Lecturer I believe. As I understand it, and I'll fully admit my understanding is quite poor, you need to have a Master's Degree to teach at a university and a doctorate to actually be a professor.

In his partial defense, I don't think he's that bad of an interviewer, and his guests are quite varied - Joe Rogan said that he would NOT invite Trump. I chuckle when I hear people describe him as smart, but that may just be because he's so uncharismatic and because he doesn't speak well - I doubt I could earn a a technical MSc at any university, let alone MIT.