# Fundamentals **URL:** http://discourse.iapct.org/c/research/6.md [Latest](http://discourse.iapct.org/latest.md) · [Categories](http://discourse.iapct.org/categories.md) · [Tags](http://discourse.iapct.org/tags.md) --- ## [About the Fundamentals category](http://discourse.iapct.org/t/about-the-fundamentals-category/14)
**Author:** [@forumControlSystem](http://discourse.iapct.org/u/forumControlSystem)\ **Replies:** 0\ **Last updated:** [September 8, 2019, 2:06pm UTC](http://discourse.iapct.org/t/about-the-fundamentals-category/14 "2019-09-08T14:06:33Z")
This category is for discussions of PCT fundamentals. --- ## [How is control prioritised across the whole system?](http://discourse.iapct.org/t/how-is-control-prioritised-across-the-whole-system/16269)
**Author:** [@Kuba](http://discourse.iapct.org/u/Kuba)\ **Replies:** 2\ **Last updated:** [October 1, 2026, 11:05pm UTC](http://discourse.iapct.org/t/how-is-control-prioritised-across-the-whole-system/16269 "2026-10-01T23:05:37Z")
Control loops operate simultaneously. Higher-level systems set goals for lower-level systems. Ongoing corrections happen at different levels without conscious supervision. What determines which control processes are mai… --- ## [Sending the Free Energy Principle to the Dark Room](http://discourse.iapct.org/t/sending-the-free-energy-principle-to-the-dark-room/16252)
**Author:** [@Lukasz20](http://discourse.iapct.org/u/Lukasz20)\ **Replies:** 15\ **Last updated:** [August 3, 2026, 7:37pm UTC](http://discourse.iapct.org/t/sending-the-free-energy-principle-to-the-dark-room/16252 "2026-08-03T19:37:37Z")
Fellow control theorists, For years we have watched the Free Energy Principle absorb every objection thrown at it, the way a good attractor absorbs a disturbance. Say it predicts the wrong thing and you are told it is o… --- ## [Is Psychology Going to Cincinnati? (Adam Mastroianni @ SFI)](http://discourse.iapct.org/t/is-psychology-going-to-cincinnati-adam-mastroianni-sfi/16147)
**Author:** [@hugocristo](http://discourse.iapct.org/u/hugocristo)\ **Replies:** 11\ **Last updated:** [May 19, 2026, 1:07pm UTC](http://discourse.iapct.org/t/is-psychology-going-to-cincinnati-adam-mastroianni-sfi/16147 "2026-05-19T13:07:52Z")
Hello everybody, Adam Mastroianni runs a very interesting Substack blog called Experimental History. I highly recommend his recent lecture at the Santa Fe Institute: He discusses many (controversial) topi… --- ## [PCT vs Free Energy (Specification versus Prediction)](http://discourse.iapct.org/t/pct-vs-free-energy-specification-versus-prediction/16088)
**Author:** [@rsmarken](http://discourse.iapct.org/u/rsmarken)\ **Replies:** 65\ **Last updated:** [January 6, 2026, 10:42pm UTC](http://discourse.iapct.org/t/pct-vs-free-energy-specification-versus-prediction/16088 "2026-01-06T22:42:17Z")
I’ve been trying to find some clear description of the relationship between PCT and Friston’s “Free Energy” (FE) model of behavior. Apparently there was some discussion about it on CSGNet back in early 2019 but it never … --- ## [Neurophysiology of Behavior](http://discourse.iapct.org/t/neurophysiology-of-behavior/16163)
**Author:** [@rsmarken](http://discourse.iapct.org/u/rsmarken)\ **Replies:** 0\ **Last updated:** [March 19, 2025, 8:53pm UTC](http://discourse.iapct.org/t/neurophysiology-of-behavior/16163 "2025-03-19T20:53:28Z")
Here is a wonderful paper by Henry Yin that explains very clearly why much (most?) of current neurophysiological research tells us little about the neurophysiological basis of behavior. Spoiler alert: It’s becuase it is … --- ## [Phenomena Phirst Redux](http://discourse.iapct.org/t/phenomena-phirst-redux/16145)
**Author:** [@rsmarken](http://discourse.iapct.org/u/rsmarken)\ **Replies:** 6\ **Last updated:** [December 11, 2024, 8:45pm UTC](http://discourse.iapct.org/t/phenomena-phirst-redux/16145 "2024-12-11T20:45:57Z")
Warren Mansell suggested that I post this offline Q & A between Bruce Nevin and myself so here it is. Warren suggested the topic title since that seems to be the main theme of our interaction. This topic of Phenomena Phi… --- ## [Reorganization of Input (perceptual) Functions](http://discourse.iapct.org/t/reorganization-of-input-perceptual-functions/16098)
**Author:** [@rsmarken](http://discourse.iapct.org/u/rsmarken)\ **Replies:** 8\ **Last updated:** [November 17, 2024, 2:24am UTC](http://discourse.iapct.org/t/reorganization-of-input-perceptual-functions/16098 "2024-11-17T02:24:59Z")
Continuing the discussion from PCT vs Free Energy (Specification versus Prediction): I think the term that best describes input functions is “perceptual functions”. The perceptual functions in PCT are assumed to be neu… --- ## [The story of E. coli chemotaxis](http://discourse.iapct.org/t/the-story-of-e-coli-chemotaxis/16109)
**Author:** [@smithmarkl](http://discourse.iapct.org/u/smithmarkl)\ **Replies:** 4\ **Last updated:** [November 13, 2024, 12:38am UTC](http://discourse.iapct.org/t/the-story-of-e-coli-chemotaxis/16109 "2024-11-13T00:38:14Z")
This page has been doing the rounds on some of the computer tech blogs and social media and I wanted to share it here. It’s a pretty deep technical dive into how E. coli chemotaxis works. The Baffling Intelligence of a… --- ## [Goal: minimize alienation](http://discourse.iapct.org/t/goal-minimize-alienation/16134)
**Author:** [@bnhpct](http://discourse.iapct.org/u/bnhpct)\ **Replies:** 2\ **Last updated:** [October 31, 2024, 8:10pm UTC](http://discourse.iapct.org/t/goal-minimize-alienation/16134 "2024-10-31T20:10:00Z")
An important goal for PCT is understanding (and fostering) social arrangements in which the people enacting them are better able to identify and control their own CVs. Informally, such arrangements are more ‘fulfilling’… --- ## [First self-replicating RNA molecule](http://discourse.iapct.org/t/first-self-replicating-rna-molecule/16105)
**Author:** [@bnhpct](http://discourse.iapct.org/u/bnhpct)\ **Replies:** 19\ **Last updated:** [April 26, 2024, 6:39pm UTC](http://discourse.iapct.org/t/first-self-replicating-rna-molecule/16105 "2024-04-26T18:39:03Z")
Bill postulated the first emergence of life in the form of self-replicating molecules that were capable of self-repair, a fundamental form of resistance to environmental disturbances. evolution\_purpose1995.pdf (179.7 KB… --- ## [Reorganisation at every level of the perceptual hierarchy](http://discourse.iapct.org/t/reorganisation-at-every-level-of-the-perceptual-hierarchy/16084)
**Author:** [@Evadeh](http://discourse.iapct.org/u/Evadeh)\ **Replies:** 1\ **Last updated:** [October 29, 2023, 12:33pm UTC](http://discourse.iapct.org/t/reorganisation-at-every-level-of-the-perceptual-hierarchy/16084 "2023-10-29T12:33:54Z")
Dear all, At the 2023 IAPCT conference, I presented my ideas on how reorganisation has a different character at every level of the perceptual hierarchy. I would love to hear your ideas and suggestions in this topic. Do … --- ## [Modeling hierarchical control](http://discourse.iapct.org/t/modeling-hierarchical-control/16069)
**Author:** [@Evadeh](http://discourse.iapct.org/u/Evadeh)\ **Replies:** 33\ **Last updated:** [October 4, 2023, 4:01pm UTC](http://discourse.iapct.org/t/modeling-hierarchical-control/16069 "2023-10-04T16:01:26Z")
hi all, Together with Ton van Amelsfort, a science teacher at Technical University Eindhoven, I’m working on trying to model hierarchical control in Vensim software. This exercise teaches us many things about PCT, espec… --- ## [Bidirectional Comparators](http://discourse.iapct.org/t/bidirectional-comparators/16054)
**Author:** [@rsmarken](http://discourse.iapct.org/u/rsmarken)\ **Replies:** 6\ **Last updated:** [June 6, 2023, 3:38am UTC](http://discourse.iapct.org/t/bidirectional-comparators/16054 "2023-06-06T03:38:57Z")
Warren Mansell posted a reference to Erling Jorgensen’s paper in Living Control Systems IV on “How the brain gets a roaring campfire: Thalamus through a PCT microscope”. I took a look at the chapter and noticed that ther… --- ## [Clarification of Perceptual Levels](http://discourse.iapct.org/t/clarification-of-perceptual-levels/16039)
**Author:** [@Evadeh](http://discourse.iapct.org/u/Evadeh)\ **Replies:** 4\ **Last updated:** [May 25, 2023, 2:16pm UTC](http://discourse.iapct.org/t/clarification-of-perceptual-levels/16039 "2023-05-25T14:16:56Z")
Invitation to take part in study to clarify perceptual levels Dear members of the IAPCT forum, I would like to invite you to take part in this study that my student, Lisa Kuijf is undertaking to try to define and opera… --- ## [Essentials of PCT](http://discourse.iapct.org/t/essentials-of-pct/16026)
**Author:** [@rsmarken](http://discourse.iapct.org/u/rsmarken)\ **Replies:** 10\ **Last updated:** [February 22, 2023, 10:52pm UTC](http://discourse.iapct.org/t/essentials-of-pct/16026 "2023-02-22T22:52:42Z")
Continuing the discussion from Where Rick's Chapter 7 on "Social Control" goes off track: I think that’s a great idea. Perhaps approaching this that way can keep these posts a lot shorter. And since it’s no longer abou… --- ## [Paradigm Lost...(and Regained?)](http://discourse.iapct.org/t/paradigm-lost-and-regained/16014)
**Author:** [@rsmarken](http://discourse.iapct.org/u/rsmarken)\ **Replies:** 16\ **Last updated:** [January 30, 2023, 11:01pm UTC](http://discourse.iapct.org/t/paradigm-lost-and-regained/16014 "2023-01-30T23:01:45Z")
This is my attempt to explain why the discussion of the power law of movement is important, to me anyway. It is because the disagreement about how to explain the power law illustrates why PCT has had – and continues to h… --- ## [Error signals or perceptual signals upward and downward in the hierarchy](http://discourse.iapct.org/t/error-signals-or-perceptual-signals-upward-and-downward-in-the-hierarchy/15992)
**Author:** [@Evadeh](http://discourse.iapct.org/u/Evadeh)\ **Replies:** 23\ **Last updated:** [January 18, 2023, 7:33pm UTC](http://discourse.iapct.org/t/error-signals-or-perceptual-signals-upward-and-downward-in-the-hierarchy/15992 "2023-01-18T19:33:33Z")
Dear colleagues, There is a question that has been bugging me and maybe it’s something that one of you has thought about so please share your thoughts. I’m just reading in my students’ thesis that an important assumpti… --- ## [Ramifications of collective control](http://discourse.iapct.org/t/ramifications-of-collective-control/15993)
**Author:** [@bnhpct](http://discourse.iapct.org/u/bnhpct)\ **Replies:** 53\ **Last updated:** [December 13, 2022, 2:17pm UTC](http://discourse.iapct.org/t/ramifications-of-collective-control/15993 "2022-12-13T14:17:30Z")
Not everyone is interested in exploring the limitations and possibilities of control theory. This is a basis, I think, of the long-running disagreements between Rick and Martin, exemplified by a failure to come to mutual… --- ## [Einstein on the blind isms and the elephant](http://discourse.iapct.org/t/einstein-on-the-blind-isms-and-the-elephant/15994)
**Author:** [@bnhpct](http://discourse.iapct.org/u/bnhpct)\ **Replies:** 0\ **Last updated:** [December 3, 2022, 7:04pm UTC](http://discourse.iapct.org/t/einstein-on-the-blind-isms-and-the-elephant/15994 "2022-12-03T19:04:31Z")
I recently acquired a copy of my friend Tom Ryckman’s marvelous book Einstein. I think I will be recommending it. A bit about Tom. After he completed his 1986 dissertation at Columbia (of which chapters 7 and 8 are of p… --- ## [Autonomy and evolution](http://discourse.iapct.org/t/autonomy-and-evolution/15991)
**Author:** [@MartinT](http://discourse.iapct.org/u/MartinT)\ **Replies:** 26\ **Last updated:** [November 27, 2022, 6:34pm UTC](http://discourse.iapct.org/t/autonomy-and-evolution/15991 "2022-11-27T18:34:20Z")
For a few days, I have been puzzling over what “autonomy” implies. For me, the problem has to be the degree to which designed robots could be autonomous in the way that Asimov’s robots subject to his three laws about har… --- ## [Epistemology, perception and reality](http://discourse.iapct.org/t/epistemology-perception-and-reality/15923)
**Author:** [@amatic](http://discourse.iapct.org/u/amatic)\ **Replies:** 8\ **Last updated:** [November 20, 2022, 7:40pm UTC](http://discourse.iapct.org/t/epistemology-perception-and-reality/15923 "2022-11-20T19:40:05Z")
Epistemology, or the theory of the origin and limits of knowledge, comes up quite often on CSGnet, and it looks like there are many different opinions. I’ve found that expressing the variables ans functions in mathematic… --- ## [Side Effects of Control](http://discourse.iapct.org/t/side-effects-of-control/15957)
**Author:** [@rsmarken](http://discourse.iapct.org/u/rsmarken)\ **Replies:** 44\ **Last updated:** [October 11, 2022, 1:56am UTC](http://discourse.iapct.org/t/side-effects-of-control/15957 "2022-10-11T01:56:45Z")
One of the first papers I published on what is now called PCT (when I still hadn’t mastered the “that-which” distinction, I’m afraid) was about distinguishing intentional from accidental behavior. What I called “accident… --- ## [You think your constructivism is radical](http://discourse.iapct.org/t/you-think-your-constructivism-is-radical/15967)
**Author:** [@bnhpct](http://discourse.iapct.org/u/bnhpct)\ **Replies:** 0\ **Last updated:** [October 10, 2022, 12:10am UTC](http://discourse.iapct.org/t/you-think-your-constructivism-is-radical/15967 "2022-10-10T00:10:22Z")
Try this video discussion by physicist Vlatko Vedral ‘on the shoulders of Everett’. The reference is to Hugh Everett, (1930-1982), originator of the many worlds interpretation of quantum physics, scorned during his life… --- ## [Collaboration of modeler and programmer](http://discourse.iapct.org/t/collaboration-of-modeler-and-programmer/15966)
**Author:** [@bnhpct](http://discourse.iapct.org/u/bnhpct)\ **Replies:** 0\ **Last updated:** [October 9, 2022, 11:53pm UTC](http://discourse.iapct.org/t/collaboration-of-modeler-and-programmer/15966 "2022-10-09T23:53:56Z")
This video of Bill was made at the meeting in Durango in 1994. The first half encapsulates the essentials of PCT. In the first part of that, Bill describes two stages. First, the diagrams that represent a model of what y… --- ## [The Test for the Controlled Variable](http://discourse.iapct.org/t/the-test-for-the-controlled-variable/134)
**Author:** [@bnhpct](http://discourse.iapct.org/u/bnhpct)\ **Replies:** 38\ **Last updated:** [August 26, 2022, 7:41pm UTC](http://discourse.iapct.org/t/the-test-for-the-controlled-variable/134 "2022-08-26T19:41:24Z")
The core methodology of PCT is The Test for the Controlled Variable (or “for the Controlled Quantity”) . “The Test” has been described in a number of places, but questions and requests for clear definition still recur in… --- ## [Program control and control of a Program](http://discourse.iapct.org/t/program-control-and-control-of-a-program/15951)
**Author:** [@bnhpct](http://discourse.iapct.org/u/bnhpct)\ **Replies:** 5\ **Last updated:** [July 28, 2022, 5:40am UTC](http://discourse.iapct.org/t/program-control-and-control-of-a-program/15951 "2022-07-28T05:40:43Z")
There has been a sporadic discussion as to what is controlled at the Program level, e.g. in 1994 and 2009. Rick’s ‘Program control’ demo updates his 2004 proposal. This exemplifies the view that ‘program control’ is cont… --- ## [Shunning and reorganization](http://discourse.iapct.org/t/shunning-and-reorganization/15949)
**Author:** [@bnhpct](http://discourse.iapct.org/u/bnhpct)\ **Replies:** 0\ **Last updated:** [July 22, 2022, 2:31pm UTC](http://discourse.iapct.org/t/shunning-and-reorganization/15949 "2022-07-22T14:31:26Z")
The following passage is on p. 5 of Warren’s recent paper on consciousness Mansell, W. (2022, July 4). An Integrative Control Theory Perspective on Consciousness. Psychological Review. Advance online publication. DOI:1… --- ## [Local memory as habituation of a function?](http://discourse.iapct.org/t/local-memory-as-habituation-of-a-function/15942)
**Author:** [@EetuP](http://discourse.iapct.org/u/EetuP)\ **Replies:** 1\ **Last updated:** [June 21, 2022, 2:23pm UTC](http://discourse.iapct.org/t/local-memory-as-habituation-of-a-function/15942 "2022-06-21T14:23:17Z")
Hi all, This message is a question: “What do you think about memory?” with some introduction. In B:CP memory is defined as: “the storage and retrieval of information carried by neural signals (p. 207)”. In addition it … --- ## [Input Functions are Category Recognizers](http://discourse.iapct.org/t/input-functions-are-category-recognizers/15930)
**Author:** [@MartinT](http://discourse.iapct.org/u/MartinT)\ **Replies:** 17\ **Last updated:** [June 3, 2022, 8:23am UTC](http://discourse.iapct.org/t/input-functions-are-category-recognizers/15930 "2022-06-03T08:23:59Z")
Consider the ancient statement “you never step into the same river twice”. What does that mean, since I “know” that I could step into “Sandy River” on this year’s holiday and again into “Sandy River” on next year’s holid… [Next page](http://discourse.iapct.org/c/research/6.md?page=1)