RM: There are physical correlates of all these variables, otherwise we couldn’t control them. But the physical correlates of these variables are not necessarily physical entities. Even the perception of speed doesn’t have a physical correlate as a physical entity. The perception of speed is a calculation based, ultimately, on the change over time in the position of an entity in the environment. If the position of the entity at two points in time is represented as x.t and x.t+tau then the perception of speed could be represented as s = (x.t+tau - x.t)/dt, where dt is the time for x to move tau units of distance. The variable s is the perception of speed, (x.t+tau - x.t)/dt is the perceptual function that produces that perceptual variable and the physical correlates of s are the physical variables that go into the computation of s – x.t+tau, x.t and t (dt is also a perception).
The same holds for honesty and democracy. Both of these perceptual variables are functions of physical variables, like the x and t variables that are the basis of the perception of speed, but the functions that compute these perceptual variables are much more complex than the one that calculates speed. And the physical correlates of variables like honesty and democracy are like those that are the basis of the perception of speed – things like changes in the position of lips (for example, you can tell when Trump is lying because his lips are moving).
[From Bill Powers (961224.1145 MST)]
BP (emphasis mine, RM): As far as the observer is concerned, what is controlled is ONLY the CV. The idea that this CV is represented by a perceptual signal inside the other system is theoretical. We can observe CV, but not p. When we apply a disturbance, we apply it to CV, not to p. The action that opposes the effect of the disturbance acts on CV, not p. The Test does not involve p at all. It involves only observables – i.e., the observer’s perceptions. The observations have priority; the model comes second, and its only reason for existence is to explain the observations. When you fool around with thought-experiments too much, you tend to get the priorities reversed.
RM: Thanks you for posting this. This is what I have been saying over and over again, to something less than deafening applause. But it is essential that one understand this point in order to be able to do PCT- based research.
RM: Here’s the complete interaction from the CSGNet post that included the comments from Bill:
[From Bill Powers (990503.0232 MDT)]
RM: We can observe CVs. If we couldn’t, there would be no need for PCT.
Bruce Abbott: You have never observed a CV in your life. At best, you have observed environmental correlates of them.
BP: It’s the other way around. ALL we can observe of another person’s controlling is the CV; what we can’t observe is the “CP” – the controlled
perception in the other person.
RM: So here is Bill correcting Bruce Abbott rather than me;-) Bill’s (and my) point is one again that controlled variables are perceptions in the observer. They are not physical entities. Controlled variables (such as speed, honesty and democracy) are functions of physical variables. The physical correlates of controlled variables are the bases of the functions that define those variables.
RM: Since the controlled variable, CV or q.i, is exactly equivalent to the theoretical perpetual variable, p – the variable that accounts for the existence of q.i – there is never a question of whether p is an accurate representation of q.i; p and q.i are, by definition, the same variable: q.i = p. As per the title of this topic, controlled variables ARE perceptual variables.
RM: Again, one has to understand this essential fact about PCT – that controlled variables are observations that are explained by the assumption that they are controlled as perceptual signals that are analogs of the observed variable - before one can participate productively in the PCT-based research program that Bill proposed in Powers, 1979