1996/10/08 Christopher Alexander, “Patterns in Architecture”, OOPSLA ’96
Christopher Alexander’s presentation at the 1996 OOPSLA Conference was lightly edited in the 1999 article. Watching the video and reading the text, the divergences are small until 46 minutes into 63-minutes, when the text was significantly rewritten.
The digest maps the published 1999 article to the 1996 presentation on video.
- Alexander, Christopher. 1996. “Patterns in Architecture” presented at OOPSLA ’96, October 8, San Jose, California. https://www.youtube.com/watch?v=98LdFA-_zfA.
- Alexander, Christopher. 1999. “The Origins of Pattern Theory: The Future of the Theory, and the Generation of a Living World.” IEEE Software, 16 (5): 71–82. doi:10.1109/52.795104. http://dx.doi.org/10.1109/52.795104.
[03:37] In effect, I’m just going to do three things.
1. Pattern Theory. I’m going to talk first of all about patterns and pattern languages, what I did about that, a few little points about problems we encountered, why we did it, how we did it, and so forth. That is a historical survey referring back to the late ’60s and early ’70s.
2. The Nature of Order. Then, I’m going to summarize the theoretical framework which has evolved out of the pattern work: a framework which is about to be published in a series of four books collectively called The Nature of Order, four books that will be put out by Oxford University Press in the year 2000. That framework is a fairly radical departure from what the pattern language in the earlier theories contained, although it is consistent with them. [….]
[04:50] [3. What the Future Holds in Store: The Generativity Problem and the Generation of a Living World] [….]
[06:00] All of my life I’ve spent trying to learn how to produce living structure in the world. That means towns, streets, buildings, rooms, gardens, places which are themselves living or alive. My assumption here — a sad one — is that for the most part what we have been doing for ourselves, at least during the last 50 years or so, perhaps starting somewhere around World War II, has virtually no ability to produce that kind of living structure in the world. This living structure which is needed to sustain us and nurture us and which did exist to some degree in the traditional societies and in rural communities and in early urban settlements has disappeared. It is drastically gone. We don’t know how to create it or generate it any more.
[08:30] The [initial] idea that materialized in the published pattern language was first of all, of course, intended just to get a handle on some of the physical structures that make the environment nurturing for human beings. And, secondly, it was done in a way that would allow this to happen on a really large scale. And, what I mean by that is that we wanted to generate the environment indirectly, just as biological organisms are generated, indirectly, by a genetic code.
Architects themselves build a very, very small part of the world. Most of the physical world is built by just all kinds of people. It is built by developers, it is built by do-it-yourselvers in Latin America. It is built by hotel chains, by railroad companies, etc., etc.
How could one possibly get a hold of all the massive amount of construction that is taking place on Earth and, somehow, make it well, that means let it be generated in a good fashion and a living fashion?
This decision to use a genetic approach was not only because of the scale problem. It was important from the beginning, because one of the characteristics of any good environment is that every part of it is extremely highly adapted to its particularities. That local adaptation can happen successfully only if people (who are locally knowledgeable) do it for themselves.
In traditional society where lay people either built or laid out their own houses, their own streets, and so on, the adaptation was natural. It occurred successfully because it was in the hands of the people that were directly using the buildings and streets. So, with the help of the shared pattern languages which existed in traditional society, people were able to generate a complete living structure.
[10:40] In our own time, the production of environment has gone out of the hands of people who use the environment. So, one of the efforts of the pattern language was not merely to try and identify structural features which would make the environment positive or nurturing, but also to do it in a fashion which could be in everybody’s hands, so that the whole thing would effectively then generate itself.
What, now, of my evaluation of what you are doing with patterns in computer science?
[12:30] The pattern language that we began creating in the 1970s had other essential features.
First, it has a moral component.
Second, it has the aim of creating coherence, morphological coherence in the things which are made with it.
And third, it is generative: it allows people to create coherence, morally sound objects, and encourages and enables this process because of its emphasis on the coherence of the created whole.
[12:40] I don’t know whether these features of pattern language have yet been translated into your discipline.
Take the moral component, for example. In the architectural pattern language there is, at root, behind the whole thing, a constant preoccupation with the question, Under what circumstances is the environment good?
In architecture that means something. It means something important and vital that goes, ultimately, to the nature of human life. [….] The moral preoccupation with the need for a good environment, and for the living structure of built environment, and the objective nature of that question, is largely accepted. [….]
… I have no idea whether the search for something that helps human life is a formal part of what you are searching for. Or are you primarily searching for — what should I call it—good technical performance? This seems to me a very, very vital issue.
[15:10] People have asked me what kind of a process was involved in creating the architectural pattern language. One of the things we looked for was a profound impact on human life. We were able to judge patterns, and tried to judge them, according to the extent that when present in the environment we were confident that they really do make people more whole in themselves. Of course you may ask, How in the hell did you test for that? But that is too long a story which I cannot cover in this speech. The important point is that such testing was going on continuously.
[15:30] A second, almost more important thing was going on. Whenever we had a language under development we always asked ourselves, To what extent does that language generate (hence produce) entities (buildings, rooms, groups of buildings, neighborhoods, etc.) that are whole and coherent?
In other words, suppose I write a pattern language for a campus, and, I think I’ve got some sort of a language that looks as though it will actually do the job. To test it, I let it loose by giving it to people and asking them (in simulated form) to generate different campuses with this language. Let’s see what the resulting campuses look like. And we test it ourselves in the same way, by using it to generate designs, rapidly, and only for the purpose of testing the results for their coherence.
As it turns out, many of the languages that one creates do not generate coherent designs or objects. That is, they contain a bunch of good ideas. One can use these good ideas to (sort of ) put something together from them, and a few fragmentary structural ideas will be present in the result. But that does not yet mean that the campuses created (in the above example) are coherent, well-formed, campuses. We were always looking for the capacity of a pattern language to generate coherence, and that was the most vital test used, again and again, during the process of creating a language. The language was always seen as a whole. We were looking for the extent to which, as a whole, a pattern language would produce a coherent entity
[17:15] … it looks to me more as though mainly the pattern concept, for you, is an inspiring format that is a good way of exchanging fragmentary, atomic ideas about programming. Indeed, as I understand it, that part is working very well.
But these other two dimensions, (1) the moral capacity to produce a living structure and (2) the generativity of the thing, its capability of producing coherent wholes — I haven’t seen very much evidence of those two things in software pattern theory.
The Nature of Order
[18:30] The pattern theory was followed by a deeper the- ory. I began to notice, by the late ’70s, some weaknesses in our work with patterns and the pattern languages.
(1) Under the circumstances that I was most interested in, when we and others were using these patterns to generate buildings, the buildings generated were okay but not profound.
[20:10] To what extent did they really have coherent living structure as wholes?
By the late ’70s, I had begun to see many buildings that were being made in the world when the patterns were applied. I was not happy with what I saw. It seemed to me that we had fallen far short of the mark that I had intended.
But, I also realized that whatever was going wrong wasn’t going to be corrected by writing a few more patterns or making the patterns a little bit better. There seemed to be something more fundamental that was missing from the pattern language. So, I started looking for what that thing was.
(2) At about the same time I began to notice a deeper level of structure and a small number (15) of geometric properties that appeared to exist recursively in space whenever buildings had life.
These 15 properties seemed to define a more fundamental kind of stuff; similar to the patterns we had defined earlier, but more condensed, more essential—some kind of stuff that all good patterns were made of. [….] Anyway I began to notice that particular individual patterns seemed really to come always from the 15 deep properties that kept occurring again and again.
[22:35] (3) Another thing that was happening around this time (late ’70s, early ’80s), my colleagues and I began toughening up our ability to discriminate empirically between living structure and not living structure.
During the years of doing the pattern language, we’d really been intuitive about that and not very rigorous. We were just trying to get patterns written and learning to apply them without asking rigorously if they made buildings with more life in them.
But, at this point (about 1980), we felt it was pretty important to get a fix on the difference between a chair which has a more living structure and a chair that has a less living structure. And the same for a building or a room or for a main street in a town. If you want to say this one has life, this one has less life, how do you say that with any degree of empirical certainty? Can it, in fact, be made a relatively objective matter which people can agree about if they perform the same experiments?
Indeed, we did find such experimental techniques. The use of these techniques greatly sharpened our ability to distinguish what was really going on and what structures then correlated with the presence of life in a bit of the environment. The use of these techniques also helped us to refine the 15 deep geometric properties, as necessary correlates of all life in designed structures. These 15 properties turned out to be a substrate of all patterns, and began showing up more and more clearly in our work as the main correlates of living structure in places, buildings, things, space, and so forth.
[27:25] The essence of the experiments is that you take the two things you are trying to compare and ask, for each one, Is my wholeness increasing in the presence of this object? How about in the presence of this one? Is it increasing more or less?
[28:00] Then it turns out that there is quite a striking statistical agreement, 80–90%, very strong, as strong a level of agreement as one gets in any experiments in social science. All of these different experiments have to do with something like that.
Do you feel more whole? Do you feel more alive in the presence of this thing? Do you feel that this one is more of a picture of your own true self than this thing you know whatever? It is always looking at two entities of some kind and comparing them as to which one has more life.
[29:35] … to cut a long story short, it turns out that these kind of measurements do correlate with real structural features in the thing and with the presence of life in the thing measured by other methods, so that it isn’t just some sort of subjective I-groove-to-this, and I-don’t- groove-to-that, and so on. But it is a way of measuring a real deep condition in the particular things that are being compared or looked at.
[31:20] Thus there is a hint of a profound connection between the nature of matter and behavior of material systems, and the human person.
[31:55] So there began developing, in my mind, a view of structure which, at the same time that it is objective and is about the behavior of material systems in the world, is somehow at the same time coming home more and more and more, all the time, into the person. The life that is actually in the thing is correlated in some peculiar fashion with the condition of wholeness in ourselves when we are in the presence of that thing.
[33:20] … we are living in a period where perhaps the most noticeable and most problematic feature of our world is that feeling has been removed from it.
[35:50] … the 15 properties that I have mentioned provide us the ability to be precise about the nature of living structure, in just precisely such a way that it is connected, not only to all mechanical function, but also to the depths of human feeling. That is why it is an important structure.
At the root of these 15 properties, there appears to be a recursive structure based on repeated appearances of a single type of entity — the primitive element of all wholeness. These entities are what I call ‘centers.’
[36:30 spoken] In particular, just going back to these 15 properties that I mentioned, and the ability to be precise about the nature of living structure, at the root of these 15 properties, there appears to be a recursive structure with only one type of entity. This entity, in my own current writings about them, I call “centers”.
[37:30 written] All wholeness is built from centers, and centers are recursively defined in terms of other centers. Centers have life, or not, in different degree, according to the degree that the centers are built from other centers using the 15 geometric relationships which I have identified. This scheme, which is at the foundation of all the work in The Nature of Order, provides a complete and coherent picture of all living structure.
Stretching a bit, I think there may even be a little bit of a connection between the geometric centers which appear as the building blocks of all life in buildings, and the software entities that you call ‘objects.’
Centers are field-like structures that appear in some region of space. They don’t have sharp boundaries, but they are the focal organizing entities that one perceives at the
core of all pattern, all structure, and all wholeness. Everything is made of these kinds of centers. The centers are more living or less living. And, that’s essentially the only important property that they have.
And the question of whether a center is more living or less living depends recursively on the amount of livingness in the other centers that it is made of, because each living center is always (and can only be defined as) a structure of other centers. This sort of recursion is familiar in computer science. But whether the structure I have discovered and reported in The Nature of Order will translate in any interesting ways to things that you do, I don’t know.
[38:25] What is true, I can tell you from my own experiences in these last years, is that when one has this view of things in architecture, it becomes enormously easier to produce living structure in buildings. It has immediate practical usefulness. If you start understanding everything in terms of these living centers, and you recognize the recursion that makes a center, living as it is, dependent on the other centers that it is made of and the other larger centers in which it is embedded, suddenly you begin to get a view of things which almost by itself starts leading you towards the production of more successful and more living buildings.
[40:20] I can tell you in the case of buildings. If one has identified living structure with a reasonable level of objectivity, and if one has identified this recursive center-based structure as being the key to the whole thing, that’s all very well. But then of course the practical question arises, How the hell do you produce this living structure? What do you have to do to actually produce it?
You can clumsily try to find your way towards it in a particular case. But, in general, what are the rules of its production?
The answer is fascinating. It turns out that these living structures can only be produced by an unfolding wholeness. That it, there is a condition in which you have space in a certain state. You operate on it through things that I have come to call ‘structure-preserving transformations,’maintaining the whole at each step, but gradually introducing differentiations one after the other. And if these transformations are truly structure-preserving and structure-enhancing, then you will come out at the end with living structure.
Just think of an acorn becoming an oak. The end result is very different from the start point but happens in a smooth unfolding way in which each step clearly emanates from the previous one.
Very abstract, I know, but the punchline is the fol lowing. That is what happens in all the living structures we think of as nature. When you analyze carefully just what’s going on and how things are happening in the natural world, this sort of structure-preserving transformation tends to be what’s going on most of the time. That is why, when nature is left alone, most of the time living structure is produced.
However, in the approaches that we currently have to the creation of the built world and the environment (planning design, construction, and so forth), that is simply not what is happening. The process of design that we currently recognize as normal is one where the architect or somebody else is sort of moving stuff around, trying to get into some kind of good con figuration. Effectively this means searching in an almost random way in configuration space, and never homing in on the good structure.
That is why the present-day structure of cities, buildings, conventional halls, and houses are so often lifeless. The processes by which they are generated are — in principle — not life creating or life seeking. If a process doesn’t go in the structure-preserving way that I’m talking about, the result is never living structure.
In effect you can write theorems which say, Under the kind of conditions which occur in the construction industry today, you cannot produce living structure.
So, the poor folks who designed and built this convention center were stuck with something lifeless, because they were embedded in the wrong kind of process. There was nothing they could do about it. It was part of the process by which this kind of entity is produced in today’s society. As things stand, it cannot come out with a living structure at the end. That is a shattering discovery.
A very large part of my work and that of my colleagues in the last years has been one of trying to define social processes, economic processes, administrative and management processes which are of such a nature that they permit true structure-preserving unfolding to occur in society, thus to allow the generation and production of living structure.
What the Future Holds in Store: The Generativity Problem and the Generation of a Living World
[46:15] << describing where he was in spring 1996, pp 79-80 are resequenced from the talk >>
[57:10 spoken and written] Let me just go back to the structure-preserving unfolding process that I described in Part 2 of this talk. I talked about this structure-preserving unfolding process.
[written that isn’t spoken]: When I first constructed the pattern language, it was based on certain generative schemes that exist in traditional cultures. These generative schemes are sets of instructions which, carried out sequentially, will allow a person or a group of people to create a coherent artifact, beautifully and simply. The number of steps vary: there may be as few as half a dozen steps, or as many as 20 or 50. When the generative scheme is carried out, the results are always different, because the generative scheme always generates structure that starts with the existing con text, and creates things which relate directly and specifically to that context. Thus the beautiful organic variety which was commonplace in traditional society could exist because these generative schemes were used by thousands of different people, and allowed people to create houses, or rooms, or windows, unique to their circumstances.
[written that isn’t spoken]: When I first hit on the idea of creating, and using, pattern languages, I was inspired by these traditional generative schemes, and thought that I was essentially copying them. However, in the huge effort of creating a believable, new pattern language, in the 1960’s the effort went entirely onto the individual patterns (their formulation, verification, etc.), and the idea that they were to be used sequentially, one after the other, dropped into the background.
[written that isn’t spoken]: In fact, both A Pattern Language and The Timeless Way of Building say that the pattern language is to be used sequentially. In practice, however, this feature dropped out of site, and was not emphasized in use. As a result, the beautiful efficacy of traditional languages and their simple and beautiful sequential nature disappeared from view.
[written that isn’t spoken]: In our most recent work, that has changed. We are now focusing on pattern languages which are truly generative. That means, they are sequences of instructions which allow a person to make a complete, coherent building, by following the steps of the generative scheme. We have done this for houses, for public buildings, for office furniture layout, and so forth. It works. And it is powerful.
[57:10] Compared to the pattern language that you’ve seen in A Pattern Language, these generative schemes are much more like what you call code. They are generative processes which are defined by sets of instructions that produce or generate designs. They are, in fact, systems of instructions which allow unfolding to occur in space in just the way that I was talking about a minute ago (Part 2), and are therefore more capable of producing living structure. The published pattern language by comparison is static. The new generative languages are dynamic and, like software, interact with context, to allow people to generate an infinite variety of possible results—but, in this case, with a built-in guarantee of well-formed results. The design that is created or generated is guaranteed, ahead of time, to be coherent, useful, and to have living structure.
[end at 63:35]