Jordan and the Systems Taxonomy

In an essay from 1968 published in Themes in Speculative Psychology an American psychologist, Nehemiah Jordan, presented his Systems Taxonomy. As a non-hierarchial structure it will only in part fulfil the conditions for being a general systems theory (see p. 53).

Systems taxonomy has three basic organizing principles which enable an observer to define a system as an ‘interaction between what is out there and how we organize it in here’: rate of change, purpose and connectivity. Each principle defines two antitheses of the other, thereby giving three pairs of properties.

Something which does not change within a defined time span (no rate of change) is structural or static; that which does change is functional or dynamic. Quite naturally, the actual time span determines which of the two qualities is relevant to use. In a very short time span, the dynamics are concealed, giving a static impression; in a very long time span, nothing can be static and the structure changes through entropy.

The organizing principle of purpose can generally have two directions: one towards the system itself and one towards the environment. Directed towards the system, the aim is to maintain homeostasis. Directed towards the environment, the aim is often to modify it to resemble a desired state or, if this is not possible, to bypass or override the disturbances.

According to Jordan, the concept of purpose is manifested by systems throughput. Every system whose input is internally processed and transformed to an output, is purposive. The output of the system is the desired goal; man-made systems are thus purposive. There are non- purposive systems as well: physical systems when in equilibrium (for example a volcano) provide an illustration.

Systems obeying the principle of connectivity can be assigned to either of two alternatives: the not densely connected or mechanistic and the densely connected or organismic. If an intervention into a system, with removal of parts and breaking of connections, produces no change of the remaining components, it is classified as mechanistic. In an organismic system the change of a single connection affects all others. A recapitulation is outlined in Table 3.4.

An analysis combining these principles and the pairs of properties gives eight alternatives. Jordan has arranged and exemplified these in the following order.

The overall meaning of Jordan’s Systems Taxonomy is to play down and simplify the often-misused concept of a system. Jordan states that ‘the only things that need to be common to all systems are identifiable entities and identifiable connections between them. In all other ways systems can vary unlimitedly.’ Concepts like feedback systems or self- organizing systems create more confusion than they solve and do not belong to his systems thinking. Finally, Jordan analyzes fifteen different definitions of the word system found in Webster’s New International Dictionary. The result is that every one of the definitions is given its proper place in the taxonomy. Music, for instance as a system of sounds is defined in the dictionary as ‘(1) An interval regarded as a compound of two lesser ones — so used in Byzantine music. (2) A classified series of tones, as a mode or scale. (3) The collection of staffs which form a full score.’ As a time-bound, functional system music fits alternative 7 above.

That music should be non-purposive highlights a major weakness of the taxonomy: the composer has a purpose, so do his listeners. Jordan ascribes the purpose (or its absence) to the system itself, leaving out its creator or observer. Should not a road network then be classified as non- purposive, just like a mountain range?

Source: Skyttner Lars (2006), General Systems Theory: Problems, Perspectives, Practice, Wspc, 2nd Edition.

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