Joost Johannes Joosten Title: Interpretability principles and logics for weak arithmetic theories Abstract: In this talk we will speak on various aspects of interpretability logics which are extensions of Gödel-Löb’s provability logic GL using a new binary modality to model formalised interpretability. We will consider the basic interpretability logic IL and various extensions where we shall be interested both in modal as in arithmetical semantics. We will discuss some history, some recent developments and some open questions. In particular, we shall address the question on how to describe a collection of modal interpretability principles that can be proven sound in any theory that interprets Kalmar Elementary Arithmetic.