I've just received a preparation pack for the SPARK workshop, including a new copy of Christopher Alexander's book Timeless Way of Building, first published in 1979. I wonder how many of the SPARK participants have looked at Alexander's later material, including his New Theory of Urban Design (1987), and his magnificent new 4-volume work The Nature of Order.
Here are some of the themes of Alexander's thinking that I see as particularly relevant to SOA.
1. Under the right conditions, complex order emerges from a series of simple steps. A given structure at a given moment is in a partially evolved state.
2. Each step is generally structure-preserving - it builds upon the differentiation and coherence (strength) of the existing structure.
3. Each step brings greater differentiation and greater coherence (strength). Alexander calls this the Fundamental Differentiating Process. (See Nature of Order, Book 2, page 216).
4. Alexander defines structure in terms of a network of centres. Alexander's notions of structure-preservation, differentiation and coherence are explained in terms of this notion of structure. (See "Centers: The Architecture of Services and the Phenomenon of Life," FTPOnline, Richard C. Murphy, March 2004)
5. A key role of governance is then to establish and maintain the conditions under which this fundamental differentiating process can work. (See my articles in the Architecture Journal: Metropolis and SOA Governance and Taking Governance to the Edge).
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