Actor-turned-author Tom Hanks addressed Harvard University graduates in a commencement speech in which he spoke about the importance of truth, the Associated Press reports.

Hanks, known for his roles in Hollywood blockbusters including Forrest Gump, Sleepless in Seattle, and Saving Private Ryan, received an honorary doctor of arts degree from the university. The honor came less than three weeks after the publication of his debut novel, The Making of Another Major Motion Picture Masterpiece, which a critic for Kirkus called “a loose-limbed, bighearted Hollywood yarn.” Hanks is also the author of a 2017 story collection, Uncommon Type.

Hanks told the graduates that for some people, truth is “no longer based on data, nor common sense, nor even common decency.

“Telling the truth is no longer the benchmark for public service,” the actor said. “It’s no longer the salve to our fears, or the guide to our actions. Truth is now considered malleable, by opinion and by zero sum endgames.…The truth, the truth is sacred. Unalterable. Chiseled into the stone and the foundation of our republic.”

Hanks took a self-deprecating turn and referenced his performances in films based on Dan Brown’s The Da Vinci Code and other novels about Robert Langdon, a fictional Harvard professor of “symbology.” (That academic discipline does not exist, at Harvard or elsewhere.)

“Now, without having done a lick of work, without having spent any time in class, without once walking into that library—in order to have anything to do with the graduating class of Harvard, its faculty, or its distinguished alumni—I make a damn good living playing someone who did,” he said. “It’s the way of the world, kids.”

Michael Schaub, a journalist and regular contributor to NPR, lives near Austin, Texas.