In this episode Joel acts really smart and Kurt listens. They talk about beauty as an objective truth and the reasons it's important to the church today. Joel basically steals his information from a bunch of sources but mainly from below:
Benjamin Zander The Transformative Power of Classical Music Video:
https://www.youtube.com/watch?v=r9LCwI5iErE&t=17s
http://www.cslewis.com/with-their-christianity-latent-c-s-lewis-on-the-arts/