Republican presidential candidate Sen. Rand Paul (R-KY) said during a Thursday interview on Fox News that colleges have become so overly sensitive that “it’s almost like they’ll put you in prison” for rejecting mainstream climate science.

“Only certain opinions are acceptable on college campus,” Paul told Fox’s Gretchen Carlson. “It’s almost like they’ll put you in prison for challenging the religious dogma on climate change.”

Paul and Carlson were discussing free speech on college campuses, a conversation that has been reignited by a recent spate of incidents at the University of Missouri, Yale University, and Ithaca College.

The libertarian-leaning Republican argued that college students today have “become intolerant and they really have no sense of humor.”

“We’ve become overly sensitive,” Paul said in the interview. “People can’t tell a joke, people can’t have an opinion… I think we need more robust debate.”

Paul himself took issue with climate science during Tuesday’s GOP presidential debate on Fox Business.

“The planet’s 4.5 billion years old,” he said. “We’ve been through geologic age after geologic age. We’ve had times when the temperature’s been warmer, we’ve had times when the temperature’s been colder. We’ve had times when the carbon in the atmosphere’s been higher.”

Watch part of Paul’s Fox interview below.