By Srinivas Yermal
Friday, March 29, 2002
Notes On The Synthesis Of Form
By Christopher Alexander, 1971
In the preface, christopher says "... the idea that you can create abstract patterns by studying the implication of limited system of forces, and can create new forms by free combination of these patterns- and realize that this will only work if the patterns which you define deal with systems of forces whose internal interaction is very dense, and whose interaction with the other forces in the world is very weak-then, in the process of trying to create such diagrams or patterns for yourself, you will reach the central idea which this book is all about."
(not the method which leads to the creation of the diagrams, but the diagrams themselves)
Every design problem begins with an effort to achieve fitness betweens two entities: the form in question and its context. The form is the solution to the problem; the context defines the problem. Good fit is a desired property of this ensemble of form and context."First, the taking in of scattered particulars under one idea, so that everyone understands what is being talked about... second, the separation of the Idea into parts, by dividing it at the joints, as nature directs, not breaking any limb in half as a bad carver might."
- Plato, Phaedrus, 265 A.D
If we divide an ensemble into form and context, the fit between them may be regarded as an orderly condition of the ensemble, subject to disturbance in various ways, each one a potential misfit. The state of each potential misfit is represented by means of a binary variable, 0 meaning that there is no misfit occuring. The task of design is not to create form which meets certain conditions, but to create such an order in the ensemble that all the variables take the value 0. The form is simply that part of the ensemble over which we have control. It is only through the form that we can create order in the ensemble.
If there is active stability in the ensemble then the form will always be in good fit, how many ever misfits it encounters.The selfconcious design procedure provides no structural correspondence between the problem and the means devised for solving it. The complexity of the problem is never fully disentangled, and the forms produced not only fail to meet their specifications as fully as they should, but also lack the formal clarity which they would have if the organization of the problem they are fitted to were better understood.
Where a number of issues are being taken into account in a design decision, inevitably the ones whichh can be most clearly expressed carry the greatest weight, and are best reflected in the form, while other factors, important too but less well expressed, are not so well reflected. Unfortunately, although every problem has its own structure, and there are many different problems, the words we have available to describe the components of these problems are generated by forces in the language, not by the problems, and are therefore rather limited in number and cannot describe more than a few cases correctly. For example take the concept of "safety". As far as its meaning is concerned it is relevant to both, a highway or a tea kettle. But as far as the individual structure of the problems goes, it seems unlikely that the one word should successfully identify a principal component subsystem in each of these two very dissimilar problems.Program
Problem here is that we wish to design clearly conceived forms which are well adapted to some given context and for this to be feasible, the adaptation must take place independently within the independent subsystems of variables.Three possible schemes of design process-
- Unselfconcious process - The process which shapes the form is a complex two-directional interaction between the context and the form in the world itself. The human is only present as an agent in this process. He reacts to misfits by changing them; but is unlikely to impose any "designed" conception of the form.
- The selfconcious process - Form is shaped not by interaction between the actual context's demands and the actual inadequacies of the form, but by a conceptual interaction between the conceptual picture of the context which the designer has learned and invented, on the one hand, and ideas and diagrams and drawings which stand for forms, on the other.
- Improvement to the second scheme is to make a further abstract picture of our first picture of the problem, which eradicates its bias and retains only its abstract structural features; this second picture may then be examined according to precisely defined operations, in a way not to subject to the bias of language and experience.
- M - set of misfits (Misfit is a condition of the ensemble as a whole, which comes from the unsatisfactory interaction of the form and the context)
- L - set of links (non-directional signed one-dimensional elements) that describe how the misfits interact.
- G(M, L) - the graph that defines the problem.
The starting point of analysis is the requirement. The end product of analysis is a program, which is a tree of sets of requirements. The starting point of synthesis is a diagram. The end product of synthesis is the realization of the problem, which is a tree of diagrams. Any pattern which, by being abstracted from a real situation, conveys the physical influence of certain demands or forces is a diagram. A diagram is constructive iff it is a requirement diagram (say a mathemetical statement for a race car design) and a form diagram (the water colour perspective view of the car) at the same time.
A good designer invents a form that penetrates the problem so deeply that it not only solves it but illuminates it.The elements of M must have the following properties -
- To be of equal scope
- To be as independent of one another as is reasonably possible
- To be as small in scope and hence as specific and detailed and numerous as possible
Given any partition Pi of a set S into subsets S1, S2.... Sn, we may establish a measure of information transfer or informational dependence among these subsets called R(Pi). The desirable partition of M is one where R(Pi) is minimum.
The Properties of the program -- The tree is, in its hierarchical form, the same as any other hierarchy of concepts - except that the concepts are here defined extensionally, rather than intensionally by meaning.
- The particular tree arrived at by the method outlined gives an explicit description of the structure implicitly responsible for the success and stability of the unselfconscious form-making process.
- The tree gives the strongest possible decomposition of the problem that does not interfere with the task of synthesizing its parts in a unified way. Each subsidiary problem it defines has its own integrity, and is as independent as it can be of the rest of the problem.
- The constructive diagram for the set S should do two things
As a requirement diagram:- It must bring out just those features of the problem which are relevant to this set of requirements.
- It must include no information which is not explicitly called for by these requirements.
As a form diagram:- It must be so specific that it has all physical characteristics called for by the requirements of S.
- Yet it must be so general that it contains no arbitrary characteristics, and so summarizes, abstractly, the nature of every form which might satisfy S.
Every aspect of a form, whether piecelike or patternlike, can be understood as a structure of components. Every object is a hierarchy of components, the large ones specifying the pattern of distribution of the smaller ones, the small ones themselves, though at first sight more clearly piecelike, in fact again patterns specifying the arrangement and distribution of still smaller components.
Every component has this twofold nature: it is first a unit, and second a pattern, both a pattern and a unit (the nature of light and EM waves). Its nature as a unit makes it an entity distinct from its surroundings. Its nature as a pattern specifies the arrangement of its own component units. It is the culmination of the designer's task to make every diagram both a pattern and a unit. As a unit it will fit into the hierarchy of larger components that fall above it; as a pattern it will specify the hierarchy of smaller components which it itself is made of.Hierarchy achieves economy of thought. The right way is the residue when all the wrong ways are eradicated. No attempt is made to formulate abstractly just what the right way involves in the unselfishness conscious.
"The timeless way"
It is a process which brings order out of nothing but ourselves, it cannot be attained but it will happen on its own accord, if we will only let it.
