Bill Nye has a message for anti-abortion advocates. In a new video, he addresses the claim that abortion is murder, making it clear to these pro-lifers that, “You literally don’t know what you’re talking about.”

“Many, many more hundreds of eggs are fertilized than become humans,” he says, because not all of those eggs will attach to a woman’s uterine wall and result in pregnancy.

But if you’re going to hold that as a standard—that life begins at conception, and any egg that’s fertilized has the same rights as an individual—well, “Whom do you sue? Whom do you throw in jail?” he asks. “Every woman who has had a fertilized egg pass through her? Every guy whose sperm has fertilized an egg and then it didn’t become a human?”

Nye then goes straight after legislators, calling those who push anti-abortion laws “ignorant.” He explains, “It’s a reflection of a deep scientific lack of understanding,” adding, “You literally don’t know what you’re talking about.”

Nye is joining the millions of progressives who are speaking out against recent attempts by pro-life conservatives to defund Planned Parenthood and Republican presidential candidates who continue to equate abortion with murder to gain voter approval from their scientifically-ignorant voter base.