More Notes on Constraints in Cybernetics:

In today’s post, I am looking further at constraints. Please see here for my previous post on this. Ross Ashby is one of the main pioneers of Cybernetics, and his book “Introduction to Cybernetics” still remains an essential read for a cybernetician. Alicia Juarrero is a Professor Emerita of Philosophy at Prince George’s Community College (MD), and is well known for her book, “Dynamics in Action: Intentional Behavior as a Complex System”.

I will start off with the basic idea of a system and then proceed to complexity from a Cybernetics standpoint. A system is essentially a collection of variables that an observer has chosen to make sense of something. Thus, a system is a mental construct and not something that is an objective reality. A system from this standpoint is entirely contingent upon the observer. Ashby’s view on complexity was regarding variety. Variety is the number of possible states of a system. A good example of this is a light switch. It has two states – ON or OFF. Thus, we can state that a light switch has a variety of 2. Complexity is expressed in terms of variety. The higher variety a system has, the more possibilities it possesses. A light switch and a person combined has indefinite variety. The person is able to communicate via messages simply by turning the light switch ON and OFF in a certain logical sequence such as Morse code.

Now let’s look at constraints. A constraint can be said to exist when the variety of a system is said to have diminished or decreased. Ashby gives the example of a boys only school. The variety for sex in humans is 2. If a school has a policy that only boys are allowed in that school, the variety has now decreased to 1 from 2. We can say that a constraint exists at the school.

Ashby indicated that we should be looking at all possibilities when we are trying to manage a situation. Our main job is to influence the outcomes so that certain outcomes are more likely than others. We do this through constraints. Ashby noted:

The fundamental questions in regulation and control can be answered only when we are able to consider the broader set of what it (system) might do, when ‘might’ is given some exact specification.

We can describe what we have been talking about so far with a simple schematic. We can try to imagine the possible outcomes of the system when we interact with it and utilize constraints so that certain outcomes, P2 and P4 are more likely to occur. There may be other outcomes that we do not know of or can imagine. Ashby advises that cybernetics is not about trying to understand what a system is, but what a system does. We have to imagine a set of all possible outcomes, so that we can guide or influence the system by managing variety. The external variety is always more than the internal variety. Therefore, to manage a situation, we have to at least match the variety of the system. We do this by attenuating the unwanted variety and by amplifying our internal variety so that we can match the variety thrown at us by the system. This is also represented as Ashby’s Law of Requisite Variety – only variety can absorb variety. Ashby stated:

Cybernetics looks at the totality, in all its possible richness, and then asks why the actualities should be restricted to some portion of the total possibilities.

Ashby talked about several versions of constraints. He talked about slight and severe constraints. He gave an example of a squad of soldiers. If the soldiers are asked to line up without any instructions, they have maximum freedom or minimum constraints to do so. If the order was given that no man may stand next to a man whose birthday falls on the same day, the constraint would be slight, for of all the possible arrangements few would be excluded. If, however, the order was given that no man was to stand at the left of a man who was taller than himself, the constraint would be severe; for it would, in fact, allow only one order of standing (unless two men were of exactly the same height). The intensity of the constraint is thus shown by the reduction it causes in the number of possible arrangements.

Another way that Ashby talked about constraints was by identifying constraint in vectors. Here, multiple factors are combined in a vector such that the resultant constraint is considered. The example that Ashby gave was that of an automobile. He gave the example of the vector shown below:

(Age of car, Horse-power, Color)

He noted that each component has a variety that may or may not be dependent on the other components. If the components are dependent on each other the final constraint will be less than the sum of individual component constraints. If the components are all independent, then the resultant constraints would be the sum of individual constraints. This is an interesting point to further look at. Imagine that we are looking at a team here of say Person A, B and C. Each person here is able to come up with indefinite possibilities, the resultant variety of the team would be also indefinite. If we allow for the indefinite possibilities to emerge, as in innovation or invention of new ideas or products, the constraints could play a role. When we introduce thinking agents to the mix, the number of possibilities goes up.

Complexity is about managing variety – about allowing room for possibilities to tackle complexity. Ashby famously noted that a world without constraints is totally chaotic. His point is that if a constraint exists, it can be used to tackle complexity. Allowing parts to depend upon each other introduces constraints that could cut down on unwanted variety and at the same time allow for innovative possibilities to emerge. The controller’s goal is to manage variety and allow for certain possible outcomes to be more likely than others. For this, the first step to imagine the total set of possible outcomes to best of their abilities. This means that the controller also has to have a good imagination and creative mind. This points to the role of the observer when it comes to seeing and identifying the possibilities. Ashby referred to the set of possibilities as “product space.” Ashby noted that its chief peculiarity is that it contains more than actually exists in the real physical world, for it is the latter that gives us the actual, constrained subset.

The real world gives the subset of what is; the product space represents the uncertainty of the observer. The product space may therefore change if the observer changes; and two observers may legitimately use different product spaces within which to record the same subset of actual events in some actual thing. The “constraint” is thus a relation between observer and thing; the properties of any particular constraint will depend on both the real thing and on the observer. It follows that a substantial part of the theory of organization will be concerned with properties that are not intrinsic to the thing but are relational between the observer and thing.

A keen reader might be wondering how the ideas of constraints stack up against Alicia Juarrero’s versions of constraints. More on this in a future post.  I will finish with a wonderful tribute to Ross Ashby from John Casti:

The striking fact is that Ashby’s idea of the variety of a system is amazingly close to many of the ideas that masquerade today under the rubric “complexity.”

Please maintain social distance and wear masks. Please take vaccination, if able. Stay safe and Always keep on learning… In case you missed it, my last post was Towards or Away – Which Way to Go?

6 thoughts on “More Notes on Constraints in Cybernetics:

  1. It all makes much more sense to me when I replace the word system, with the word model and Ashby’s school analogy hasn’t aged well. Love that quote from John Casti with ‘rubric’ very clever and I’m looking forward to your Juarrero connection.

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  2. Dear Harish,
    Your today post on Constraints in Cybernetics brings me back to your previous post (here) where you have briefly addressed the effect of the observer “The observer brings and applies internal constraints on the external world”. I’m a bit sorry you do not highlight the role of internal constraints in your today post. The internal constraints of the observer applied to the external world are sources of meanings within the observer, and these meanings can be used to initiate actions for the satisfaction of the internal constraints.
    Also, internal constraints lead to define an agent as “an identifiable entity submitted to internal constraints and capable of actions for the satisfaction of the constraints”. And also to define an autonomous agent as “a system able to act to satisfy its internal constraints by its own”. This can apply to living entities and to artificial agents as well. If you are interested there is a short paper on this at: https://philpapers.org/archive/MENITA-7.pdf. If you have more time, you can have a look at https://philpapers.org/rec/MENCSA-2.

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