(This post is inspired by teaching Classical Rhetoric this semester, particularly the kinds of questions that were brought up reading and discussing Robin Reames' The Ancient Art of Thinking for Yourself. My students really brought it this semester in that class, and I got a lot out of thinking alongside them).
Deleuze famously proclaims, in Nietzsche and Philosophy, that the purpose of philosophy is to harm stupidity. But, of course, this is Deleuze, so stupidity has a technical definition that he works out in several places, but mostly chapter three of Difference and Repetition, "The Image of Thought." Stupidity has nothing to do with error, or IQ, or nonsense. Rather, stupidity comes from a kind of cliched, unthinking. The sorts of "thought" that goes along with "as everybody knows," and "it goes without saying." While there are important differences, this certainly rhymes with Arendt's criticism of Eichmann as unthinking. The purpose of philosophy, then, is to produce concepts that manage to exist outside of the dominate image of thought, and create something new. Deleuze's understanding of stupidity is strange, because it assumes that thinking, rather than being something given and commonplace, must be made. And further, it is uncommon. Most of us are not thinking most of the time.
The idiot, briefly referenced in D&R, and made a full conceptual persona in What is Philosophy?. Etymologically the idiot is the private thinker, rather than one taking part of public affairs. As Wikipedia explains:
The word "idiot" ultimately comes from the Greek noun ἰδιώτης idiōtēs 'a private person, individual' (as opposed to the state), 'a private citizen' (as opposed to someone with a political office), 'a common man', 'a person lacking professional skill, layman', later 'unskilled', 'ignorant', derived from the adjective ἴδιος idios 'personal' (not public, not shared). In Latin, idiota was borrowed in the meaning 'uneducated', 'ignorant', 'common', and in Late Latin came to mean 'crude, illiterate, ignorant'. In French, it kept the meaning of 'illiterate', 'ignorant', and added the meaning 'stupid' in the 13th century. In English, it added the meaning 'mentally deficient' in the 14th century.
It shares the obvious cognates of idiom, idiosyncratic, idiopathic While it might seem that the idiot escapes stupidity because they avoid the public doxa of the image of thought, Deleuze is more ambiguous. Deleuze ties Descartes to the idiot, but sees him working within and replicating the image of thought. He opposed this to Dostoevsky's idiot. Some thinkers, particularly Stengers, has created even more positive models of the idiot against stupidity. But while Deleuze leaves open the possibility that stupidity can infect (for lack of a better verb) the idiot, he doesn't really explore how the opposite can be true. In other words, he doesn't explore how I kind of idiocy can produce stupidity.
For this, we need to perhaps broaden our definition of idiocy from a personal and private relationship to any kind of closed off conceptual group. Idiocy, in this sense, comes from an inability to share or understand the image of thought of another group. Rather than ever being one image of thought, we belong to many images at once. Because, as Deleuze well knows, each of us are many, so we belong to many images of thoughts at once. Many worlds, many places, many tropes. Idiocy comes from the inability to think and understand others, who have different values, terms, and goals than our own. Idiocy further implies an inability (perhaps even and unwillingness or a lack of realization) to communicate to people in these other worlds. So, just as stupidity can infect idiocy, idiocy can cause and create stupidity. That is, many cases of stupidity comes from people being unable to understand there are other ways of thinking, being, and valuing in this world. Indeed, if part of stupidity is the inability to have a thought from the outside, that outside must include other groups' thinking.
Deleuze, of course, famously hates communication. He tells us again and again some version that if anyone comes to the philosopher asking to debate, or have a conversation, the real philosopher runs away. He sees communication as as a kind of Universal set to build consensus, and thus, along with contemplation and reflection, are often confused with philosophy, but are the opposites or enemies of philosophical thinking (this is in lots of places, but mostly What is Philosophy?). This is understandable from the standpoint in which Deleuze was working, and that his real targets were of course the New Philosophers, and the particularly French obsession of putting philosophers (especially New Philosophers) on Television. But while I am sympathetic, he has this wrong.
While some communication scholars have posited that one can not *not* communicate, they seem to mean something like we are constantly putting out information into the world. That is not the same as communicating. Just as Deleuze understood that thinking was something that perhaps happened rarely, and that needed conditions for its happening, the same can be understood with communication. Communication, that is, the creating of a common, happens rarely, and it is something that must be actively made. The problem of idiocy is a problem of communication, and depends upon our inability to actually communicate. We think we are communicating with other people, but we truly understand only our own in-group. Those that understand the world definitely are not simply mistaken, but evil, alien, and barbarian. They are not understandable to us, and we are not understandable to them (in the US today, this can be most easily seen in our hyper political polarization).
In Aristotle's On Rhetoric (I, 2, 1358a), he tells us that rhetorical enthymemes (the kind of logical arguments particular to rhetoric, as opposed to the more formal syllogism of the dialectic) come from two different kinds of places. There are the topoi koinoi (common places, common topics) and the topoi idioi (the particular, or special, or private places and topics). So, the common place might be the ability to distinguish between the bigger and the smaller. The special places are the kinds of arguments that might make sense in physics or the law court, but not outside of them. Virno has a very interesting reading of Aristotle here (Grammar of the Multitude, 3.2). While I am mostly in agreement with Virno here, his reading here is incomplete. He sees the power of the special places, understood as a kind of expertise, as fading away. What remains is just the commonplaces, which form both a kind of danger and hope in Virno's analysis of the general intellect. But everywhere around is the particular places and topics are taking over. This is not the particular place of the law court of the physic's laboratory, but rather the particular places we get our news from, the topics we think of as important and valuable, and our ability to understand what is at stake in our decisions about the world. The topoi idioi are taking over the topoi koinoi.
Now, there are plenty of people (in all sorts of political orientations), who don't see any problems here. The diminishing power of rhetoric, argumentation, and persuasion is only finally revealing what they have long known to be true--politics is about power, especially power over one's enemies. Any appeal to civic virtues or common places has always been a lie by liberalism to hide the fundamental truth of political power, and using it. I want to be clear, this is a profoundly stupid position, and one that demands the stupid loyalty of others. This is why Ranciere tells us in Disagreement that "politics is not made up of power relationships; it is made up of relationships between worlds" (p. 42). Rather what we need now more than ever is rhetoric, argumentation, and persuasion (one might say simply communication). These fields are made for the creation of the common, with their attempts as audience analysis, stasis theory, identification, and other tools that are made to create, however temporarily, a common. Theses commons are not the grounds of consensus, but the ground necessary for disagreement, debate, agonism, and dissensus to take place. It is an alternative to power, and one that is sorely needed. Philsophy and rhetoric are not the same things, but they are here allied forces. If the purpose of philosophy is to harm stupidity, than the purpose of rhetoric is to harm idiocy.