Look around you. Your shoes, that tree, the Starbucks cold brew you’re clutching—it’s all very much right here in the real world. But what if the “real world” we live and move around in is just a computer simulation? Neil deGrasse Tyson, everyone’s favorite astrophysicist, thinks there’s a very high chance that everything we know is just a hologram. He’s just one of a growing number of people who believe it.