Das war ein Vortrag beim Event *Logik zwischen den Fächern* im Hamburg. Man kann den Beamer hier finden.

# Talk: Indeterminateness and `The’ Universe of Sets

This will be a talk at the World Logic Day celebrations on 14th January 2021 at the Iranian Association of Logic. You can get the slides here.

# Talk/Slides: `Intensional Classes and Intuitionistic Topoi’ Barcelona Set Theory Seminar 9 December 2020

This will be a talk at the Barcelona Set Theory seminar on 9th December 2020. You can find the slides here.

Abstract: A popular view in the philosophy of set theory is that of **potentialism**: the position that the set theoretic universe unfolds as more sets come into existence. A difficult question for the potentialist is to explain how *classes* (understood as intensional entities) behave on this framework, and in particular what logic governs them. In this talk we’ll see how category-theoretic resources can be brought to bear on this issue. I’ll first give a brief introduction to topos theory, and then I’ll explain how (drawing on work of Lawvere) we can think of intensional classes for the potentialist as given by a functor category. I’ll suggest some tentative directions for research here, including the possibility that this representation indicates that the logic of intentional classes should be intuitionistic rather than classical, and that the strength of the intuitionistic logic is dependent upon the partial order on the worlds.

# Talk/Slides: Intensional Classes and Intuitionistic Topoi

This will be a talk at UNICAMP on 8th December. You can find the slides here.

Abstract: A popular view in the philosophy of set theory is that of **potentialism**: the position that the set theoretic universe unfolds as more sets come into existence. A difficult question for the potentialist is to explain how *classes* (understood as intensional entities) behave on this framework, and in particular what logic governs them. In this talk we’ll see how category-theoretic resources can be brought to bear on this issue. I’ll first give a brief introduction to topos theory, and then I’ll explain how (drawing on work of Lawvere) we can think of intensional classes for the potentialist as given by a functor category. I’ll suggest some tentative directions for research here, including the possibility that this representation indicates that the logic of intentional classes should be intuitionistic rather than classical, and that the strength of the intuitionistic logic is dependent upon the partial order on the worlds.

# Talk/Slides: `Algebraic Levels in Mathematical Structuralism’

This will be a talk at the Oxford Philosophy of Mathematics Seminar on 30. November 2020. You can look at the slides here.