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GuySrinivasan comments on Controlling your inner control circuits - Less Wrong
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Let me clarify where I do and do not agree with PJ Eby, since we've been involved in some heated arguments that often seem to go nowhere.
I accept that the methods described here could work, and intend to try them myself.
I accept that all of the mechanisms involved in behavior can be restated in the form of a network of feedback loops (or a computer program, etc.).
I accept that Eby is acting as a perfect Bayesian when he says "Liar!" in response to those who claim they "gave it a try" and it didn't work. To the extent that he has a model, that is what it obligates him to believe, and Eliezer Yudkowsky has extensively argued that you should find yourself questioning the data when it conflicts with your model.
So what's the problem, then?
I do not accept that these predictions actually follow from, or were achieved through the insights of, viewing humans as feedback control systems. The explanations here for behavioral phenomena look like commonsense reasoning that is being shoehorned into controls terminology by clever relabeling. (ETA: Why do you need the concept of a "feedback control system" to think of the idea of running through the reasons you're afraid of something, for example?)
For that reason, I ran the standard check to see if a model is actually constraining expectations by asking pjeby what it rules out, and, more importantly, why PCT says you shouldn't observe such a phenomenon. And I still don't have an answer.
(This doesn't contradict my third point of agreement, because pjeby can believe something contradicts his model, even if, it turns out, the model he claims to believe in draws no such conclusion.)
Rather, based on this article, it looks like PCT is in the position of:
"Did PCT Method X solve your problem? Well, that's because it reset your control references to where they should be. Did it fail? Well, that's because PCT says that other (blankly solid, blackbox) circuts were, like, fighting it."
I purchased Behavior: The Control of Perception and am reading it. Unless someone else does so first, I plan to write a review of it for LW. A key point is that at least part of PCT is actually right. The lowest level controllers, such as those controlling tendon tension, are verifiably there. So far as I can see so far, real physical structures corresponding pretty closely to second and third level controllers also exist and have been pointed to by science. I haven't gotten further than this yet, but teasers within the book indicate that (when the book was written of course) there is good evidence that some fifth level control systems exist in particular places in the brain, and thus fourth level somewhere. Whether it's control systems (or something closish to them) all the way up? Dunno. But the first couple levels, not yet into the realm of traditional psychology or whatnot, those definitely exist in humans. And animals of course. The description of the scattershot electrodes in hundreds of cats experiment was pretty interesting. :)
That said, you're absolutely right, there should be some definite empirical implications of the theory. For example due to the varying length of the paths at various supposed levels, it should be possible to devise an experiment around a simple tracking task with carefully selected disturbances which will have one predicted result under PCT and another under some other model. Also, predicting specific discretization of tasks that look continuous should be possible... I have not spent a lot of time thinking about how to devise a test like this yet, unfortunately.
Please add PCT to the wiki as Jargon and link there when this term, whatever it means, is used for the first time in a thread. It is not in the first 10 Google hits.
It seems jimrandomh has taken the time to do so; the wikipedia article should be helpful.
In defense of people using the acronym without definition, though, it seemed fairly obvious if you look at the wikipedia disambig page for the acronym in question.
As a general-purpose prior assumption for systems designed by evolutionary processes, reusing or adapting existing systems is far more likely than spontaneous creation of new systems.
Thus, if it can be demonstrated that a model accurately represents low-level hierarchical systems, this is reasonably good evidence in favor of that model applying all the way to the top levels as opposed to other models with similar explanatory power for said upper levels.