By Grabthar's Hammer, these two are insufferable. But I see from the comments that many find them adorable.
I'll concede the necessity of providing a general background, but it takes Ehrman far too long to get to the ostensible subject of the video, and then he sort of dances around it in a way that will probably just confuse most of his audience. If I were going to try to answer the question of whether Paul was an eyewitness to the resurrection of Jesus, I think I'd begin by explaining who Paul was, what he said about the resurrection, compare it to the accounts in Acts, and if there was time, maybe compare the gospels.
There is some useful information here, scattered among the giggling and smirking: the research on memory and eyewitnesses Ehrman refers to, especially, which he wrote about in Jesus Before the Gospels, one of his better books. I find it hard to believe he spent two years boning up on it, it sounds like a pastor's exaggeration to me, and he's so disorganized that I wonder how many viewers will be able to follow what he's talking about. (I encountered some of the literature on memory in the 1990s, in the wake of the Ritual Satanic Abuse scare, and much on the Jesus tradition before the gospels in the 1980s and afterward.)
One thing that has long bugged me is the inexactness of "the resurrection" in Christian discussion of the subject. It seems to me that it should refer specifically to the restoration of Jesus' body to life on the Sunday after his crucifixion, and by extension to his visits with his followers immediately afterward. In that sense there were no witnesses to the resurrection, at least according to the gospels. (Interestingly, the non-canonical Gospel of Peter depicts the disciple Simon Peter watching as Jesus or a symbolic avatar is carried out of the tomb. That gospel is not recognized by any church today, and the only existing copy dates from several centuries after Jesus' death. Some scholars speculate that it may draw on earlier traditions, but nobody knows.) But after awhile I realized that Christians, including scholars, used "resurrection" to refer to the cosmic fact of Jesus' victory over death, in which his raising is almost incidental. The empty tomb is equated with the resurrection, though it's not the same thing.
"Witness" has a similar vagueness. It refers not only to someone who saw the risen Jesus but to anyone at any time afterward who testified that the resurrection had happened. "Witness" and "testify" (not to mention the Greek martyr, which means "witness" and didn't originally denote someone who died for his or her beliefs) are basically synonyms. Someone who testifies that he believes that Christ was raised is also a witness to the resurrection, even centuries later.
"Eyewitness" at least seems more exact, though again, no one actually was an eyewitness to Jesus getting up from the slab, shedding his grave wrappings, and emerging (nekkid?) from the tomb. They were eyewitnesses to the appearances (another interestingly vague word) of the risen Lord. Although the gospels stress the fleshly, meaty substantiality of his risen body, the risen Jesus flits around the vicinity of Jerusalem, popping in and out of locked rooms, sometimes recognized by his followers and sometimes not. According to Paul in I Corinthians 15, however, the risen body was not and could not be of flesh, but of spirit.
So, what about Paul? One frustrating thing about him is that in his letters he's very coy about his witness to the resurrected Jesus. Maybe he said more when he was making converts and founding his churches. In I Corinthians 15 he says he's reminding them of what he preached to them:
3 For I delivered to you as of first importance what I also received: that Christ died for our sins in accordance with the Scriptures, 4 that he was buried, that he was raised on the third day in accordance with the Scriptures, 5 and that he appeared to Cephas, then to the twelve. 6 Then he appeared to more than five hundred brothers at one time, most of whom are still alive, though some have fallen asleep. 7 Then he appeared to James, then to all the apostles. 8 Last of all, as to one untimely born, he appeared also to me.
When I first sat down and compared Paul with the resurrection stories in the gospels, I was startled by the differences. He doesn't mention Mary Magdalene, and only Luke among the gospels mentions Jesus appearing to Peter ("Cephas" comes from the Aramaic for "rock," as "Peter" comes from the Greek, so most scholars believe that Paul is referring to Peter here). That's odd if Mark's gospel was written from Peter's preaching, as tradition claims; maybe Peter was just too modest ever to mention it?
The Twelve can probably be harmonized with appearances to the Eleven in the gospels, since Judas was no longer with them, but this too is a strange lapse. Didn't Paul know about Judas? Some scholars think that the betrayal of Jesus by Judas is a later legend, and I agree, but no one knows. The appearance to "more than five hundred brothers at one time" has been getting some attention lately from fundamentalist YouTubers, but it's more of an embarrassment: why do none of the gospels mention it? According to Acts, all of the brothers present after Jesus' ascension into Heaven numbered 120. What happened to the other 380?
"James" is generally thought to be the brother of Jesus. Again, this appearance isn't mentioned in any of the gospels or in Acts, though in Acts 15 this James is an authoritative figure in the Jerusalem church. "All the apostles" is confusing, aside from the fact that it doesn't appear elsewhere either. How many apostles were there?
And then, Paul says, Jesus appeared to him. As Ehrman asks rhetorically in the video, how did Paul know it was Jesus? He could have asked the same question about Ananias of Damascus, to whom Jesus appeared "in a vision" in Acts 9 after he appeared to Paul. (So Paul wasn't "last of all" after all.) Ehrman tosses out several possibilities, none of which seems plausible to me. In Acts Jesus tells Paul who he is, and would Jesus lie? (That sort of circularity is popular among apologists.) Maybe more to the point, does a vision count as "eyewitness"? Acts isn't a reliable source, but Paul is no help either.
Paul says he "received" the list of resurrection appearances. Where, from whom, did he receive it? Most scholars assume that he received it from Peter and James when he met them in Jerusalem. There are several reasons why this isn't a good answer, such as how Paul preached this stuff during the long period after his conversion but before he went to Jerusalem. Paul insists in Galatians that he received his gospel directly from Jesus, by revelation. Even fundamentalists are reluctant to take him at his word, for some reason. Don't they believe that the risen Lord could instruct Paul personally? I don't, but I'm an infidel.
Again, we'll never know. I've noticed before that Paul says he "received" his version of the Eucharist, the Christian communion meal, from "the Lord," and again I take him at his word, that this is what he believed even if I don't. Interestingly, though, his version agrees closely, almost word for word, with the versions in the synoptic gospels. (Mark, Luke, and Matthew.) Maybe Paul and the gospel writers drew on the same branch of tradition. If that's the case, then why are their accounts of the resurrection so wildly, impossibly different? I've been wondering lately if the gospels based their accounts of the Eucharist on Paul's, but if so, why did they ignore his list of resurrection appearances? I mean "ignore" deliberately: they knew it but didn't feel bound to follow it. Oral tradition varies a great deal in how well it preserves material. Sometimes a story will be passed along verbatim very accurately, while other stories are changed freely. That might have happened here.
I also wonder why Ehrman in his videos seems to be talking about his topics almost for the first time, as if these issues wouldn't have come up often in the courses he taught for decades. It seems to be his shtick, and I find it annoying. If I were new to biblical studies, I think I would find it confusing and unhelpful. Judging by the comments, I'm not sure that many of his fans really follow him. They're impressed by his credentials, which are certainly real enough, and by his opposition to fundamentalist Christianity, but they seem to miss a lot of what he says, and miss that his positions are as much at odds with their liberal, feel-good vision of Christianity as they are with conservative evangelicals'. Like C. S. Lewis's fans, they bask in the aura of his superior learning; it's not vital that they themselves learn.
