The problem I was responding to was the resurrection of that old analogy. Unless I just imagined it!
The notion of emergent behaviour if I understand it aright, Robin, is comparable to the emergence of complex systems which I described above. I think it is facetious to tell anyone to read Godel, Escher, Bach -- Hofsteder is NOT readily readable.
From Answers.com:
"Emergence is the process of complex pattern formation from simpler rules. This can be a dynamic process (occurring over time), such as the evolution of the human brain over thousands of successive generations; or emergence can happen over disparate size scales, such as the interactions between a macroscopic number of neurons producing a human brain capable of thought (even though the constituent neurons are not themselves conscious). For a phenomenon to be termed emergent it should generally be unexpected and unpredictable from a lower level description. Usually the phenomenon does not exist at all or only in trace amounts at the very lowest level. Thus, a straightforward phenomenon such as the probability of finding a raisin in a slice of cake growing with the portion-size does not generally require a theory of emergence to explain. It may however be profitable to consider the emergence of the texture of the cake as a relatively complex result of the baking process and the mixture of ingredients.
There is no consensus amongst scientists as to how much emergence should be relied upon as an explanation. It does not appear possible to unambiguously decide whether a phenomenon should be classified as emergent, and even in the cases where classification is agreed upon it rarely helps to explain the phenomena in any deep way. In fact, calling a phenomenon emergent is sometimes used in lieu of any better explanation.
The Principle of Emergence
Emergent properties
An emergent behaviour or emergent property can appear when a number of simple entities (agents) operate in an environment, forming more complex behaviours as a collective. The property itself is often unpredictable and unprecedented, and represents a new level of the system's evolution. The complex behaviour or properties are not a property of any single such entity, nor can they easily be predicted or deduced from behaviour in the lower-level entities. The shape and behaviour of a flock of birds or school of fish are good examples.
One reason why emergent behaviour occurs is that the number of interactions between components of a system increases combinatorially with the number of components, thus potentially allowing for many new and subtle types of behaviour to emerge. For example, the possible interactions between groups of molecules grows enormously with the number of molecules such that it is impossible for a computer to even count the number of arrangements for a system as small as 20 molecules."
Just so we all are using the same vocabulary here!