How do doctors actually think? And if we can answer that, can we train a computer to do a better job? In the post-WW2 period, a group of iconoclastic physicians set about to redefine the nature and structure of clinical reasoning and tried to build a diagnostic machine. Though they would ultimately fail, their failure set the stage for the birth of the electronic health records, formalized the review of systems, and set up a metacognitive conflict that remains unresolved to this day. This episode, entitled "The Database," is the second part of this on the history of diagnosis with Gurpreet Dhaliwal.