They make it seem like deep thinking is going on, but it isn’t.

WSJ, By Stephen Miller, Oct. 14, 2019 6:53 pm ET

What are “qualia”? I stumbled on the word recently in the Times Literary Supplement, where a review of novels by Neal Stephenson and Don DeLillo observed that both authors “are much concerned with qualia.” I looked up “quale,” the singular, in the Oxford English Dictionary, which defines it as “the property or quality of a thing; Philosophy a quality or property as perceived or experienced by a person; (also) a thing having certain qualities.”

This definition is as clear as mud. Does quale refer to something objective or to something subjective?

The OED gives 11 examples of how quale or qualia have been used, the first dating from 1654. Here are two recent examples. Philosopher A.J. Ayer: “So far as anything can be, qualia are pre-theoretical.” I have no idea what pre-theoretical means. The second is from an essay in the Philosophical Quarterly: “It is possible to hold that certain properties of certain mental states, namely those I’ve called qualia, are such that their possession or absence makes no difference to the physical world.”

The sentences suggest that quale refers to a subjective experience, which is what the philosopher Daniel Dennett says: Qualia is “an unfamiliar term for something that could not be more familiar to each of us: the ways things seem to us.”

I get it! Just as Monsieur Jourdain in Molière’s “Le Bourgeois Gentilhomme” is surprised to learn that he is speaking prose, so I am surprised to learn that my daily life is filled with qualia.

Quale and qualia are what I would call “fuzzy profound” words or phrases. They give the appearance that deep thinking is going on, but usually it isn’t.

Contemporary intellectual life, Saul Bellow implies in “Herzog” (1964), is filled with fuzzy-profound terms. Herzog writes to Martin Heidegger: “I should like to know what you mean by the expression ‘the fall into the quotidian.’ When did this fall occur? Where were we standing when it happened?”

I should like to write the TLS reviewer: “Aren’t all novels concerned with qualia—with the characters’ subjective view of things?”

When I was in college more than half a century ago, there were two popular fuzzy-profound words: “dialectical” and “existential.” Later, “postmodern” and “hermeneutical” became popular. Perhaps the best-known fuzzy-profound word is “modernity.” The OED’s second definition is “an intellectual tendency or social perspective characterized by departure from or repudiation of traditional ideas, doctrines, and cultural values in favour of contemporary or radical values and beliefs (chiefly those of scientific rationalism and liberalism).”

For some observers, modernity started with Machiavelli; for others, with the Enlightenment or the rise of capitalism or the Industrial Revolution or World War I. Some writers deem the present “late modernity”—and also, believe it or not, “liquid modernity.”

To be sure, writers I admire use the word modernity. The Polish philosopher Leszek Kolakowski wrote a book titled “Modernity on Endless Trial.” But the word is so fuzzy that writers should avoid it. Modernity shares with quale the property of obscuring more than it illuminates.

Mr. Miller is author of “Walking New York: Reflections of American Writers From Walt Whitman to Teju Cole.”