In the 1920s, the scientist Werner Heisenberg came up with a wild idea that broke reality as Western science knew it. And it's still unsettling to think about. Benjamin Labatut's recent book, When We Cease to Understand the World, makes readers feel the aftershocks of the revelation, asking, "What's real?" For more, go to http://vox.com/unexplainable It’s a great place to view show transcripts and read more about the topics on our show. Also, email us! unexplainable@vox.com We read every email. Support Unexplainable by making a financial contribution to Vox! bit.ly/givepodcasts Learn more about your ad choices. Visit podcastchoices.com/adchoices