The Download: Driverless cars' AI plan, and stretching cells with a robotic shoulder

Why you don't really know what you know October 2020 What does it really mean to know anything? How well can we understand the world when so much of our knowledge relies on evidence and argument provided by others? These questions matter not only to scientists. Many other fields are becoming more complex, and we have access to far more information and informed opinions than ever before. Yet at the same time, increasing political polarization and misinformation are making it hard to know whom or what to trust.