Quote: Perfection is round.
—Anne Carson, Red Doc>
Perfection is simplicity: As of 3rd September, the Quote throws up six results on Google, all of which are Carson’s citations. In today’s age that translates to: she said it first.
Three words, two ordinary nouns and the most frequent verb of the English language in its most frequent form. And it’s not nonsense.
Let’s start with the verb.
Even though “to be” is often used to equate and identify, simple sentences centring around it are not obviously semantically symmetric: round is perfection, means something else. Think: the circle, the sphere, the sun—often taken as symbols of the ideal, the perfect, the godly. In both the Quote and in round is perfection, the subject complement states a property of the subject. Indeed, perfection and round are—as Carson says of two utterly different things—parts of each other / although not parts of a / whole.
Therefore, is is a simple verb that can denote mutual inclusion without denoting equivalence.