The Architecture of Complexity: Understanding the development and dynamics of the System, Part I

Architecture of complexity

Complexity and hierarchy go hand in hand (illustration: source)

In the publication “The architecture of complexity” (1962), Herbert A. Simon makes some observations concerning the typical structure and dynamics of complex systems.

In three articles, I discuss two questions concerning the development of the System. To answer these questions, I make use of Simon’s perspective on the structure and functioning of complex systems. The two questions are:

(1) How can the phase transition the System experienced during – by means of – the fourth systemic war (the Second World War, 1939-1945) be explained? and (2) What can Simon’s insights in the functioning of complex systems contribute to our understanding of the condition of the current international order and what can – according to Simon’s perspective – now be expected?

In this article I discuss several of Simon’s observations, before discussing these two questions in Part II and III

Before going into more detail, this ‘outline’ could be useful to understand Simon’s theory:

(1) The central theme that runs through Simon’s observations is that complexity frequently takes the form of hierarchy, and that hierarchic systems have some common properties that are independent of  their specific content. Hierarchy, is “one of the central structural schemes that the architect of complexity uses”, Simon argues.

(2) Simon observes that complex systems exhibit (what he calls) “hierarchic structure”; a “complex system being composed of subsystems“. The System – the international order -(consisting of states and communities) also has a hierarchic structure.

(3) Simon argues that a relation exists between the structure of a complex system and the time required for it to emerge through evolutionary process; Simon theorises that “hierarchic systems will evolve far more quickly than non-hierarchic systems of comparable size”. This observation can be used to discuss the question if and how the breakdown of states – failed states – impact on the development of the System toward a non-anarchistic system at a global scale.

(4) Simon observes that hierarchically organised systems can be decomposed into subsystems and that hierarchically organised systems have typical dynamic properties. These properties are helpful in understanding the dynamics of the System, including Europe’s efforts to add an additional hierarchical level to its structure.

Although Simon’s publication is already dated (1962), his observations are not and are still valid, and offer numerous clues to (also) better understand the dynamics and development of the System we live in and are integral parts of.

Herbert Simon, 2

In 1978, Herbert Simon received the Nobel Prize in Economic Sciences.

Simon describes a complex system as a system that is “made up of a large number of parts that interact in a non-simple way. In such systems, the whole is more than the sum of the parts, not in an ultimate, metaphysical sense, but in the important pragmatic sense that, given the properties of the parts and the laws of their interaction, it is not a trivial matter to infer the properties of the whole.

Simon observes that “Empirically, a large proportion of the complex systems we observe in nature exhibit hierarchic structures. On theoretical grounds we could expect complex systems to be hierarchies in a world in which complexity had to evolve from simplicity. In their dynamics, hierarchies have a property, near decomposability, that greatly simplifies their behaviour.”

Hierarchy has in Simon’s framework a somewhat different meaning : Hierarchy does not refer to subordination, but to the structural characteristic of complex systems, the observation that complex systems are often analysable into successive sets of subsystems.

In Simon’s words: “.. the central theme that runs through my remarks is that complexity frequently takes the form of hierarchy, and that hierarchic systems have some common properties that are independent of their specific content. Hierarchy, I shall argue, is one of the central structural schemes that the architect of complexity uses.”

‘Hierarchy’ has a different meaning than how this term is normally used. According to Simon: “Etymologically, the word “hierarchy” has had a narrower meaning than I am giving it here. The term has generally been used to refer to a complex system in which each of the subsystems is subordinated by an authority relation to the system it belongs to. More exactly, in a hierarchic formal organisation, each system consists of a “boss” and a set of subordinate subsystems. Each of the subsystems has a “boss” who is the immediate subordinate of the boss of the system. We shall want to consider systems in which the relations among subsystems are more complex than in the formal organisational hierarchy just described. We shall want to include systems in which there is no relation of subordination among subsystems. (In fact, even in human organisations, the formal hierarchy exists only on paper; the real flesh-and-blood organisation has many interpart relations other than the lines of formal authority.) For lack of a better term, I shall use “hierarchy” in the broader sense introduced in the previous paragraphs, to refer to all complex systems analysable into successive sets of subsystems, and speak of “formal hierarchy” when I want to refer to the more specialised concept.

Simon means by a hierarchic system, or hierarchy, “a system that is composed of interrelated subsystems, each of the latter being, in turn, hierarchic in structure until we reach some lowest level of elementary subsystem. In most systems in nature, it is somewhat  arbitrary as to where we leave off the partitioning and what subsystems we take as elementary. Physics makes much use of the concept of “elementary particle,” although particles have a disconcerting tendency not to remain elementary very long.”

Simon argues that social systems also often have “parts-within-parts” structures: “Almost all societies have elementary units called families, which may be grouped into villages or tribes, and these into larger groupings, and so on. If we make a chart of social interactions, of who talks to whom, the clusters of dense interaction in the chart will identify a rather well-defined hierarchic structure.

A typical property of hierarchic systems (including formal organisations) is their span (span of control in case of formal organisations): Simon speaks of a span of a system, by which he means “the number of subsystems into which it is partitioned.”

Regarding hierarchies Simon furthermore observes: “There is one important difference between the physical and biological hierarchies, on the one hand, and social hierarchies, on the other. Most physical and biological hierarchies are described in spatial terms.

Simon proposes to identify social hierarchies “not by observing who lives close to whom but by observing who interacts with whom. These two points of view can be reconciled by defining hierarchy in terms of intensity of interaction, but observing that in most biological and physical systems relatively intense interaction implies relative spatial propinquity. One of the interesting characteristics of nerve cells and telephone wires is that they permit very specific strong interactions at great distances. To the extent that interactions are channelled through specialised communications and transportation systems, spatial propinquity becomes less determinative of structure.

Simon in his essay focuses on the evolution of complex systems. Regarding this subject, Simon observes that “The time required for the evolution of a complex form from simple elements depends critically on the numbers and distribution of potential intermediate stable forms.” and that “direction of development of the structure of the (at least in some cases) is provided to the scheme by the stability of the complex forms, once these come into existence. But this is nothing more than survival of the fittest— i.e., of the stable.

According to Simon ‘fitness’ (and survival changes) and ‘stability’ are related.

Simon observes, regarding the evolutionary explanation of hierarchic structures: “We have shown thus far that complex systems will evolve from simple systems much more rapidly if there are stable intermediate forms than if there are not. The resulting complex forms in the former case will be hierarchic. We have only to turn the argument around to explain the observed predominance of hierarchies among the complex systems nature presents to us. Among possible complex forms, hierarchies are the ones that have the time to evolve. The hypothesis that complexity will be hierarchic makes no distinction among very flat hierarchies, like crystals and tissues and polymers, and the intermediate forms. Indeed, in the complex systems we encounter in nature, examples of both forms are prominent. A more complete theory than the one we have developed here would presumably have something to say about the determinants of width of span in these systems.

The next concept Simon introduces in his essay is the concept of “nearly decomposable systems“: “In hierarchic systems, we can distinguish between the interactions among subsystems, on the one hand, and the interactions within subsystems— i.e., among the parts of those subsystems—on the other. The interactions at the different levels may be, and often will be, of different orders of magnitude. In a formal organisation there will generally be more interaction, on the average, between two employees who are members of the same department than between two employees from different departments. In organic substances, intermolecular forces will generally be weaker than molecular forces, and molecular forces weaker than nuclear forces.

Based on the forces between parts of a system, Simon distinguishes between systems that are decomposable into subsystems comprised of the individual parts, and nearly decomposable systems, “in which the interactions among the subsystems are weak, but not negligible.” Simon argues: “At least some kinds of hierarchic systems can be approximated successfully as nearly decomposable systems. The main theoretical findings from the approach (Simon discusses in the essay) can be summed up in two propositions: (a) in a nearly decomposable system, the short-run behaviour of each of the component subsystems is approximately independent of the short-run behaviour of the other components; (b) in the long run, the behaviour of any one of the components depends in only an aggregate way on the behaviour of the other components.

Furthermore, Simon observes: “In the dynamics of social systems, where members of a system communicate with and influence other members, near decomposability is generally very prominent”. This implies – as Simon argues – that because many social systems (including states, I argue) are nearly-decomposable, the short-run dynamics relate to the internal structures of the subsystems (states), the long-run dynamics to interactions between these subsystems (states).

Simon points to the practicality of hierarchical structures (which also helps explain the evolutionary advantage of these types of systems: evolving complexity tends to be hierarchic): “In studying the interaction of two nations, we do not need to study in detail the interactions of each citizen of the first with each citizen of the second. The fact, then, that many complex systems have a nearly decomposable, hierarchic structure is a major facilitating factor enabling to us understand, to describe, and even to ‘see’ such systems and their parts. Or perhaps the proposition should be put the other way round. If there are important systems in the world that are complex without being hierarchic, they may to a considerable extent escape our observation and our understanding. Analysis of their behaviour would involve such detailed knowledge and calculation of the interactions of their elementary parts that it would be beyond our capacities of memory or computation.

Simon Summarises his observations regarding near decomposability as follows:  “We have seen that hierarchies have the property of near decomposability. Intracomponent linkages are generally stronger than intercomponent linkages. This fact has the effect of separating the high-frequency dynamics of a hierarchy – involving the internal structure of the components – from the low-frequency dynamics – involving interaction among components.

As I will discuss in the next two parts of this series, Simon’s observations offer valuable clues to better understand the dynamics and the development of the System, and the current international order.

To be continued.