Videos:
I’ve been invited to the podcast aboutlogic, hosted by D. Sarikaya and T. Altenkirch:
(German) I briefly explain the concept of mathematical axioms:
Texts and books:
(German) An introduction into forcing and set-theoretic independence:

Visser: Do you believe that the empty set exists?
Me: I don’t have any beliefs on the existence of sets.
Visser: But then the set of your beliefs on the existence of sets is the empty set.
Hamkins: It’s one of them.
(at Ouroboros, Bonn 02/18)