The folly of theologians
Folly explains that no other group of people is so hesitant to acknowledge her services, despite being so thoroughly in her debt. These men protect themselves with "academic definitions, logical argumentations, inferential corollaries, explicit and implicit propositions" (57) but are arrogant, confusing, and misled. They prefer their own discourses to the scriptures, and mold the biblical text to fit their theses. They speak in an obnoxious manner intended to awe their listeners. They focus on minutiae and superfluities. Monks believe their adherence to strict rules means they are exemplars of the Christian faith. Popes and Bishops delight in their lives of luxury. Christ's message of simplicity is lost to these men. So strong are Erasmus's feelings on the theologians that it is through contemplation of them that Folly's tone begins to grow harsher and drop the light-heartedness that characterizes it in the beginning.
The necessity of folly for love, marriage, and friendship
Folly is necessary for all relationships on earth, particularly marriage and friendship. There would be so many more divorces if marriage was not eased by "flattery, jokes, yielding dispositions, mutual misunderstandings, dissimulations" (21). Husbands and wives are able to overlook each other's flaws and conceive of their spouse as ideal. Indeed, it would be difficult to have a child without the help of Folly. Friendship also benefits from her, for friends have to convince themselves that their friends' shortcomings are insignificant and their vices are their virtues. The fact that any human can find pleasure in another human's company, despite that human's great flaws and vices, is due to Folly. So by stressing her impact on these elements, Folly argues she is integrated into the most important aspects of human relationships.
Christianity and Folly
Most might assume Christianity is indebted more to wise men than to fools, but Erasmus writes that "the entire Christian religion seems to bear a certain natural affinity to folly, and relate far less clearly to wisdom" (82). Throughout the Bible, foolishness is spoken of approvingly, while wisdom is excoriated for being too closely part of the world. Examples can be found in Ecclesiastes, in the words of Paul and Christ, in Proverbs, in 2nd Corinthians, and more. Christ himself is the biggest fool of all because he took on the sin of all mankind and became sin itself. His word was carried throughout the world by his "ignorant, sottish disciples" (81) and his lesson was "nothing but folly and avoidance of wisdom" (81). Knowledge was proven to be dangerous even as early as Genesis, where Adam and Eve were instructed not to eat from the Tree of Knowledge. Happiness in Christ is close to madness, thus revealing the essential thesis of the speech's third section: Christianity welcomes, and is for, the fools and the ignorant. These arguments are very much responsible for what made Erasmus's work so controversial upon its publication.
Self-love and flattery
Both are commonly regarded in a negative light, but Folly demonstrates how they are beneficial to society. If a man does not love himself he will not be able to do anything that is "agreeable, gracious, [and] not in bad taste" (23). He has to flatter himself a bit before he can be esteemed by others. Philautia helps men appreciate their looks, intelligence, and position in the world. Flattery is self-love when applied to others, and is equally necessary. It "lifts dejected spirits, raises people out of the dumps, enlivens the languishing, animates the dull, heartens the sick, placates the angry, brings lovers together, and keeps them together" (46). It is a part of the admired art of eloquence and is the "honey and spice of all human intercourse" (46). Folly understands that pure honesty and truth can be dangerous and that flattery is helpful and even virtuous. Thus, both self-love and flattery help mankind live their lives, forget about their problems, and achieve great things. And so by default, Folly is responsible for encouraging those great things.
Delusion/Ignorance
Folly pleads her case that she makes mankind happier than wisdom can. Her argument is that man is happier when he does not realize the ugly truth of the world, and that a healthy dose of delusion can assist in that purpose. The calamities of the world are many, and only a helping of folly can mitigate them. The problems of old age can be ameliorated; Folly makes the old young again. She makes marriages and other relationships pleasant, brings amusement to gatherings, helps people forget their trials and tribulations, assists men in their creative endeavors, oils the wheels of society through flattery, and expels boredom and despair. The philosophers, who claim to know the mysteries of existence, are the most dour and discontented men. Wisdom does not bring contentment, whereas the happiest people on earth are the fools and the simpletons who are ignorant of fear, anger, depression, and death. Folly counsels her listeners to embrace ignorance.
The uselessness of philosophy
Philosophy, in The Praise of Folly, is revealed to be a useless and self-indulgent endeavor. It involves lofty claims to understanding nature, existence, essence, and God. Philosophers' ideas are never used to actually rule a commonwealth; the few historical examples proved to be disastrous. These men are the most odious in company, as they are unfit for mirth or pleasure. Overall, they are completely useless to other men, their families, and even themselves "because he knows nothing of everyday matters and exists on a completely different plane from that of common opinion and popular customs" (26). They spend their time patting each other on the back or tearing apart each other's conjectures. It is far better to be a fool or a simpleton than a philosopher, better to live one's life than it is contemplate it.
The ubiquity of folly
Folly is found everywhere; she lists various academic and social classes of men who rely upon folly for their accomplishments or who indulge in her offerings to gain fame and happiness. This life includes: doctors, lawyers, mystics, gamblers, hunters, philosophers, grammar teachers, businessmen, authors, poets, performers, lovers, doctors of theology, priests, monks, princes, courtiers, cardinals, bishops, and popes. She is found in marriages, friendships, and other relationships. Not only can "[we] find nothing either joyous or pleasant which doesn't owe a debt to [Folly]" (17) but almost no profession or endeavor is without her influence. Perhaps the best manifestation of this argument is that Folly ends up including every person or example as her domain by the end of the speech - the fools are foolish through behavior, while the 'wise' and the philosophical are foolish precisely because they do not embrace her despite their foolishness.
Rhetoric
Not only is Erasmus's work structured as a speech, but there are many explicit and implicit comments on oratory. Early on, Folly insists she will not use the common oratorical tricks, and yet ironically proceeds to use them nevertheless. As he over and over lambasts various figures for the way they speak or manipulate language for their own benefit, she is ironically doing that very thing, thereby reinforcing her argument that every aspect of our lives is representative of folly.
