[ The Types Forum (announcements only),
http://lists.seas.upenn.edu/mailman/listinfo/types-announce ]
Dear all,
The next Proof Society Seminar will take place on Monday 17 November 2025 at
14:00 CET. Our speaker will be Juliette
Kennedy<https://urldefense.com/v3/__https://www.mv.helsinki.fi/home/jkennedy/__;!!IBzWLUs!SayVtV3brBLgqWkmgHaDynS1GMgWMTFqowXMRwfqcdWqOwrOX2NNEuEhODGoLhOREQmZwBABKWwU1mc-S6jkcKaNQCf8bCA$
>, from the University of Helsinki. Details can be found below.
The Proof Society
Seminar<https://urldefense.com/v3/__https://www.proofsociety.org/proof-society-seminar/__;!!IBzWLUs!SayVtV3brBLgqWkmgHaDynS1GMgWMTFqowXMRwfqcdWqOwrOX2NNEuEhODGoLhOREQmZwBABKWwU1mc-S6jkcKaN1HmoJQo$
> is the official seminar of the Proof
Society<https://urldefense.com/v3/__https://www.proofsociety.org/__;!!IBzWLUs!SayVtV3brBLgqWkmgHaDynS1GMgWMTFqowXMRwfqcdWqOwrOX2NNEuEhODGoLhOREQmZwBABKWwU1mc-S6jkcKaNtbyTFns$
>, and it presents talks by leading researchers from all areas of proof
theory. Everyone who is interested in the subject is warmly invited to attend!
The talks take place online via Zoom, usually on Mondays, approximately once
per month. They start at 13:00 UTC and may last up to 75 minutes plus questions.
Kind regards,
Lev Beklemishev
Anupam Das
Marianna Girlando
---- Proof Society Seminar, Monday 17.11.2025, 14:00 CET ---
How first order is first order logic?
Juliette Kennedy, University of Helsinki
Fundamental to the practice of logic is the dogma regarding the first
order/second order logic distinction, namely that it is ironclad. Was it always
so? The emergence of the set theoretic paradigm is an interesting test case.
Early workers in foundations generally used higher order systems in the form of
type theory; but then higher order systems were gradually abandoned in favour
of first order set theory—a transition that was completed, more or less, by the
1930s.
In this talk I will look at first order logic from various points of view,
arguing that the distinction between first order and higher order logics, such
as second order logic, is somewhat context dependent. From the philosophical or
foundational point of view this complicates the picture of first order logic as
a canonical logic.
The seminar takes place via Zoom:
https://bham-ac-uk.zoom.us/j/84261727269
Meeting ID: 842 6172 7269
