Alexander and Cybernetics
“Scientists try to identify the components of existing structures, designers try to shape the components of new structures.”
— Christopher Alexander, 1964
“This is what lies behind D’ Arcy Thompson’s remark that the form is a diagram of forces. Once we have the diagram of forces in the literal sense, this will in essence also describe the form as a complementary diagram of forces.”
— Christopher Alexander, 1964
This systemic approach is directly influenced by Cybernetics and specifically Norbert Wiener and Ross Ashby’s homeostasis theory.
In Alexander’s case, systems are used to describe an environmental approach to design, which conceives our habitat as an open system of animate and inanimate agents (Maldonado, 1969) and design knowledge is approached holistically as the man-environment relationship.
Due to his continuous effort to describe design as a diagram of forces that and his participation in Design Methods Conference, his name is associated to the nascent field of Design Methods. However, later in his life, he denounces the whole field:
“Indeed, since the book was published (Notes on the Synthesis of form, 1964), a whole academic field has grown up around the idea of “design methods”-and I have been hailed as one of the leading exponents of these so-called design methods. I am very sorry that this has happened, and want to state, publicly, that I reject the whole idea of design methods as a subject of study, since I think it is absurd to separate the study of designing from the practice of design. […] Study of method by itself is always barren, and people who have treated this book as if it were a book about “design method” have almost always missed the point of the diagrams, and their great importance, because they have been obsessed with the details of the method I propose for getting at the diagrams.”
— Christopher Alexander, 1971
Hierarchical Decomposition of Systems (HIDECS)
Tree Structure and HIDECS 2
In his dissertation Notes on the synthesis of Form, Alexander describes design problem as sets that can be in a hierarchical tree. The computer program HIDECS 2 that corresponds to this theory uses a binary stochastic algorithm that “at each level of the tree each set of variables is broken into those two subsets with minimum information transfer between them”. Alexander realizes that this method does not take into account the holistic relatedness of system and subsystems. Usually subsystems overlap in a system.
Lattice Structures and HIDECS 3
Since his realization that structural interrelations cannot always be described as trees, he writes the City is not a Tree and HIDECS 3 that aims to tackle weaknesses of HIDECS 2, while using the same “machine representation”. He therefore introduces the structure of the semi lattice. In this program the decomposition into subsystems is not defined by a binary condition in each step, but all at once.
Later on, Alexander will write collaboratively Pattern Language, his most famous work, where he looses his control on information structures and describes systems as open networks. Patterns contain information of the forces that made them but they are at the same time instances of an open-ended approach to design.
“Each pattern is a field — not fixed, but a bundle of relationships, capable of being different each time that it occurs, yet deep enough to bestow life wherever it occurs.”