Comedian Bill Maher urged free thinking and reflected on the meaning of liberalism in his address at UC Berkeley’s Saturday commencement, while several students in the audience held up signs criticizing the comedian for his controversial remarks on religion.

In his speech, Maher highlighted environmental issues and cited his desire to “make a difference” as his inspiration for being liberal, decrying oppression and making jokes about Republicans. The announcement of Maher as this year’s speaker sparked significant protest, as some students argued that commencement would be marred by honoring someone whose comments had made certain campus communities feel alienated.

Although he did not directly address this controversy during his speech, Maher praised the campus for inviting him in what he described as a statement in line with the 50th anniversary of the Free Speech Movement.

“Never forget that we are lucky to live in a country that has a First Amendment,” Maher said. “Liberals should want to own it the way conservatives own the Second.”

Maher hosts “Real Time with Bill Maher” on HBO, where he has criticized religion — particularly Islam. In an October segment, he called Islam “the only religion that acts like the Mafia.”

In his speech, Maher referred to post-graduation life as the beginning of a “second life,” as graduates become “infants in the adult world.” He expressed optimism about the state of human progress but highlighted the looming threat of climate change.

“I was born after electricity, after antibiotics and, thank you Jesus, especially after indoor toilets. I was born after those things, but I was born before climate change and environmental destruction could make life on earth a living hell,” Maher said. “Unless we solve that issue, there are no other issues.”

Laney Burke, a graduating senior, said she thought Maher addressed the controversy around his invitation in a humorous way. Greg Zoumaras, also a graduating senior, praised Maher’s focus on environmental issues and free thinking.

“I think the university did a good job inviting him and supporting him,” Zoumaras said.

But UC Berkeley graduating senior Reem Altuwayjiri said she was surprised at the campus’s decision to invite Maher in light of his harsh criticism of Islam. Although she thought Maher’s speech itself was good, Altuwayjiri said she “wasn’t so happy that he was here.”

Prior to the ceremony, some students distributed flyers criticizing Maher and held up signs reading, “Dear Admin don’t Maher our commencement” during the keynote speech. Marium Navid, a UC Berkeley junior and ASUC senator who participated in the silent protest, said Maher’s discussion of liberalism was ironic, considering that he is “intolerant” of certain communities.

“(Free speech is) not the ability to stand on a pedestal and just say whatever you want,” Navid said.

Maher’s address follows previous commencement speeches from House of Representatives Minority Leader Nancy Pelosi, D-California, Apple Inc. co-founder Steve Wozniak and former U.S. secretary of state Madeleine Albright. Although the Californians — the organization responsible for selecting keynote speakers — voted to rescind his invitation in October after a petition to stop him from speaking received about 4,000 signatures, the campus administration chose to let the invitation stand.

Toward the end of his speech, Maher recounted a slogan made for his show, with a picture of his face and the phrase “He’s not in it for the likes.”

“It’s exactly what I wanted to grow up to be,” Maher said of the slogan. “Don’t be afraid to be a crazy person and understand that the truth is not always popular.”

News editor G. Haley Massara contributed to this report.

Melissa Wen is the executive news editor. Contact her at [email protected] and follow her on Twitter @melissalwen.