Wood doesn't listen to classes during his one week off the road each month, only when he's behind the wheel.
Sometimes, the classes that involve math or obscure concepts such as string theory lose him. But not Dreyfus' class, which he finds electrifying.
He remembers being somewhere in western Kansas in April when he heard Dreyfus' concluding lecture on existentialism, during which the professor asked students to vote, by raising their hands, for their favorite philosophies.
Dreyfus offered a thumbnail description of each: traditional Christianity, with God the creator and heaven; Kierkegaard's unconditional commitment to another person or cause; Dostoevski's unconditional commitment to all human beings; Nietzsche's belief in different identities, a life more like a series of short stories than a novel.
Wood, who long ago broke away from his family's religion, voted for Nietzsche silently.
"OK, that's it," Dreyfus said. "I have to stop and hand out the evaluations."
The class erupted in a sustained ovation, whooping and whistling.
The course had been recorded a year earlier. But Wood, separated by space and time, clapped and whooped too.
"Big trucks have enormous inertia. They practically drive themselves," he said. The machine, indifferent to his emotions, powered on, his body molded to the wheel, his mind having a great ride.