When Stephen Colbert returned his “Late Show” to the Ed Sullivan theater Monday night, his first guest was Jon Stewart. Normally, they make a pretty potent duo. But, for some reason, Stewart went off in a direction that surprised me.

He seems to have embraced the conspiracy theory that COVID-19 was created in a laboratory by scientists in Wuhan, China. Unfortunately, like everyone else who has made this claim — including Trump and his acolytes in right-wing media — there’s absolutely no evidence to back it up. The reason I was so disappointed to see Stewart so far down this path is that his rant is exactly the same sort of nonsense that he used to mercilessly mock Glenn Beck for on “The Daily Show.”

Stewart’s argument essentially came down to the fact that the virus came from a place called the Wuhan Novel Coronavirus Laboratory, and the name alone is proof. He joked that if there were a giant chocolate spill in Hershey, Pennsylvania, there wouldn’t be any doubt where it originated.

But Stewart’s logic is more akin to saying that the American Cancer Society is responsible for all the cancer in the world, or that the National Institute of Allergy and Infectious Diseases (the place Dr. Anthony Fauci runs) created hay fever and AIDS. In other words, the place’s name is confirmation of nothing more than an agency where scientists study some narrow field of research.

The truth is that, at this point, there is no tangible proof of where COVID-19 came from, and the reason you shouldn’t believe anyone’s proclamation otherwise is that they — Stewart, Trump, etc. — haven’t provided any evidence, peer-reviewed or otherwise. Being loud and mugging about it on television don’t qualify.