The education scholar Walter C. Parker sought to invoke this original meaning in his 2005 essay “Teaching Against Idiocy.” In it, he writes that “when a person’s behavior became idiotic — concerned myopically with private things and unmindful of common things — then the person was believed to be like a rudderless ship, without consequence save for the danger it posed to others.” The idiot, then, was a threat to the city-state, to public life, and to the bonds that make communication and community possible. Parker continues: “An idiot is suicidal in a certain way, definitely self-defeating, for the idiot does not know that privacy and individual autonomy are entirely dependent on the community.” Parker also notes that the idiot has not yet reached “puberty,” or the transition to public life.

The idiot, understood in this sense, undermines not only community but also communication. An “idiom” is a phrase peculiar to a specific language or place. The idiot speaks only in idioms, though these function for him not as colorful additions to a language or culture, but are understood by him alone. To members of the community, his utterances are the babblings of a baby or a madman, full of sound and fury, signifying nothing.

Given all this, the idiot can be defined as such: a prepubescent, parasitic solipsist who talks only to himself.

In the mid-19th and early 20th centuries, the term began to take on the more familiar meaning, namely a person of low intelligence. This meaning is fraught with ableist history, as “idiot” was used as a diagnostic term indicating severe intellectual or developmental disability. Dr. Henry H. Goddard was the first to translate the French Binet-Simon intelligence test, a precursor to I.Q. tests, into English, and used the metric to classify “mental age”: An adult with a mental age less than 3 years old was labeled an “idiot”; between 3 and 7, an “imbecile”; and between 7 and 10, a “moron.” Originally, an I.Q. was determined by dividing mental age by actual age and multiplying by 100: An idiot was anyone with an I.Q. below 30. (Goddard, by the way, was an early advocate for special education but also favored eugenic practices and believed that the idiot should be removed from society by institutionalization or sterilization.)

Thankfully, such medical nomenclature has fallen out of favor. Yet, the term is still on the books in Kentucky, Mississippi, New Mexico and Ohio, which officially do not allow “idiots” to vote.