Textbook Group meeting for Parr, Pezzulo, Friston 2022 .

all right welcome cohort 5 it's March 11th and Andrew thanks for taking us on to chapter eight part two so go for it all right okay it's our second week on chapter eight um and just a brief refresher that this chapter is in the second part of the text book and so we're now focusing more upon building our own models and getting a sense of how to draw relationships between phenomena of interest and how to actually map them to variables in active inference models chapter 7even we saw um discrete State space models and so we were looking at pdps and now chapter 8 now transitions to continuous State space models which is sort of the the found ation uh the starting point for uh historically for developing active inference models a lot of the earlier work of uh frisen par and others was on continuous models first um so here we're looking at continuous State space models which are well suited for modeling let's say physical fluctuations uh impinging on sensory receptors and for the continuous motion of the ectors or muscles we use to change the world around us is a quote from the chapter um here we have model examples for dynamical systems involved in motor control as well as the concept of generalized synchrony with the bird song example and finally constructing Hybrid models uh near the end which would actually combine discrete and continuous variables um so it kind of almost add mixture of what we confronted in chapter 7 now with continuous variables being situated as well for example at a lower level of the model um since it's our second week uh from there I think we could just jump in does anyone have any thoughts uh on this chapter any questions anything they're they're still kind of uh crunching through uh in their mind about about how a lot of this works [Music] all I'll at one point thank you Andrew for the quick opening I think it's an interesting point that like you said it was initially uh with the earlier FR and Par models in continuous time and now the continuous time is being Revisited in the basy mechanic setting so it's kind of like a purely dynamical systems justification which is very similar to the SPM textbook so kind of classical equations of motion which kind of turns out to be like the um classical Newtonian basian mechanic so the kind of pre uh continuous time which is where most of the this chapter's Focus um like including just the differential equations including the chaotic deterministic systems that's just the kind of pure dynamical systems approach again very similar to SPM and then this textbook doesn't really go into basing mechanics because this textbook was published March 2022 so probably was written um between First's 2019 free energy principle for a particular physics and then obviously the book being published in so it's mentioned but many of the works that that made it clearer are only after the book just to kind of give a little more context on the continuous time yeah so we start with continuous we move to discreet and now we're back to continuous but it's kind of using what's been developed since then and also being able to yeah combine the two um as well yeah in the the nested hybrid model at the end of chapter 8 is basically like picked up on by this paper which we discussed in live stream 46 and they basically pick up on that exact hybrid model I don't know if they use a figure let's see the hybrid 86 on page 166 oh sorry sorry yeah yeah you're looking at the paper yeah just that but I don't know they didn't include it there but uh here yeah figure 8.6 so here continuous time on the bottom because of the D derivatives and then discrete time on the top because of the transition Matrix and the explicit time and then in this paper they say okay with a belief desire intention like BDI model including discussion of like whether that is f psychology etc etc but within that commonly used like can you talk about beliefs desires and intentions and all these things they it it's not that it does…