[HN Gopher] Transcendental Syntax
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       Transcendental Syntax
        
       Author : 4ad
       Score  : 51 points
       Date   : 2025-01-03 21:24 UTC (1 days ago)
        
 (HTM) web link (github.com)
 (TXT) w3m dump (github.com)
        
       | 4ad wrote:
       | Guide (in French): https://tsguide.refl.fr/ts.html
       | 
       | Theory: https://ncatlab.org/nlab/show/transcendental+syntax
       | 
       | More Theory:
       | https://ncatlab.org/nlab/show/Geometry+of+Interaction
       | 
       | Some sort of explanation:
       | https://x.com/noncanonicAleae/status/1874893997791170719
        
       | idlewords wrote:
       | This is so French that a baguette appeared in my hand after I
       | clicked the theory link. Probably a cognitive hazard to anyone
       | who is really into generics.
        
       | illogicalconc wrote:
       | I haven't been keeping up with Girard as much as I would like,
       | but am I correct in intuiting that this is the next step past
       | Ludics?
       | 
       | Update: I don't see a citation, so I guess this is an exploration
       | in a different direction.
        
         | Twey wrote:
         | This is a further step in the same programme. The programme
         | itself is somewhat agnostic as to the underlying dynamics; the
         | 'stellar resolution' mechanism (Eng's terminology, not
         | Girard's, who AFAIR doesn't name the system) is a better-
         | behaved replacement for the 'designs' of _Locus Solum_, which
         | IMO remains the best introduction for the bigger ideas of the
         | programme.
        
       | dboreham wrote:
       | I've not been following since around 1985 when I realized there's
       | no such thing as semantics. Is this mainstream now?
        
         | saithound wrote:
         | Of course. Pretty hard to deny it when transformers learmed to
         | produce useful human language not by figuring out how it
         | relates to some Tarskian "true reality" but by looking at a lot
         | of text and figuring out its internal use, exactly as Girard
         | (and implicitly Kant) predicted it would happen.
         | 
         | Girard even noted that we'd know progress was happening as soon
         | as early models started making certain specific kinds of
         | mistakes children also tend to make, such as the answer to
         | "which is heavier, 5kg of bricks or 5kg of feathers".
         | 
         | So yes, Kant, Girard and you got this right early on, but the
         | mainstream has caught up since then.
         | 
         | Of course, semantics still works well as a technical tool in
         | formal logic, though it has no link to its philosophical
         | counterpart (not that this prevents B-grade philosophers from
         | abusing the unfortunately chosen terminology to equivocate
         | them).
        
           | dboreham wrote:
           | Good to hear. I need to look up my Philosophy major friend
           | who disagreed with me in 1985 and issue a formal "I told you
           | so" notice ;)
        
       | qazxcvbnm wrote:
       | On the topic of Girard, I've been very attracted to his ideas
       | about the "dynamics" of logic and "communication without
       | understanding". It always appears to me that such ideas and
       | things like the "execution formula" should have profound
       | implications on static analysis of algorithms and things like
       | abstract interpretation and collapsing stacks of interpreters.
       | 
       | Has there been any literature on concrete steps in this
       | direction, or is there anything holding back Girard's theories
       | from practical application (I know that Girard's Geometry of
       | Interaction was supposed to have problems with additives, of
       | which exact implications I do not quite comprehend, which may or
       | may not be relevant)?
        
       | woolion wrote:
       | This is an implementation of Girard's "transcendental syntax"
       | program which aims to give foundations to logic that do not rely
       | on axiomatics and a form of tarskian semantics (tarskian
       | semantics is the idea that "A & B" is true means that "A" and "B"
       | is true; you've simply changed the and to a "meta" one rather
       | than the logical one). This program is more than 10 years old,
       | with first written versions appearing around 2016, and the ideas
       | appearing in his talks before that.
       | 
       | Girard has been a vocal critic of foundational problems, labeling
       | them as "hell levels", with the typical approach of set theory
       | and tarskian semantics as the lowest one and category theory as a
       | "less worse" one (at least one level above). One issue with his
       | program is that he mixes abstract, philosophical ideas with
       | technical ones. So even if some things have interesting technical
       | applications, they may be different when seen from a more
       | philosophical point of view. For instance, set theory as the
       | foundations of mathematics is a pretty solid model but it is seen
       | as fundamentally unsatisfying for many reasons -- most famously
       | the continuous hypothesis. Godel and other very high-profile
       | mathematicians thought it was a very unsatisfying issue even
       | though from a mathematical model theory point of view, it's not
       | even a paradox. So the new foundational approaches tend to have
       | maybe deeper philosophical problems about them; for example see
       | Jacob Lurie's critic of the Univalent foundations program (after
       | the "No comment" meme he expressed a long list of issues with
       | it).
       | 
       | The other issue with this particular work is that it uses new
       | vocabulary for everything to avoid the bagage of usual
       | mathematical logic, but it kind of give a weird vibe to the work
       | and make it hard to get into without dedicating much work.
       | 
       | The result is therefore something that is supposed to solve many
       | longstanding problems in philosophical and technical approaches
       | to the foundations of mathematics but has not had a big impact on
       | the community. This is not too surprising either because the
       | lambda calculus or other logical works were seen as trivial
       | mathematical games. We'll see if it's a case of it being too
       | novel to be appreciated fully, and this work seems to try to
       | explore it in a technical way to answer this question.
       | 
       | https://girard.perso.math.cnrs.fr/Logique.html (in French, it
       | gives an overview of the program)
       | 
       | https://girard.perso.math.cnrs.fr/Archives.html (transcendental
       | syntax papers are there in English)
        
       | LudwigNagasena wrote:
       | I'm sympathetic towards Girard's dissatisfaction with the current
       | state of model theory, but I don't see how his project may in any
       | practical sense fix it.
        
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