We're taking this week off from publishing new episodes, so today we're bringing you an episode from "The Argument" about one of my favorite topics: aliens. We'll be back with new episodes of "The Ezra Klein Show" on Tuesday.With the U.S. government puzzling over U.F.O.s, and potentially habitable exoplanets in our telescopes, earthlings are closer than ever to finding other intelligent life in the universe. So the existential question is: Should we try to communicate with whatever we think might be out there?That’s the argument this week between Douglas Vakoch and Michio Kaku. Vakoch, the president of the research and educational nonprofit METI (Messaging Extraterrestrial Intelligence) International, has dedicated his life’s work to intentionally broadcasting messages beyond our solar system.Kaku, a professor of theoretical physics at the City College of New York and a co-founder of string field theory, thinks reaching out to unknown aliens is a catastrophically bad idea and “would be the biggest mistake in human history.”Together, they join Jane  to debate the question of making first contact and our place in the cosmos.Mentioned in this episode:Adam Mann, The New Yorker: “Intelligent Ways to Search for Extraterrestrials”Gideon Lewis-Kraus, The New Yorker: “How the Pentagon Started Taking U.F.O.s Seriously”Arik Kershenbaum, The Wall Street Journal, “Alien Languages May Not Be Entirely Alien to Us”“Star Trek: The Next Generation,” Season 4, Episode 15: “First Contact” (Netflix)The Ezra Klein Show: “Obama Explains How America Went From ‘Yes We Can’ to ‘MAGA’”You can find more episodes of "The Ezra Klein Show" at nytimes.com/ezra-klein-podcast, and you can find Ezra on Twitter @ezraklein.Thoughts? Guest suggestions? Email us at ezrakleinshow@nytimes.com.“The Ezra Klein Show” is produced by Annie Galvin, Jeff Geld and Rogé Karma; fact-checking by Michelle Harris; original music by Isaac Jones; mixing by Jeff Geld, audience strategy by Shannon Busta. Special thanks to Kristin Lin.