the world around us and learn its structure by abstracting cause and effect,
and by documenting recurring solutions obtained under different conditions.
Such empirical rules, representing regularities of behavior, are called
"patterns." Visual patterns are the simplest expression of the pattern
concept (Salingaros, 1999). Many patterns are hard-wired into our mind:
we inherit actions and reactions that guarantee our survival. Other patterns
have to be learned, and form an artificial extension of the human mind.
The ability to observe patterns gives us the human advantage of both adapting
to, and changing our environment. Of course, the complexity enveloping
a pattern in each specific setting has to be partially cleared so as to
get at its basic mechanism.
of a group of patterns forms the groundwork for any discipline. Learned
pattern languages -- not intrinsic to the human mind -- were carefully
preserved in the past. Many patterns of human relations are codified into
religions, myths, and literary epics. A collective intelligence develops
from pooling discoveries accumulated over generations. This process is
entirely general. The sciences rely on mathematics for the ability to
organize data and explain phenomena by means of regularities, or logical
patterns (Steen, 1988). Breakthroughs occur when patterns in one area
link to patterns in other areas.
discusses the language that links patterns together. A pattern language
contains useful connective information that helps both to validate the
patterns, and to apply them. We are going to cast the structure of a pattern
language in terms of the properties of pattern combinations. Such an approach
reveals the ordering of patterns in space, time, and human dimensions.
I will assume readers have a minimal familiarity with the architectural
patterns of Christopher Alexander as published in A Pattern Language
(Alexander, Ishikawa et al., 1977). Although introduced into architecture
more than twenty years ago, their true significance has been appreciated
by only a few practitioners. Patterns are a powerful tool for controlling
complex processes, but because of misunderstandings, they have not played
a wide role in architectural design. Instead, patterns have found unexpected
success in computer science.
for this paper is anyone interested in connecting their designs to human
beings. We will show that this cannot be done without incorporating patterns.
After describing in general terms what patterns are, and the ways they
can combine, I will discuss the relationship between patterns and science.
Graph theory visually illustrates some key aspects of pattern languages:
how patterns combine to form higher-level patterns containing new information;
how linked patterns exist on different levels; how to find patterns in
a new language; and how a pattern language is validated through its connective
structure independently of each individual pattern's validity. A major
concern is how a pattern language is damaged through the imposition of
arbitrary stylistic rules and anti-patterns, which are often mistaken
for patterns. All too often, people have tried to change a society by
changing its architectural pattern language. An application to the geometry
of urban interfaces is given from the patterns approach.
is a pattern?
In A Pattern Language,
Alexander and his colleagues extracted 253 solutions or design "patterns"
that recur in architecture, such as the need for SMALL PARKING LOTS (#103),
or SIX-FOOT BALCONY -- the minimum depth that makes it useful -- (#167)
(Alexander, Ishikawa et al., 1977). They argued that built designs violating
the derived patterns were noticeably less successful than those that followed
them. The Alexandrine format fixing a pattern consists of a statement
summarizing the philosophy about a specific topic (i.e., for SMALL PARKING
LOTS): "Vast parking lots wreck the land for people."
the pattern statement by an explanation that supports the pattern: statistical
data; a scientific analysis; discovering the simultaneous occurrence of
this pattern in totally different cultures; psychological, structural,
or cultural reasons; etc. For example, the discussion following the above
pattern includes: "... the fabric of society is threatened by the mere
existence of cars, if areas for parked cars take up more than 9 or 10%
of the land in a community. ... tiny parking lots are far better for the
environment than the large ones, even when their total areas are the same.
... Large parking lots, suited for the cars, have all the wrong properties
A pattern ends
with some sort of prescription in practical terms, to help incorporate
the pattern into an actual design. For example: "Make parking lots small,
serving no more than 5 to 7 cars, each lot surrounded by garden walls,
hedges, fences, slopes, and trees, so that from outside the cars are almost
of Alexander's Pattern Language are valid to some degree -- that it reflects
the philosophy of the 1960's, that it is too radical and not easily incorporated
into contemporary design and planning, that it ignores almost all of what
is considered important architecture in the twentieth century -- but these
are trivial compared with the important message it offers. This paper
will attempt to show that any design that ignores patterns can never hope
to connect to human beings.
combine design patterns in an infinite number of ways. However, the connective
rules -- i.e., the language -- were only briefly sketched out. To obtain
an understanding of the relationship between patterns, you have to go
back to Alexander's earlier work (Alexander, 1964; Alexander, 1965). Other
than Chapter 16 of The Timeless Way of Building (Alexander, 1979),
Alexander himself has not dwelled on the synthesis between patterns. Any
perceived weakness of patterns could lie in individual patterns, but it
is more likely the result of not understanding their combinatorial language.
Although design patterns written in Alexandrine form allude to their connectivity
to other patterns (in the prelude and postscript), it is difficult to
visualize those without a connective map. Even architects who use patterns
tend to be unaware of how patterns link to each other, so the resulting
design frequently lacks large-scale coherence.
In an entirely
unanticipated development, the Pattern Language format has found a basic
application in computer programming. Any programming solution that reappears
in separate instances may be identified as a "pattern," and be subsequently
reused as a unit. Patterns are now recognized as a powerful theoretical
framework in which to assemble complex computer programs (Coplien and
Schmidt, 1995; Gabriel, 1996; Gamma, Helm et al., 1995). The proponents
of software patterns believe that patterns can help to solve a wide range
of practical problems that would otherwise be too cumbersome or time-consuming.
To give readers
a better sense of what is meant by patterns connecting to each other,
we list some examples of coupling.
- One pattern contains
or generalizes another smaller-scale pattern.
- Two patterns are
complementary and one needs the other for completeness.
- Two patterns solve
different problems that overlap and coexist on the same level.
- Two patterns solve
the same problem in alternative, equally valid ways.
- Distinct patterns
share a similar structure, thus implying a higher-level connection.
With connective rules,
two different aspects of a pattern come into play. On one hand, a pattern's
internal components will determine its inclusion into a larger pattern.
On the other hand, it is the interface that determines overlap, or connection
on the same level. Two patterns on the same level may either compete,
loosely coexist, or necessarily complement of each other.
of Alexandrine patterns arises from their clash with existing economic
practice and construction process. The Pattern Language extends from the
scale of surface detail, to the scale of a large city, and covers Alexander's
ideas on how to best implement a more human built environment (Alexander,
Ishikawa et al., 1977). Some of the urban patterns flatly contradict land
speculation and the erection of megatowers, while the building patterns
make obvious the need for more structural quality than today's contractors
are used to providing. Both of these points threaten a profit source in
the construction industry. While it is not yet clear how to reconcile
those differences, Alexander's critics find in this an excuse to dismiss
all of the Pattern Language as impractical and unrealistic (Dovey, 1990).
That is very short-sighted.
A more serious
concern comes from practitioners who attempt to apply Alexandrine patterns
to shape the built environment. The Pattern Language is not, and was never
claimed to be a design method and it is always a struggle to integrate
patterns into an actual design project. Architects, however, desperately
need a self-contained design method, and, not finding it in Alexander's
theories, will adopt whatever design method is currently in fashion. The
tools that Alexander is proposing are thereby bypassed, appearing useful
only in retrospective analysis, which also explains the Pattern Language's
relative lack of impact. Design is tremendously hard work, and I would
like to help show how to utilize patterns in practice.
A set of connected
patterns provides a framework upon which any design can be anchored. The
patterns do not determine the design. By imposing constraints, they eliminate
a large number of possibilities while still allowing an infinite number
of possible designs. The narrowing of possibilities is, after all, an
essential part of a practical design method. In this case, the remaining
choices are precisely those that connect to human beings either visually,
emotionally, functionally, or by facilitating their interactions and activities.
People have fundamental physical and emotional needs that should be satisfied
by the built environment, though most of them are neglected nowadays.
Architectural design that accommodates -- or, better still, enhances --
a framework of Alexandrine patterns will be felt as more "natural" than
one which doesn't.
The connective geometry of urban interfaces
In a living
city, boundaries define and connect different regions, and encourage many
human processes that make the city successful. Whether these functions
take place is largely a consequence of the geometry of the urban boundaries:
it has to be both crinkly and permeable. (In mathematical terms, it is
accurate to call such a line a "fractal," since it is neither continuous,
nor perfectly smooth). The needed information for this already exists
in several Alexandrine patterns, which combine to give a definite urban
geometry very different from that found in contemporary cities.
it is very cumbersome to work from a complete catalogue of discovered
patterns to create a product. A simplified connective list can drastically
improve the utility of any pattern language. A procedure for generating
such a map is based on the conceptual "chunking" of information (Miller,
1956). The goal is to cluster patterns into groups of about five or fewer
on each level of scale. Suppose one needs to design something using available
patterns; pick those that are most relevant to the problem at hand, then
choose not more than about a dozen related patterns from an existing patterns
catalogue. Identify a vertical dimension (e.g., time, space, or group
size) appropriate to the process that generates the end product, and study
how the generative process develops as one moves up the levels of scale.
Once you assemble
a group of patterns from a patterns catalogue, you can go back and develop
others for related processes, which will include patterns left out in
the initial round. Pattern groups for different results should be separate,
and not confuse each other's clarity. In the case of urban interfaces,
several patterns are directly relevant. I have listed them here, numbered
as in the Pattern Language (Alexander, Ishikawa et al., 1977).
13. SUBCULTURE BOUNDARY
42. INDUSTRIAL RIBBON
53. MAIN GATEWAYS
108. CONNECTED BUILDINGS
121. PATH SHAPE
122. BUILDING FRONTS
124. ACTIVITY POCKETS
160. BUILDING EDGE
165. OPENING TO THE
166. GALLERY SURROUND
These dozen patterns
serve as an empirical foundation for a geometry of urban interfaces.
the order of the patterns
numbered the patterns according to decreasing size, yet I will reverse
the order in the above list for our discussion. GALLERY SURROUND proposes
that people should be able to walk through a connecting zone such as a
balcony to feel connected to the outside world. OPENING TO THE STREET
is the corollary: people on a sidewalk should feel connected to functions
inside a building, made possible by direct openings. BUILDING EDGE should
be such as to encourage life, creating pedestrian nodes and the necessarily
crinkly, crenelated geometry that they require. ACTIVITY POCKETS reveal
that any public space is successful only if its edge contains and accommodates
successful pedestrian nodes. BUILDING FRONTS define the life at the built
edge of a street, while uniform set-backs "almost always destroy the value
of the open areas between the buildings." PATH SHAPE requires pedestrian
nodes along a path, and these will deform any straight edges into a more
fractal form. ARCADES connect the inside of buildings with the world outside
via an intermediate partially-enclosed space; without them, the transition
is too abrupt.
create both a boundary and a path along it, which is destroyed by having
intermediate space between the buildings. MAIN GATEWAYS give significance
-- by defining access -- to what would otherwise be a useless space between
buildings. INDUSTRIAL RIBBON functions as one possible way to create a
wide boundary for separating regions containing other types of buildings.
Finally, the two patterns NEIGHBORHOOD BOUNDARY and SUBCULTURE BOUNDARY
stress the necessity of containment in a living city, and show how one
zone can destroy an adjoining zone if the appropriate boundaries are absent.
Together, the above patterns combine to create the picture of a living
city that depends in large part on its convoluted, permeable interfaces.
The information gathered by Alexander and his colleagues in putting together
the Pattern Language offers a conception of the urban fabric as a highly
connected structure, whose subdivisions are defined by complex boundaries.
may wish to dismiss the first group of patterns as relevant only to a
pedestrian city, which in their estimation, no longer exists. Quite the
opposite is true. The discussion of this paper makes it clear that, since
human beings are anatomically geared for walking as their principal mode
of transport, these patterns are timeless and relevant even if their domain
is restricted in today's car-dominated urban landscape. They still apply
wherever we walk, whether it be in parking lots, along storefronts, suburban
sidewalks, or indoor shopping malls. Decades of suppression by patterns
for the automobile network has erased most pedestrian patterns (Newman
and Kenworthy, 1999). Whenever there is an architectural opportunity,
however, these patterns reemerge spontaneously to create a living interface.
of the patterns
presents the Pattern Language as a practical tool, and orders the patterns
in roughly decreasing size. That is the correct ordering when one is using
them for design, since decisions on the largest scale have to be made
first. Nevertheless, that presupposes that the patterns are understood
to be true in a fundamental sense. The problem is that mainstream architecture
never entirely accepted Alexandrine patterns; it was the more sensitive
and spiritual fringe movements that did. In order to validate the above
patterns, they have to be read in the opposite order: small to large.
The human mind can combine the smaller patterns into groups; the larger
patterns utilize these groupings and also generate new properties that
are not present in the component patterns. The mind is capable of validating
the patterns subconsciously when we read the patterns in an evolving (small-to-large)
Even now, more
than twenty years after its publication, the fundamental significance
of the Pattern Language is hardly appreciated. Many people still think
of it as a catalogue of personal preferences, which is a total misconception
(Dovey, 1990). Even those who realize that each pattern is established
either though empirical observation, or by scientific reasoning, often
fail to see its inevitability. I recommend, though, that you photocopy
the relevant patterns from A Pattern Language (Alexander, Ishikawa
et al., 1977), and staple them together in the reversed order. Reading
them without the distractions of all other patterns helps to connect them
in the reader's mind, and the natural progression small to large reveals
the connections between successively larger scales. Doing this leads to
the conclusion that the type of urban boundary described is not simply
our suggestion, but is necessary for a living city.
from the internal validation offered by their ability to combine, what
demonstrates the patterns' inevitability is their connection to fundamental
patterns of human behavior and movement. Many human functions and interactions
are facilitated by the proposed urban geometry, and we could graphically
link behavioral patterns to these architectural patterns directly. In
most instances, this connection is revealed as an intuition that the patterns
for urban boundaries "feel right." Alexander based much of the validation
for the Pattern Language on this intuitive assessment (Chapter 15 of The
Timeless Way of Building (Alexander, 1979)), which was dismissed as
unscientific. But a graphic and theoretical basis underlies this.
the scale on which a pattern acts, the more immediately it connects to
human beings. Architectural patterns on the human range of scales 1cm
- 1m create a visceral response because we can experience them with most
of our senses. Larger patterns that cannot be touched or felt require
synthesis and recognition; they become more intellectual. People who have
not experienced them in person (in some region of the world where they
still exist) can rarely imagine their emotional impact. This is the reason
why the sequence small-to-large works in a validation process: it brings
in the strongest personal connection at the beginning, and successive
patterns build upon an intuitively accepted base.
remainder of this paper, I will discuss patterns in very general terms,
with the intention of demonstrating their inevitability. A pattern is
a discovered solution that has been tested for some time, and under varying
conditions. For architectural and urban patterns, the time-frame can be
several millennia. A pattern is not usually invented, so creativity is
subordinated here to scientific inquiry and observation. Although you
can find novel ways to combine and relate patterns, creativity is reserved
for the products arising from an application of the pattern language,
not the process. Since patterns are derived empirically from observations,
they differ from scientific theory, which derives solutions starting from
first principles. Nevertheless, discovered patterns provide a phenomenological
foundation out of which scientific theories can grow. Once established,
those theories explain why some patterns work.
a pattern may arise as an informed conjecture. It has to survive the intense
criticism and scrutiny that are part of the scientific method of validation.
Although patterns are prescientific, they are in fact much broader than
science. A pattern may be the intersection of separate scientific mechanisms.
Many patterns do not yet have a scientific explanation; for others that
do, the explanations may be bulky and convoluted compared to the simplicity
of the pattern itself. Medicine, pharmacology, and psychology are based
at least partially on pattern languages, while their phenomenological
foundation is slowly being replaced by a biological/chemical basis. Morphological
and scaling rules that apply broadly across many different disciplines
(West and Deering, 1995) are patterns that are useful independently of
the particular mechanisms that generate the observed phenomena.
architecture as a discipline currently has no means of validating an architectural
pattern, so the basic mechanism for pattern formation doesn't exist. Architects
who are not also trained in the scientific method will not distinguish
between a design method or procedure that gives successful results and
one that fails; the validation process that should follow any proposed
solution does not form part of architectural education (Stringer, 1975).
The reasons why some buildings fail -- in the sense of being unpleasant
and difficult to use -- are never seriously examined. Consequently, design
mistakes tend to be repeated indefinitely.
reversal presents an even more serious impediment to the use of architectural
patterns. Architecture has changed in this century from being a trade
serving humanity with comfortable and useful structures, to an art that
serves primarily as a vehicle for self-expression for the architect. In
the current architectural paradigm, the emotional and physical comfort
of the user are of only minor importance. Architects resist using the
Pattern Language because they erroneously believe it hinders artistic
freedom. Declaring that they wish to express their creativity freely,
they nevertheless force themselves to work within irrelevant stylistic
constraints. Contemporary architecture has become self-referential, validated
only by how well it conforms to some currently accepted style, and not
by any objective external or scientific criteria (Stringer, 1975).
nature of a pattern language
pattern languages arise from two very different needs: (a) as a way of
understanding, and possibly controlling, a complex system; (b) as necessary
design tools with which to build something that is functionally and structurally
coherent. To visualize patterns and their interconnections, we use a graph
representation. Patterns may be identified with nodes in a graph, and
the graph is connected by edges of different lengths (Figure 1). A pattern
is an encapsulation of forces; a general solution to a problem. The "language"
combines the nodes together into an organizational framework. A loose
collection of patterns is not a system, because it lacks connections.
group to form six higher-level patterns having additional properties.
The rules by which
the patterns (nodes) connect are just as important as the patterns themselves.
Words without connection rules cannot make up a language. A coherent combination
of patterns will form a new, higher-level pattern that possesses additional
properties (Figure 2). Not only does each original pattern work in combination
as well as it did individually, but the whole contains organizational
information that is not present in any of its constituent patterns. A
higher-level pattern cannot be predicted from the lower-level patterns
alone. Sticking patterns together without proper ordering will not provide
an overall coherence. Each component might work individually, but the
whole does not work, precisely because it is not a whole.
Further connections organize the patterns in Figure 1 into a pattern
on the next higher level. New properties of the whole correspond to new
A pattern language
is more than just a patterns catalogue. Individual patterns are easier
to describe than their language, yet a catalogue is only a dictionary.
It does not give a script; it has no rules for flow, internal connections,
or ordered substructures. A patterns catalogue lacks the essential validation
that comes from recognizing the combinatorial properties in the language.
Some patterns will require other complementary patterns for completeness,
and the allowed combinations are usually infinite. A language tells you
which of them can be combined, and in what manner, in order to create
a higher-level pattern. Drawing an analogy with biological systems, the
system works because of the connections between subsystems (Passioura,
connections across scales
system has a hierarchical structure; i.e., different processes are occurring
on different scales or levels. Connections exist both on the same levels,
and across levels (Mesarovic, Macko et al., 1970). The same is true for
a pattern language. The "language" generates a connective network by which
the ordering of nodes on one level creates nodes at a higher level. This
process goes on all the way up, and all the way down in levels (Figure
3). The cohesive framework provided by the language enables the upward
transition to all the higher levels. We can better understand a language
if it has organization at different levels, because each level is shielded
from the complexity in all the other levels.
Hierarchical connections show how patterns on higher levels depend
on those on lower levels.
A pattern language
does not have a strictly modular rule structure -- as would be the case
if the language were defined by only a few basic units -- but adds new
rules as the scales grow. Higher levels in a system are dependent on all
lower levels, but not vice-versa (Passioura, 1979). Even though disconnected
lower-level patterns can work without necessarily forming a higher-level
pattern, such a system is not cohesive, because it exists on only one
level. Each level in a complex hierarchical system is supported by the
properties of the next-lower level. The combination of patterns acting
on a smaller level of scale acquires new and unexpected properties not
present in the constituent patterns, and these are expressed in a higher-level
pattern (Figure 4). Patterns on higher levels are therefore necessary
because they incorporate new information.
Patterns on one level combine to help define a new pattern on a higher
Many failures in
describing a complex system are due to not allowing for enough levels.
A gap between levels disconnects the pattern language, since the patterns
on different levels are then too far apart to be related (Figure 5). We
tend to fall into this trap because of non-hierarchical thinking. Some
urban patterns work on the scale of 100m and contain architectural patterns
that work on the scale of 1m, but what about the patterns on all the intermediate
scales? An even more serious problem is the widespread association of
importance with size in our culture. Working within that mind set, it
is very easy to concentrate only on the large-scale patterns (or anti-patterns),
and ignore those on lower levels. That makes it impossible to validate
patterns through their vertical connections, which are illustrated in
Figures 3 and 4.
Two groups of patterns are too far apart in scale to connect effectively.
One of the principal
methods of validating a pattern language is that every pattern be connected
vertically to patterns on both higher and lower levels. Damage to a pattern
language can be understood visually, by crossing out any single pattern
in Figure 3. This will remove the coordination of all the linked patterns
below it; moreover, if a vertical relation is one of inclusion, then obviously
those patterns below are also eliminated. In addition, all linked patterns
above the crossed pattern are automatically eliminated. Therefore, removing
one pattern without understanding its connections damages a significant
portion of the pattern language because it also removes at least one vertical
chain of patterns.
It is necessary
to address a misunderstanding that identifies any multi-level structure
with an inverted tree-like hierarchical ordering. In a tree, everything
is ordered from a single node above, and nodes on the same level do not
link directly. Although some authors use this terminology, that is not
what is meant here. Figure 3 shows that the hierarchy we propose for pattern
languages is not an inverted tree, because it has multiple tops and horizontal
connections; i.e., several times more connections than a tree has. A hierarchical
inverted tree structure is too restrictive, since all communication has
to pass through higher-level nodes. Inverted tree-like hierarchies are
associated with systems that exert top-down control (Alexander, 1965).
patterns for new disciplines
A new discipline
needs to abstract its patterns as they appear. It is building its own
foundation and logical skeleton, upon which future growth can be supported.
Knowing its basic patterns early on will speed up the language's development,
and guide it in the right direction. You may obtain insight into a new
field lacking a pattern language by studying patterns from established
disciplines. A universal high-level structure is inherent in all pattern
languages. The solution space, which is distinct from the parameter space,
is rarely one-dimensional, which means that knowing what doesn't work
cannot give what works simply by doing the opposite. There may be an infinity
of different opposites. One needs to exhaust the solution space by identifying
many neighboring anti-patterns before zeroing in on the pattern itself.
Here we need
to warn against the destructive tendency in our times of judging patterns
prematurely using strict criteria such as efficiency, cost reduction,
and streamlining. It is not that these are inappropriate criteria, but
rather that they tend to ignore the linkage between patterns. In other
words, patterns in a pattern language depend on each other is a complex
manner, and a hasty culling of what are erroneously deemed "superfluous"
patterns may damage the cohesion of the language. Many fundamental patterns
have been discarded in the false interest of economy, without realizing
that they are essential to a system's coherence and overall performance.
The long-term consequences of this are negative, and significant. You
may attempt to streamline a process after its complexity is well understood,
but not before. Promising new patterns, and time-honored old ones, have
been ruthlessly scrapped by short-sighted thinking, borne out of the belief
that complex systems have to conform to some sort of "minimalist design."
This comes from a superficial understanding of how a system works.
The most elegant
complex systems are nearly (but not perfectly) ordered. Having to accommodate
patterns on the smaller and intermediate scales -- indeed, actually growing
out of them -- the larger-scale patterns cannot be perfect in the sense
of being pure or too simple. Good design avoids unnecessary complication.
It is balanced between arising out of loosely organized small-scale patterns,
which could lead to somewhat random forms or processes, and patterns which
might pay too much attention to the large scale. Going too far in either
extreme damages the coherence (and therefore the efficiency) of the system.
ideas offered here prove useful in extending urban patterns to the electronic
city. The notion of an "intelligent environment" defines the urban connectivity
of the new millennium. On top of the existing path structure governed
by Alexandrine patterns (Salingaros, 1998), we need to develop rules for
electronic connectivity (Droege, 1997; Graham and Marvin, 1996). To define
a coherent, working urban fabric, the pattern language of electronic connections
(which is only now being developed) must tie in seamlessly to the language
for physical connections. Already, some authors misleadingly declare that
the city is made redundant by electronic connectivity. Such opinions ignore
new observed patterns, which correlate electronic nodes to physical nodes
in the pedestrian urban fabric. The two pattern languages will most likely
complement and reinforce each other.
two criteria: (a) internal consistency, and (b) external connectivity,
the second is by far the more important. A system's complexity -- the
extent of which may not be known for some time, if ever -- can prevent
a new pattern language from having a smooth internal structure. It is
essential, however, that any pattern language link to existing languages
at its boundaries (Figure 6). For example, a building that is internally
inconsistent would be unusable. Once a building has achieved a minimum
degree of internal consistency, however, external connectivity with other
patterns becomes more important. The point is to avoid the isolation of
pathological systems, which then survive because they are not subject
to interactive checks and balances.
The enclosed pattern candidates are internally consistent but fundamentally
flawed, because they fail to connect to external patterns.
It is possible to
define a set of anti-patterns that "clean up" complexity by imposing rigid,
one-dimensional ideas. Such a language could itself be perfectly consistent
internally, but it cannot coexist with other pattern languages that respect
complexity. The best example comes from government. Fascism and totalitarianism
clean up the messiness of human society, but clash with our most deeply-held
patterns of human values. In the same way, any organizational pattern
language that attempts to create a positive work environment will necessarily
connect with and provide a transition to Alexander's architectural pattern
language, which determines built form on all levels of scale (Alexander,
Ishikawa et al., 1977).
pattern SIX-FOOT BALCONY helps to illustrate connectivity (Alexander,
Ishikawa et al., 1977). Many social patterns of family life, such as sitting
around a table; eating a meal; children playing with toys on the floor;
growing plants in large pots; outdoor cooking on a charcoal grill; etc.,
can occur on a balcony only if it is at least six feet (2m) deep. When
a balcony is made too narrow so as to follow some arbitrary design canon
or simply to be cheap (which satisfies internally consistent criteria),
it fails to connect to the above social patterns. Connection here means
accommodation and inclusion among patterns belonging to two different
languages. Mathematical isolation, as in Figure 6, guarantees the physical
isolation of the balcony from potential users.
We don't appreciate
how completely architectural patterns connect to social patterns; the
former make up a significant part of the traditional culture in any society.
Losing them irreparably damages the way a society functions, because architectural
patterns help to define all the higher-level social patterns (Figure 7).
Especially among the rural poor, tradition is the only way of safeguarding
their culture. Tradition embodies solutions evolved over countless generations,
so design patterns are connected with and have become part of a way of
life. This point has been stressed by Alexander (Alexander, 1979), and
is very eloquently argued by Hassan Fathy (Fathy, 1973) (pp. 24-27). Sensitive
architects pay attention so that their designs accommodate and nurture
Architectural patterns that pair with social patterns (solid) further
combine to create a socio-architectural pattern on a higher level.
Sometimes, a pattern
might have an unwanted secondary characteristic; the same way an inherited
trait in an organism may be essential for survival, but have a mildly
negative side-effect. The same pattern is expressed as two different features.
Attempting to remove the secondary, unwanted feature (for example, getting
rid of every architectural element or social pattern that "spoils" an
overall perfect symmetry) without realizing what it connects to can destroy
the entire language. By condemning secondary features of human patterns
because they are not consistent with arbitrary ideas of style, or because
of some antisocial aversion, architects have succeeded in eliminating
traditional pattern languages around the world.
rules and the replication of viruses
a time of crisis, or in the desire to be totally innovative, established
disciplines sometimes willingly replace their pattern languages by stylistic
rules. Those are entirely arbitrary, however, coming either from fashion
or dogma (someone in authority pronounces a rule that is never questioned),
or they refer to a very specific situation that does not apply broadly.
Stylistic rules are incompatible with complex patterns such as the one
shown in Figure 7. The mechanism by which stylistic rules propagate bears
essential similarities to the replication of viruses. A stylistic rule
is usually given as a template, and proponents are required to replicate
it in the environment. Its success is measured not by how well it serves
any human activity, but rather by how many copies are produced.
frequently have no connection to human needs: they are just images with
a superficial symbolic content. While some are benign, many are pathological.
An information code for built form -- for example, "flat, smooth, continuous
walls at street level" -- enters the mind of a designer either through
teaching, or from seeing built examples. Otherwise intelligent people
are easily seduced by simplistic ideas in a design method, which is easy
to apply because it eliminates or suppresses natural complexity. That
individual then becomes an agent for replicating the virus. Every time
this code is replicated, it destroys human connections in that region
of the city; the result is obvious because this particular virus undoes
all the patterns for connective urban interfaces discussed previously.
a pattern is not dictated or forced, but arises out of use, and is accepted
on its benefits. It facilitates human life and interactions, and has to
continually stand up to tests of its efficacy in this respect. An essential
difference is that, because of its underlying forces, no architectural
pattern can be represented as a simple visual image. A pattern solves
a complex problem; it is not a template to be mindlessly copied. It is
far easier to reproduce a visual template than to solve a fundamental
design problem, however, because the former requires no reasoned thought;
only intuitive matching. The intellect does not need to work, and the
designer can withdraw from the responsibility of making difficult decisions
about the complex interactions between built forms and human activities.
Partly as a result of this shift, architectural design is now heavily
oriented towards visual templates defined by design style.
rules are anti-patterns: they are neither accidental, nor the simple preferences
of an individual. They intentionally do the opposite of some traditional
pattern for the sake of novelty. By masquerading as "new" patterns, they
misuse a pattern language's natural process of repair to destroy it. Patterns
work via cooperation to build up complex wholes that coexist and compete
in some dynamic balance. By contrast, stylistic rules tend to be rigid
and unaccommodating. Their replication in many cases fixes the geometry
of built form so as to exclude human patterns. Any single stylistic rule
is capable of suppressing an entire chain of linked patterns on many different
scales (Figure 3). A destructive stylistic rule, like a virus, is an informational
code that dissolves the complexity of living systems.
are trained to use a limited vocabulary of simple forms, materials, and
surfaces. Their possible combinations are insufficient to even approach
the structure of a language. This replaces an accumulated literature of
patterns corresponding to words, sentences, paragraphs, chapters, and
books that encapsulates meaning from human experience and life. Few people
realize the enormous consequences on society of adopting a particular
design vocabulary. Decisions concerning architectural style affect the
surrounding culture; contrary to what is widely proclaimed, one person's
visions are not restricted to a building as a single art work. A single
visual template can eventually destroy a culture just as effectively as
a deadly virus.
and repair of pattern languages
patterns are more-or-less permanent, yet there exists a process of repair
and replacement. Now and then, we may play Devil's Advocate and ignore
old solutions so as to see new, innovative ones in an old discipline.
A new pattern is superior if it increases the connectivity with the majority
of established patterns compared to the old pattern it is replacing. It
could have a broader context, or supersede several older patterns, thus
tightening the language. This is a process whose goal is to strengthen
an existing pattern language by repair and evolution, so as to preserve
accumulated wisdom by keeping it relevant to changing needs.
Much less frequently,
a paradigm shift occurs to make an entire pattern language irrelevant:
e.g., horse-drawn vehicles are replaced by automobiles. That does not
invalidate the pattern language showing how to create the former; it just
makes that end product less desirable. While the technology and materials
changed, however, many patterns were saved almost intact in going from
carriages to cars. In general, the adoption of innovation is greatly facilitated
by minimizing the perception of change; and consequently the number of
patterns that need to be replaced. It is wasteful to throw out a repository
of patterns, some of which may have been established over millennia.
of a new pattern language need not displace an older one entirely. Coexistence
of competing or complementary patterns is often desirable and even necessary,
especially if the new patterns occupy different positions in the hierarchy
(by acting on different scales). If properly connected, they will lead
to a richer and more stable complex system. Patterns for the automobile
transportation network were falsely believed to be threatened by patterns
for pedestrian and mass-transit networks. On the basis of this misunderstanding,
urban planners and car manufacturers simply suppressed the latter (Newman
and Kenworthy, 1999). Nowadays, we are beginning to understand that a
balanced coexistence of all three languages -- describing pedestrian,
automobile, and mass-transit movement, respectively -- is a necessary
prerequisite for a comprehensive transportation system (Salingaros, 1998).
A few patterns
might work equally well on different levels, though most patterns' context
establishes their place in a particular scale of the pattern language.
Some patterns can be moved up or down vertically within a language. Such
a property leads to economy in a pattern language through self-similar
scaling, which means that one scale looks the same as another scale when
magnified. A pattern language that develops coherence over time may also
develop a degree of self-similar scaling as a result of the connections
across levels. As the ensemble of patterns evolves a cooperative structure,
driven by the alignment of patterns (or anti-patterns) on different levels,
it creates unexpected similarities. Thus, each level of a coherent structure
expresses a property that is characteristic of the whole.
importance of detail
requires patterns on as many levels as it takes to connect to natural
processes. Every level is important by itself. In any complex system,
detail is part of the lower scales in a hierarchy. If these are unconnected,
or missing, then the system is not coherent, and cannot work (Mesarovic,
Macko et al., 1970). Neglecting a pattern because it is on a lower level
handicaps the entire structure. It is not always obvious what the lowest
level of a system is upon which all the higher levels depend. Detail that
is part of a scaling hierarchy will be connected to all higher levels
of complexity, and is not just "added on." Physical forms have structural
features on different scales as a result of internal and external forces.
From the microscopic to the macroscopic through all intermediate scales,
different levels of scale cooperate.
In the design
of buildings, there are several scales -- corresponding to the human range
of scales, 1cm to 1m -- that are difficult to justify purely on structural
grounds. Yet, in order to define a connected hierarchy of scales, those
scales have to be present in the structure (Salingaros, 2000). Therefore,
either the design should allow the emergence of structure and subdivisions
on those scales, or substructure has to be intentionally generated on
those scales. This need creates traditional "ornament" and all the patterns
that generate it (Alexander, Ishikawa et al., 1977; Salingaros, 1999).
The appropriate ornament is essential for a large form to be coherent
(Salingaros, 2000). An analysis of structural coherence arising from a
linked hierarchy of scales reveals the necessity for ornament, though
nowadays, ornament is discordant because it is unrelated to the larger
Detail is a
separate question. The smallest perceivable detail at arm's length goes
down to 0.25mm, which relates to a visual system such as a textile or
a computer display. While such detail is available in richly-textured
materials, it is usually the scales between texture and ornament (1mm
- 1cm) that are missing from contemporary buildings. Our minimalist design
tradition removes the intermediate and smaller scales from built form.
After half a century of training in this idiom, we tend to forget that
the best-loved architecture (Modernist included) works especially well
on these scales. People need to connect to structure on every scale.
languages encapsulate human experience, and help us cope with complexity
in our environment. They apply to everything from computer programs, to
buildings, to organizations, to cities. A civilization's pattern languages
are often synonymous with its technical and cultural heritage. New spheres
of human endeavor develop their own pattern language, which must link
to existing pattern languages in related fields. Individual patterns are
validated empirically over time. The language itself will be on the right
track if it evolves a connective structure that incorporates scaling and
hierarchy. Architecture and urban design in the twentieth century rely
on a set of stylistic rules that fail to connect to patterns of human
life. People have been taught by schools, critics, television, and magazines
to prefer abstract visual forms, and to ignore the fact that environments
generated by such templates cannot accommodate their own behavioral patterns.
An example of this was traced to a fundamental misunderstanding about
urban geometry. It is believed that the removal of urban interfaces would
help to create the contemporary city, but it has seriously damaged it
argued that patterns provide a necessary foundation for any design solution
to connect with human beings. Contradicting them disconnects the built
form from people. This conclusion has profound consequences for architectural
practice. It drastically shifts the position of pattern languages in contemporary
architecture. From the peripheral position at the fringes they have occupied
for more than two decades, they jump to a central point of architectural
relevance. Pattern languages were revealed as the "taproot" of all architecture,
from which design draws its life by virtue of satisfying human needs.
This is true even if one disagrees with one or more of Alexander's patterns.
Our results imply that design styles which cut themselves off from this
source of life are condemned to remain forever sterile. Those that intentionally
do so have to admit from now on that this is indeed their aim.