Change is coming to higher education, and probably sooner than we expect. Those of us who love the liberal arts must either speak out and find ways to demonstrate our value to the wider world, or accept that others will redefine higher education for us, against our will.

The pressures for change are obvious. For decades, tuition has been rising faster than inflation. A college degree is increasingly seen as the necessary ticket to entry into the middle class, while college tuition has become increasingly unaffordable for the middle class.

Meanwhile, the rise of digital technologies has been driving down the cost of information to almost nothing. Vast digital libraries already are available for free online, and now some colleges are moving to provide ever more of their content online, for free, or at little cost.

When information is so cheap, why is a college education so expensive?

Fancy buildings and a proliferation of administrators explain part of the recent rise in costs, but the major cost is the faculty. We teach similar numbers of students from year to year, and our methods would not be unfamiliar to our medieval antecedents. We don’t in any obvious way get more efficient from year to year, and as efficiency gains drive down prices in the rest of the economy, the traditional approach to education becomes relatively ever more expensive.

Either we professors will find a way to demonstrate to outsiders that they should value our teaching and scholarship as we do, or we will be judged by the values of others.

Facing obvious pressure to spend his state’s tax revenues efficiently, Florida Gov. Rick Scott is considering a proposal to charge students less for majoring in “high-skill, high-wage, high-demand” subjects and more in other fields. While no final determination has been made, it appears that all the “high-skill” and “high-wage” majors are in the natural and applied sciences, and the other majors — presumably low-skill and low-wage majors — are in the social sciences and humanities.

Scott’s measure of value is simple and obvious: economic return on investment. In his view, the professors and fields that produce measurable economic returns are valuable and should be encouraged; the others, discouraged.

We humanists might accept Scott’s standard of value and look more closely at the data, to see whether the evidence shows that those who are more liberally educated, or at least whether those who are well educated in the liberal arts, perhaps do make more money over a lifetime than those whose education is more scientific and technical.

According to one recent study produced by Georgetown University’s Center for Education and the Work-force, life and natural science graduates as a group are more likely to be employed than humanities and liberal arts graduates. I suspect that students who are truly well educated in the humanities and liberal arts — those who emerge from our classes as “high-skill” — will be found to do just as well, economically, as their “high-skill” science counterparts.

If we humanists and social scientists are ever to win that argument, we will have to develop robust, reliable and trustworthy measures of the skills we believe we are imparting to our students. Grades, alas, are no longer that measure. Rather than resist the effort to devise measures of skill and knowledge that outsiders will trust, we professors must take the lead.

We also can fight Scott’s premise and demonstrate that not all value is economic.

Humanists used to argue that their task was to preserve and transmit to the future a common cultural inheritance, to prepare and ennoble citizens by forging a shared intellectual culture. It used to be thought that every educated person knew well Shakespeare and the Bible, and a few other core texts that provided a rich store of shared lessons and stories that helped knit together the diverse strands of our people.

Humanists also used to argue that they taught students the best of what was thought and said, that a liberal education is a worthy adornment of the mind and elevation of the soul, apart from any utilitarian value.

I think that the liberal arts, thus understood, would readily demonstrate their value to a skeptical world.

As long as we professors insist on ignoring our critics or just replying with an answer that amounts to “Trust us: We teach critical thinking and writing,” outside constituencies will continue to reply: “Prove it.”

Joseph R. Reisert is associate professor of American constitutional law and chairman of the department of government at Colby College in Waterville.