Yale President Peter Salovey spoke on free expression on campuses, reflecting on a recent incident at the University of California, Berkeley, where students protested comedian Bill Maher’s appearance at a graduation ceremony because of controversial comments he made about Muslims.

“It’s very difficult. You see this controversy playing out on many different campuses over the last couple of years,” Salovey said.

Salovey said he thinks people want to live in an environment where others are respectful and civil, but being offended can be a learning experience.

“It’s fine to protest, it’s fine to raise one’s own voice,” Salovey said. “The most effective way to combat speech you don’t like is with speech.”

Below, live updates from the 2015 Davos Annual Meeting: