and to exalt the Lady Dulcinea. The story has been retold in various forms including the musical Man of La Mancha, which portrays Don Quixote as a deluded but gentle and well-meaning old man whose dreams improve those around him. The actual story written by Cervantes is not quite so simple.
And, in fact, his delusions do seem harmless to anyone but him at first. He decides that a poor, dirty peasant woman is actually a fine lady of breeding, and that all the heroic deeds he does, he will do to honor her. However, by chapter 4 we see that Quixote's meddlesome delusions may not always be helpful. He comes upon a young boy being mercilessly beaten by his master. The boy says his master owes him money; the master says the boy is dishonest. Don Quixote decides arbitrarily that the boy is telling the truth, and insists that the man stop beating the boy and give him the money. The man, realizing Quixote will leave if he humors him, promises to do so. As soon as Quixote is gone, he begins beating the boy. This incident is characteristic of many of Quixote's adventures in the book: he sees the events one way, and everyone else sees them as something quite different. Sometimes only Quixote is hurt by these delusions, but sometimes his "squire" Sancho gets badly beaten, and in one incident, Quixote's horse is badly hurt. In fact, Don Quixote marches through the world looking for opportunities to demand that he be treated as a markedly special person, or picking fights. If the books he had read caused this behavior, then the books would have done him great harm. If Don Quixote had behaved as he is sometimes portrayed, a simple man simply trying to improve the world, then the books would have done him good. But since tales of knights were quite popular at the time, but very few men then imagined themselves to be knights, it seems more likely that as Don Quixote slipped into paranoia, he structured his system of false beliefs around the books he was reading at the time. This isn't much different than the people in the fifties who were certain that people Mars were trying to contact them through the fillings in their teeth. Scientists were speculating about whether or not there could be intelligent life on Mars, and people with a tenuous grip on reality latched on to that idea, decided it was true, and that they were so special that the Martians were trying to communicate with them.
The longer Don Quixote acts out his fantasy, the more real it becomes to him. His armor is made out of discarded rubbish, but to him it is real. His horse is old and tired, but to Don Quixote it is an beautiful, strong steed that in its own way is as heroic as Don Quixote is. By chapter 25 of the first book, Don Quixote's delusions are solidly in place, and it seems that nothing will dissuade him. In rich irony, Don Quixote decides that he is obligated to go mad because his beloved Dulcinea has been unfaithful. Sancho tries to reason with the Don, pointing out that he could not possibly know this to be true. Quixote responds that if he imagines it, what he imagines is more important than what might actually have happened. When Sancho realizes that Dulcinea is just a peasant woman, and not of royalty, Quixote informs him that since he, Quixote, has decided she is a princess, then she is one. He explains how solidly he holds his beliefs: "I thank thee for thy good intentions, friend Sancho ... But I would have thee know that all these things I am doing are not in joke, but very much in earnest, for anything else would be a transgression of the ordinances of chivalry, which forbid us to tell any lie whatever under the penalties due to apostasy...'" (Part I, Chapter 25).
The people who care about Don Quixote become more and more concerned about him as he descends more and more deeply into his delusions. One young man, a student by the name of Sampson Carrasco, is sure he can end Don Quixote's delusions. He dresses up as a knight. Calling himself the "Knight of the Mirrors," he engages Don Quixote in battle. By a fluke Quixote wins the encounter, a victory he dedicates to Dulcinea and which convinces him more than ever that he is a knight -- or else why would another knight challenge him? He also encounters another man with a similar delusion, including having a squire. The four of them reinforce each others' stories. Nothing, it seems, can bring Don Quixote back to reality. His notions, formed out of the books he has read and used to give his madness shape and form, have now been reinforced by two other men claiming to be knights. His utter belief that he is actually a knight will be his undoing.
Carrasco tries again, this time as the "Knight of the Full Moon." He approaches Don Quixote dressed in his barber's bowl for a helmet and his "suit of armor," and challenges him to a duel. Carrasco had no trouble figuring out how to fit into Quixote's delusion; all he had to do was read the books the Don had read. Carrasco challenges Quixote to the duel. The purpose of the duel is to determine whether the lady Carrasco honors or the lady Quixote honors is more beautiful. If Carrasco loses, he will acknowledge Dulcinea as the most beautiful and virtuous woman in all Christendom. However, if Quixote loses, he must return to his village, a beaten man. As Carrasco explains it to someone else, " ... As he is so scrupulous in his observance of the laws of knight-errantry, he will, no doubt, in order to keep his word, obey the injunction I have laid upon him. This, senor, is how the matter stands, and I have nothing more to tell you. I implore of you not to betray me, or tell Don Quixote who I am; so that my honest endeavours may be successful, and that a man of excellent wits- were he only rid of the fooleries of chivalry- may get them back again." (Book II, Chapter 65).
This time Don Quixote does lose. He does the only thing he can, and returns to his village, where his niece and his housekeeper have burned the books he loved so. As he enters the village, her sees two boys wrestling. As they fight, he…