1. Introduction

    1. The laws of physics as analogs for the axioms of a formal system

    2. How space-time surfaces could act on space-time surfaces as morphisms

    3. How zero energy states identified as selves could act on each other as morphisms?

  2. G\"odel and Lawvere

    1. G\"odel's incompleteness theorems

    2. The fixed point theorem of Lawvere

  3. TGD perspective

    1. How quantum TGD could define a physical analog of a formal system?

    2. Self reference: could space-time surfaces represent statements about space-time surfaces as analogs of sentences?

    3. Comments inspired by the article Jenny Nielsen and Lucis Semita about provability of Riemann Hypothesis

  4. TGD does not lead to the paradox with the notion of self