Do the Gospels Contain Eyewitness Testimony?

What is the evidence for the eyewitness testimony of the Gospels? This clip comes from Dr. Mike Licona's debate with Dr. John Dominic Crossan on the Historical Jesus. This debate was held on October 24, 2018 at Kennesaw State University.

Correction: At 0:32, I should have said Papias says he received the information from a close associate of John the apostle, and did so while John was still preaching.