Most university students take courses in the “liberal arts” without actually knowing what makes them liberal. The term, I learned long after graduating, comes from “free”—as in, free from having to work with the hands. A liberal education, in other words, is supposed to prepare young people to join the ranks of leadership. You could say it still attempts to do that, preparing the elites in every society; it just doesn’t do a very good job of it. A growing number of people question the liberal arts’ value; even academics seem to fail to agree on what this education is for, exactly.

For a solution, it makes sense to look at the original liberal arts: grammar, logic, rhetoric (the “Trivium,”), plus arithmetic, geometry, music, and astronomy. The mix may seem strange today. How could grammar and music teach leadership unless the student became a kindergarten principal or bandleader?

Rather than examine these subjects individually, we should view them in their entirety, put them in a modern context, and see what useful aptitudes we end up with. Over several months I boiled the subjects together and eventually came up with three essential modern aptitudes. Call them the New Trivium:

1. Grammar—Latin grammar, to be specific—held a place of honor in the original Trivium for good reason. It taught a student the essential structure of the world’s lingua franca, its common language, enabling him to associate at a high level with elites across wildly different nations and tribes. These days, a student should similarly learn the “grammar,” or human structure, of beliefs and traditions across cultures. In the broadest sense, the aptitude of Grammar encompasses languages, linguistics, the social sciences, history, literature—just about all of the aptly named humanities.

2. Arithmetic, geometry, and astronomy enable a student to gather, process and interpret data. I call this art “Decision Metrics.” Numbers, statistics, and data sets offer insights into the language of the cosmos; more practically, the student with a good grasp of data has a huge employment advantage over his competition. The so-called “hard” sciences as well as many of the social sciences, computer science, economics, and of course mathematics fall in this category.

3. Rhetoric, the art of persuasion, the art of leadership, deserves to stand alone as the third leg of the New Trivium. While Grammar reveals the beauty of language, Rhetoric coaxes words to make a living for themselves, persuading, changing reputations, reaping profits and winning elections. Rhetoric gives voice to all the other arts. Without it, the ancients said, we would have no civilization.

The New Trivium allows an intelligent student to give education a practical meaning, capturing the original purpose of the liberal arts. The good news is, Grammar and Decision Metrics would not require razing universities’ curriculum. The courses that teach these aptitudes already exist. As for Rhetoric… Ah, Rhetoric. Although increasing number of schools offer the art, few elite universities have yet to bother.

Those of us with an incomplete education need not despair. A reasonably intelligent adult could make up the gaps on her own. I can speak personally. My own formal education was limited to that first New Trivial aptitude, Grammar, or the humanities. I didn’t begin learning Decision Metrics until I became the manager of a group of technical journals in my twenties. Some years later, I became editorial director in charge of five newsstand magazines. I hired market researchers to help us sell more copies and subscriptions, and learned to love the beauty of numbers in the service of understanding markets—in other words, understanding groups of people.

As for Rhetoric, I failed to discover the art until my thirties, when I stumbled upon some rhetoric books in the stacks of a university library. My discovery led to a lifelong quest. I wrote two rhetorical books and am at work on a third. And I have taken on the mission of trying to convince elite American schools (including my own alma mater) to teach it.

Only when academics finally encompass the full scope of the liberal arts, including Grammar, Decision Metrics, and Rhetoric, can a liberal education truly call itself liberal. Or relevant.