# History of Ideas (was Re: Latash, 2010: "Motor Control Theories and Their Applications")

**URL:** <http://discourse.iapct.org/t/history-of-ideas-was-re-latash-2010-motor-control-theories-and-their-applications/5264>\
**Category:** CSG2013\
**Created:** [December 30, 2013, 4:44am UTC](http://discourse.iapct.org/t/history-of-ideas-was-re-latash-2010-motor-control-theories-and-their-applications/5264 "2013-12-30T04:44:26Z")\
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**Author:** ![MartinT](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/m/ee7513/32.png) [@MartinT](http://discourse.iapct.org/u/MartinT)\
**Post date:** [December 30, 2013, 4:44am UTC](http://discourse.iapct.org/t/history-of-ideas-was-re-latash-2010-motor-control-theories-and-their-applications/5264/1 "2013-12-30T04:44:26Z")

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[Martin Taylor 2013.12.29.23.12]

```
Mackay's paper is targeted at an explanation of the perception that

```

we have free will despite being physical beings constrained by  
physical laws. The first half, however, is devoted to building a  
background for his argument. That background is the surprise. In it, he describes what appears to  
be exactly the Latash et al. model so far as I understand both  
Mackay and Latash et al., but he uses it only as the lowest level  
component in a hierarchic control structure. Mackay describes the  
lowest two levels and says effectively “and so on”, each level  
providing reference values for the inputs from lower levels. It is  
pure PCT, despite that the paper title seems to say otherwise:  
“Cerebral Organization and the Conscious Control of Action”. The  
diagrams and text make clear that it is input that is controlled. He  
explicitly rejects the concept of predetermined cancellation of  
error-producing disturbances, and the specification of output  
values.  
So far as I know, Mackay never developed this idea. At least, I  
don’t think he ever spoke to me about it during my Sabattical year  
at Keele. The main point of the paper was to deduce a logical  
consequence of the structure. He says that if the hierarchic  
closed-loop structure exists, then “it is impossible in principle to  
deduce, from the prior state of the world including the agent’s  
brain, a prediction of his choice on which agent and observer would  
be right to agree. … In this sense typical human choices would be  
‘logically indeterminate’ even if the flow system that mediated them  
were physically determinate.” I imagine that it was only in this context that Mackay saw the  
hierarchic control structure as important. To me, that puts Mackay  
among those who had the background and opportunity to see the power  
of PCT, but who missed Bill Powers’ insight of genius, that it  
really matters. Be that as it may, I find it interesting in the  
present context that back in 1955 Mackay put the Latash structure in  
the context of a explicit two-level control system in which the  
upper level provides the reference value for the lower level. Reference: Mckay, D.M., Cerebral Organization and the Conscious  
Control of Action, Pontificiae Academiae Scientiarum Scripta Varia,  
30, 1955, 627-663.  
Martin

> **···**
>
> In 1966-7 I had a Sabbatical at Keele University in England at the  
> invitation of Donald Mackay. Today, I came across an old paper  
> reprint of a 1955 presentation by him at a Symposium apparently on  
> the cerebral basis of consciousness. He must have given it to me  
> in person along with others of his reprints. I haven’t seen this  
> one for ages, and quite probably have never read it before now. At  
> least I don’t remember having seen it. As you will see, this is  
> relevant to the Latash thread.
> 
> > [From Rick Marken (2013.12.29.1600)]
> > 
> > ```
> > > Bruce Abbott (2013.28.1745 EST)--
> > 
> > ```
> > 
> > > ```
> > > >BA: I've been doing some on-line reading of the
> > > 
> > > ```
> > > 
> > > literature on the equilibrium point (EP) model and can see why  
> > > Latash et al. would not be aware of any connection of their  
> > > model with PCT.
> > 
> > ```
> > RM: It's not that they are "not aware" of a connection; they
> > 
> > ```
> > 
> > explicitly _reject_ a connection because they reject control  
> > theory.
> > 
> > > ```
> > > >
> > > 
> > > ```
> > > 
> > > BA: In fact, I’ve found it difficult to understand their  
> > > model, given the descriptions I’ve read of it. Thus far I have  
> > > not seen a discussion of how the “commands” of the system are  
> > > derived; it could very well be an open-loop system at that  
> > > level, or maybe not.
> > 
> > ```
> > RM: I'm pretty sure it's an open loop model. Their "commands"
> > 
> > ```
> > 
> > are not like reference signals because they not specifications  
> > for input. Rather, they are commands for output – they cause  
> > the tensions in the muscles (outputs) that determine the  
> > equilibrium point of the limbs to which the muscles are  
> > attached.