Thank you, Eetu. This framing of the relationship seems right, as far as it goes.
I’ll paste here an excellent post by Martin to ECACSnet, and your ensuing exchange with him, Warren, which I’m sure you remember. I think this is important to have in the Discourse record.
[Martin Taylor 21.04.27.10.49]
Warren, I don’t know what Friston or his followers think. Sometimes I don’t even know what I think, but PCT explains this last, since perceptions in the fully reorganized hierarchy are controlled non-consciously. We don’t consciously think about what we do to bring those perceptions nearer their reference values. But we often encounter situations that we perceive consciously and we perceive that they are not the way we want them to be. And that’s where mutual entropy comes in.
To answer to your last question: "Where is their architecture they can be lit into this mode that PCT so clearly describes? " is Seth A. K., & Friston K. J. (2016), Active interoceptive inference and the emotional brain. Phil. Trans. R. Soc. B 371: 20160007. http://dx.doi.org/10.1098/rstb.2016.0007. That’s the architecture I pointed out in CSGnet and in PPC Section 7.3 as functionally equivalent to the Powers architecture, while being possibly more powerful in explaining phenomena.
Now to the meat of you message. Ignore the maths, which are the heart of Friston’s publications — at least those I have seen. “Entropy” is really quite simple in principle. You have a measure of uncertainty (a.k.a. entropy) for any variable. It’s the same kind of measure as variance, just a way of describing how a set of values vary among themselves. Often those values are of the same variable at different times, but also often they are different values the variable might have at a given moment such as “now”. So if you have two variables, you have two uncertainties. Let’s say that one variable is in the environment, a complicated function of variables that are controllable in the reorganized hierarchy, but not a function that you know. The variable in the environment has some uncertainty both over time and possibly over variation in this novel function. There is also a variable that is the environmental correlate of the current reference value, so it, too has some uncertainty.
Then between two variables there is mutual uncertainty (a.k.a. mutual entropy), which is actually another variable, the uncertainty about one variable that is left when you know the value of the other. Uncertainty has a flip side, a complementary variable we call “information”. Information is always a reduction in uncertainty as a consequence of something such as an event or an observation. In control, you are acting to minimize the uncertainty of the perception (or of the Corresponding Environmental Variable) given the value of the reference variable. In terms of information, you are trying to maximize the mutual information between reference and perception (or the CEV).
Where does “free energy” come into this? That again is easy in principle, though perhaps not in detail. It takes energy to reduce entropy (uncertainty) or to maintain a reduced entropy of a variable. Perceptual control minimizes the mutual uncertainty between reference and CEV. It does this by using an energy flow from a source to a sink into which the control system dumps the entropy it removes from the CEV. The disturbance would supply energy to the CEV, but by using this through energy flow, the output extracts this energy by opposing it, dumping the disturbance’s energy (and the entropy it would have added to the CEV) into the waste flow out to the environment. IN all this, PCT and FEP are in complete agreement. Indeed, in a CSGnet message some years ago, and repeated in PPC Fig 7.2, I used a hierarchical connection taken from a paper by Seth and Friston as a possible mathematically equivalent alternative to the Powers hierarchical connection.
The equivalence between the Free Energy Principle and PCT breaks down in two places: (1) In the PCT non-conscious reorganized hierarchy the action output at every level has already been pre-wired. You don’t have to think, you just do. Later, you may think about what you did, but it has already been done. The Friston approach doesn’t allow for that AFAIK. You think about how to act in order to achieve minimal mutual uncertainty (entropy) between prediction (a.k.a. reference) and observation post-action; (2) PCT (and Powers in informal communications) has no position on the function of conscious thought, other than Powers’s assertion that every conscious perception is constructed in the reorganized hierarchy, but Friston, not having a reorganized hierarchy, makes no distinction among levels.
Putting these two differences together, we have that the FEP hierarchical architecture is equivalent to the Powers hierarchical architecture, at least on the perceptual side of the hierarchy, and can apply to conscious thought, which is not incorporated in the Powers architecture other than through the within-level imagination loop inside the reorganized perceptual control hierarchy.
Where FEP and PCT disagree most strongly is in that FEP requires analysis of the probable effects of different actions on the predicted value of the (in PCT) controlled perception, and a choice as to which actions, given the current observed state of the world, will most closely bring the observation to match the prediction. I earlier equated the predicted value with the reference value, but I don’t remember reading an FEP paper that talks about desired values. I imagine that Eva or someone could fill that hole in the argument (Eva because I seem to remember that she came to PCT from FEP).
When the perception that you consciously want to change is not of a situation you have encountered, you probably don’t have the actions to bring it to a reference value already reorganized into the hierarchy. Think of encountering chess for the first time. Every layout of the 32 pieces on the board makes as much sense as any other, except that the starting position looks a lot more regular than any other. To learn to play chess well, you have to learn to see some other layouts of the pieces as being significant — as being perceptions with values that need (or do not need) to be changed if you want to win the game. Initially, you have to work out “If I do this, then the resulting layout will be like that. Have I ever seen the result of that move? Is the resulting layout one I have seen to be promising or dangerous ?” and so forth for doing “this” and for doing “that”.
The more perceptions of layouts you have seen, the less you have to think whether the possible move brings the reference value “I win” nearer to the perceptual value of the whole complex board layout. More and more small patterns become perceptions reorganized into the non-conscious hierarchy, and the more of those small patterns become parts of larger patterns involving more pieces. But even Grand Masters have to think when opposing equally skilled opponents (though possibly not when playing 32 amateurs while blindfolded).
In all this, chess is a world, a Universe of possibility in which the Free Energy Principle of considering the effects of actions in the current world situation is needed only in more and more complex “layouts” that one has not yet learned the actions that would alter the controlled variable toward its reference value (winning in chess, becoming and remaining happy and healthy, perhaps, in life). As one learns more, more and more complex perceptions become included in the reorganized hierarchy, where one does not need to think about what to do.
This is very long, I know. But does it make sense to you? Does it answer your questions? Does it explain why I think FEP applies to conscious control, and is mathematically compatible with PCT in the reorganized hierarchy, though thinking about what to do under “these” circumstances is not compatible with the non-conscious reorganized hierarchy?
[Martin Taylor 21.04.30.10.46]
On 2021/04/30 9:35 AM, Warren Mansell wrote:
I found this really helpful:
And it led me to this:
"So control information is information that which can be reliably re-experienced and identified by the perceiver regardless of disturbances. To do so requires an input function that identifies this source of information, and a means to act against disturbances (e.g. movements, distortions, loss of data) that might render it unidentified. Otherwise the purpose or function of the information to the perceiver is redundant – it is just a meaningless pattern impinging on the senses.
“So control information is information that which can be reliably re-experienced and identified by the perceiver regardless of disturbances.”
So far so good. PCT would agree. But …
"To do so requires an input function that identifies this source of information, and a means to act against disturbances (e.g. movements, distortions, loss of data) that might render it unidentified. Otherwise the purpose or function of the information to the perceiver is redundant – it is just a meaningless pattern impinging on the senses. "
PCT would strongly disagree, for those perceptions whose control is in the hierarchy. All that is required is that some action pattern has been constructed that will move the perception in a consistent direction. The last sentence is unintelligible. What has the source to do with the ability to control a perception? What could the information available from a perception be redundant with?
The writer seems to believe that meaning to a perceiver is imposed from outside. PCT says that meaning depends on what one wants the world to be like a compared with how it is perceived to be. It is inside the observer/actor. Shannon pointed this out in his seminal Mathematical Theory of Communication, without involving what the receiver wants. What Shannon said (and this is true of Kolmogorov uncertainty as well) is that the information gained by a receiver from a message (observation) depends on what the receiver knows already that is augmented or changed by reception of the message (observation). It has nothing to do with the sender of the message, or the state of the world that is observed. What the observer/receiver gets out of the message (observation) depends on the fit between the decoding apparatus (perceptual functions) and the coding done by the sender (the actual construction of Real Reality, of which Perceptual Reality is a decoded version).
Anyway, I would say that abstracted paragraph has a valid message hidden in a mass of gobbledygook. The last sentence makes nonsense of what precedes it.
Warren Apr 30, 2021, 11:22 AM:
Hi Martin, you said “PCT would strongly disagree, for those perceptions whose control is in the hierarchy”
Sorry, I should explain, my point is about new variables for which there is not yet a learned input function… So my point is that to use reorganisation to develop a reliable, accurate input function to identify a variable, the system needs to be acting against disturbances so that a new trial-and-error candidate for the input function settles through reduction in error…
Martin Taylor 21.04.30.11.33]
OK. That makes a bit more sense. That is where I suggested that the Free Energy Principle approach comes into play. Consciously a bunch of different perceptions are, for some reason taken together as meaning something with respect to what you already know or want. Together, those perceptions are of some function in Real Reality, which could be but is not yet joined to become a function in a White Box (perceived Object). At this point, the consciously perceived value of this concatenation of perceptual values differs from what you want it to be.
By manipulating one or more of the perceptions already controllable in the hierarchy, just as one would if the new function were already reorganized into the hierarchy, the result might be closer to what you want. If you can perceive states in the outer world, you could manipulate their avatars in imagination — Plan a course of action, and if that seems as though it wouldn’t work, check out Plan B, Plan C, etc. non-destructively in imagination, using control of perceptions you already can control, or imagining simpler structures that might be part of the one you started with. “Peace in the World” might be an desired state too difficult to achieve with an imaginable plan that involves only perceptions you already can control.
The imagined Plan A, Plan B, … are predictions in the sense of FEP. If the perceptions to be controlled according to a plan do correspond to “the way the world is” (including your ability to control perceptions that the plan requires you to control), then if the plan produces the desired result in imagination, it may well do so when put into practise by controlling those controllable perceptions that form part of the as yet uncontrollable perceptual complex. That’s FEP “prediction”. If it doesn’t work in Real Reality, the reason might be perceptible. At least, something might have changed, including the uncertainty about the state of the world (CEV) that you are trying to control, given the state you want it to take on.
Though you don’t mention imagination, this may be what you are thinking of in your clarification when you say “my point is that to use reorganisation to develop a reliable, accurate input function to identify a variable, the system needs to be acting against disturbances so that a new trial-and-error candidate for the input function settles through reduction in error.”.