Concerning architecture, it is impossible to approach informality without previously discussing about form. Similar to all technical practices architecture has inherent the problem of the "end" which in the particular case is to be found in the notion of "form" not only as a mere material artifact or as "shape". This is why, no matter that I consider the form as the consequence of establishing a relationship between human beings (Behne), the way I would choose to talk about it in this first part is the one which regards it as a distinct casting, a mould. The form is not something independent from the formal; form is the precondition for the formal. It is the medium for establishing a communicating a convention, therefore establishing and signifying the formal, teaching what formal is and certainly this is not something a-spatial.
Architecture is mainly about form. It is enough to remember the famous quotes that historically attempted to influence architectural practice, "Form follows function", "Form follows this", "Form follows that" and no matter words change from time to time, the term form persists, always remains there and attempts to establish new associations with other terms in order to find definitions for what form is, or what could be. It's not a problem but it is certainly a fact that architectural practice has a tendency to aim towards the form (material and immaterial), meaning towards both formality and formalism, formality concerns both the design practice and the practices that take place in the building and formalism the output of the design, the form. This is because in the practice of architecture form is the end, and in the same time is also the aim from the very beginning.
Formal tools - Formalism
This is something that becomes obvious once we look at the architectural representations and their tools that not only are always representing the space (the building) as a material form (a material artifact) but additionally they use the form itself as a tool, or better, as a language, for the constitution of the representation itself, therefore for the production of space. No matter that architects often claim that architecture is about function (functions are also forms but this is to be described later on), their processes don't represent functions; they rather use symbols (symbols are also forms, formal conventions) in order to represent spatial forms that intend to serve functions but not the function straightforward. Form is the aim, the starting point and the conclusion.
Once something becomes formed it has concluded, it has reached its end and becomes a closed entity. Of course the how much closed it is depends largely on the particular form and the way it has been designed and materialized. In general though, no matter the degree of openness, it cannot negotiate easily with new external ends, because the largest part of its inventory of characteristics has already been set, defined, formed and even the exterior connections with other forms are preset. Often, the future or the multiple possible futures are predefined (in the case of the metabolists).
But form is only an imposed technical end; it is not the actual end. Once the form is being materialized, there comes the occupation, the living, the experience of the built space and all of them introduce new ends that often the forms have failed to predict and cannot accommodate or transform themselves in order to accept them.
In this direction, there seems to be a paradox in the architectural practice and the tools we use. When we design we think of spatial relations and we represent them as forms, but afterwards, when we build them, these forms tend to seek for new relations, spatial, social etc. that we haven't thought of, we haven't predicted and we haven't designed. Therefore, the form becomes an in between stage, a field for projection, an empty token between the creator (author) and the user. Actually, form is really an empty token; it's not the carrier of inherent characteristics that are non-spatial (meaning dimensional) and certainly does not carry an essence that refers to things that presuppose interaction, like function, that is universally recognizable or acceptable. It may convey an idea about a function but this doesn't mean that the user will perceive it or accept it. To express it better, form is a space for active negotiation between the will of the designer and the needs of the user, among different ends. But how can it function effectively as a field for negotiation when it is already formed? Shouldn't it take place before the form is born? What happens then is that informality emerges when and where it is possible, usually in the in between space (here the word space is both literal and metaphorical) attempting to cover the needs that the formal processes failed to predict, to negotiate.
Formative
On the other hand, considering the fact that the tools and methods we use for representing are scopes that are formative for our creations it becomes obvious that they have a major impact to our practices. The way we think, we design, we perceive and we practice, the ways how we see, understand and constitute things are formed, or at least influenced, by the tools we use. Obviously form is something excessively privileged in the architectural practices. It is both, architecture's aim and also the tool it uses to put space and the practices that take place into it "into order" and this is not always something innocent; Not only our tools but also what we create with them, the forms themselves, are in turn also formative. As Plato says "even the walls, the fortification, of the city educate me" indicating with these words the fact that forms are formative and they have the power to formalize.
The fact that buildings are more than passive containers of people and activities but are formative as much as the practices that constitute them[1], brings back the question we live and build or we build and live?[2]. The answer should be "we rather do both" in order to indicate that there is a constant cumulative feedback between the experience of living and the practice of building, the formal and the informal, the technical and the natural, the utopia and ethos. But what happens today tends to be the opposite, there seems to be a polarization of the dipoles described above that detaches the formal from the informal (etc) and this kind of feedback that one would expect to take place is stopped by thick borders that have been set between those terms and following they are being set in reality, in space. In the formal world and practices (including architecture) formal is strictly formal and informal is strictly informal, there is no in between space, there is no negotiation between these two, it's either the one or the other (there's no bridge that we call x-formal). This is obvious also in the how formality relates itself with the informal; it either attempts to formalize the informal, in order to control it and use it productively or isolates and excludes it in order to make it extinct no matter that the second never really works. This is the result of the fact that formal is mistakenly being considered as a closed system that has the capacity to find ends within itself and be complete as a closed entity while what is needed is rather a constant dialogue between the formal and the informal, a symbiosis.
Concerning the production of space in particular, the impact of this polarization is that in general architectural practice is preoccupied by prefabricated (or archetypical if you prefer), fixed and non negotiable ideas of what formal is (a prefabricated archetype) that are imposed over space. Through spatial forms architecture signifies and often even defines and establishes what formal is by drawing the borders between the formal and the informal. Once the formal is defined it also becomes formative. This is why architecture has often been used as a vehicle for the establishment of formality. Panopticism, invented by Bentham and analyzed by Foucault, is a good example and certainly not the only one that shows how architecture can function not only as a signifier of a power or an authority but also as a device for social construction. Together with the spatial forms we form the perception of people about what a form is (by defining what is formal), what is their "social role" what is "right" or "wrong" etc. The arrangement of the bodies in space, the various visible and invisible points, the asymmetries of visibility and in general the constitution of space assigns social roles and forms identities. We form people's act of living by applying our formal technical productions on their natural needs and instincts, by imposing artificial ends while there should be emergence of individuality being expressed in ways that not only constitute space but they also transform it to place.
This formalization of space brings, either on purpose or as a side-effect, an excessive control in spatial practices of any kind. It has as a main side effect the growing feeling of insecurity where individuals don't learn how to trust each other, to interact, communicate and negotiate. It seems that we have misunderstood and we take autonomy as isolation and detachment because we are afraid of the other. In reality it should be about interaction and negotiation and about otherness. This is the side effect of the control that isolates informality and finally excludes it instead of using it productively. It is the result of the fact that we give in more and more to a kind of communication which based in the use of closed forms and according to forms, in a binary way. Architecture itself is a form of communication and the question is, not only in what extend we are allowed to participate in the production of new forms, but in what extend we are prepared and willing to trust the participation of others.
[1] Thomas Marcus, Buildings of power
[2] Martin Heidegger, Building Dwelling living