Virgil was the guy who came up with the words on Jean McCarthy's small marker, "mens agitat molem." Taken literally from the Latin it means "the mind moves the masses" or "the mind moves matter." Taken in the broader context of Virgil's Aenead, specifically book VI, "The Transmigration of Souls," it has to do with the Creation. One translation states it as "mind ignites life" in a grand sweeping verse on the circle of life.
So it turns out our friend Jean was possibly a deep thinker. Either that or she went to the University of Oregon. It's their motto.
I'm betting on the former.