Transversal city and transtopia – reflecting and analyzing migration, the city, and “the urban” after the postmigrant city

“Transversal city” and transtopia are an invitation to rethink, conceptually and empirically, our urban future. Individual actors, persons with and without migration/flight background, today appear more and more transversal with respect to how they perceive the world, how they give themselves an identity, how they confront others, and how they observe, reflect, and produce knowledge. Previous “modern” static, clearly defined, and discernible constructions of belonging, which follow the “either/or” logic of socio-structural statistical ordering schemes, are actively rejected in a reflected way. Instead, belonging and identity are constructed individually following a reasoning which is transversal: spontaneously, situationally, by improvisation, oriented to potentials, crossing boundaries, transgressing, and generating abstract order and multiple references.

Observed transgressive tendencies are discussed starting from a postmigrant perspective, which is part of the recent migration discourse. By identification of four main characteristic discursive moments, transversality is conceptualized, analyzed, and differentiated from the explicitly postmigrant perspective, which is part of the critical perspective. Instead, the concept of the “transversal city” arises with its changed modes of knowledge production, its consequences for social justice and sustainable development, and the evolution of a new processuality of governance, in politics and planning, urban agendas, and the production of “the urban”.

1 After the postmigrant city

Following the intellectual figures and lines of argumentation of cultural and postcolonial studies, in recent years a critical explicitly postmigrant perspective has developed as part of the migration discourse. Like in case of the postmodern and postcolonial discourse, the postmigrant perspective should not be considered an epochal change in the sense of a “before” and “after”: it rather represents a retelling and reinterpretation of the migration phenomenon with its spatial consequences, which puts the increasing diversity of society due to migration into focus together with the encouragement to rethink the significance and connotation of migration.

In contrast to assimilating and homogenizing ideas of a majority society characterized by modern thinking, migration history is not linear but an intersecting network in its own cultural time: modern understanding of difference is questioned; new images, representation techniques, values, and concepts of subjectivity are generated. Required is a new urbanity, rethinking, and new comprehension of “the urban”. This creates contradictions which can only be resolved with new perception and interpretation patterns, leading to new forms of procedure of governance, urban agendas, and urban production processes.

My own analyses (West, 2013, 2014a, b) of this observed transition towards increasingly complex structures and dynamics in society, in conjunction with the dynamization of value orientations (West, 2017) towards transversality, point to a fundamental moment or orientation in the field of discourse about migration, which is transversal–transgressive. This moment addresses radical demands for reflection not only to academia, science, and research but also to spatial planning, design of new urban spaces, and urban governance.

Altogether four fundamental moments of the discourse on migration and integration are developed which underlie the partly contradictory integration concepts discussed in research, policy, and planning literature (Sect. 2). From the postmigrant perspective (a postmodern/modern critical one), a consistently postmodern “transversal moment” (Sect. 2.2.4) is identified, which can be associated with an individual fundamental transversal–transgressive orientation and ability and which marks a transition between different constellations of reality and forms of action. The consequences of the increasing complexity on the discursive level for the city and the urban are analyzed (Sect. 2). Starting from utopias, or the search for the ideal city, juxtaposed by the Foucauldian heterotopias, the production of the urban is theoretically developed based on the triplicity polis–city–urbs incorporating concepts of power by Spinoza and Hannah Arendt. Finally, the transversal city is conceptualized (Sect. 3), taking the increasing complexity of society into consideration and recognizing the transversal orientations of individuals as a starting point, which raises the question of how transversal orientations and transversal logics (Sects. 2.1, 2.2.4 and 4) relate to social and spatial practices (Sect. 3). However, it is important to understand that the concept of the transversal city not only serves to formulate adapted analyses and theories and decipher complexity, but also to generate, carry out, and transfer transversal urban practices (in planning, designing, governing) and to discuss the consequences for transdisciplinary–transformative urban research. Furthermore, it can be regarded as an epistemic agenda (Sects. 4 and 5).

2 Discourse on migration/integration: concepts and moments – a systematic approach

2.1 Concepts about migration and integration in an immigration society

The current migration discourse still appears multifaceted, often ambivalent, contradictory, or indecisive and therefore confusing. It oscillates between different concepts and ideas on how living together in an immigration society can work and how migrants should integrate into society. Within each concept, modern as well as postmodern underlying notions of identity and difference coexist, which allows for differentiating broader groups of concepts along the distinction modern–postmodern and for schematically locating them within the field of discourse on migration/integration/social cohesion (Fig. 1). Central to the migration discourse is the relation between “we” and “the others”, and how on this basis a social order can be established which is considered ideal.

Figure 1 Field of discourse “migration/integration” (source: Christina West, own design translated and modified after West, 2014a:111).

Although different notions of the postmodern exist in literature, there is wide agreement that postmodern thinking generally opposes any fixed ideological or cultural attributions or definitions (Lyotard, 1984; Landgraf, 1999).¹ And if we follow the idea that the modern and postmodern are not exclusive but the postmodern rather refines and further develops positions of the modern, the postmodern observer position must be the basis for critique of the traditional integration concepts with their homogenizing collective character of modern thinking. It is this critique which gives rise to perspectives like the postmigrant one which carry the postmodern axioms of plurality in one form or another. But while for the concept clusters “diversity” and “hybridity” (Figs. 1 and 2) the observed pluralization of life is focused on in a specific way, the already radically practiced postmodern ways of life, identity constructions, and orientations of people with and without migration background are added as transversal concepts. Though not paid much attention to by research, politics, and planning, those concepts, such as individual fundamental orientation and ability (West, 2017), consistently mark a transition between different forms of action and constellations of reality and are linked to the concept of transversal reason (as inspired by Welsch, 1987:295, 1995): according to Zima (2000) during modernization the individual only achieved a “negative freedom” (“freedom from” interference or collective dictation; Berlin, 1969:169 pp.²) while there is still no “positive freedom” or “freedom to” (Berlin, 1969) act as a subject and fulfill their own desires and realize individual ways of life. Instead, real autonomy of the subject requires a postmodern identity construction of the individual, which provides internal plurality (Welsch, 1995). Then, transversal reason is the reason of transition which enables the individual to cross the traditionally persisting cultural frontiers and to allow for transculturality. Ordering schemes and attributions along the closed and closing dimensions “culture”, “ethnicity”, or “nationality” are overcome because individuals can select between many possible meanings which are transversal to these dimensions. Glissant (1989:66–67) offers a slightly different meaning of the term “transversality”: identification for Glissant is linked to multiple instead of singular roots or fundaments, which as a whole seek to liberate and at the same time to provide the fundaments for liberty, beyond the dialectical traps of an asymmetric recognition. He is one of the early key figures in postcolonial literature and criticism, but he was also close to the two French philosophers Félix Guattari and Gilles Deleuze and their theory of the rhizome (Deleuze and Guattari, 1977; Original 1976). Therefore, similar meanings and understandings of the term “transversal” can be found in Guattari (1965).

Figure 2 Moments (a) and concepts (b) of the migration/integration discourse (source: Christina West, own design translated after West, 2014a:112; 114).

Generally, modern and postmodern perspectives of the individual vary not only between but also within individual concepts of the field of discourse (Fig. 1). This is especially true for the concept clusters diversity and hybridity (Fig. 2), often leading to inconsistencies within and between the concepts. Confusion is created, and the discussion, design, and implementation of sustainable urban development in the corresponding fields of science, politics, and urban planning are complicated or even prevented.

To cope with the increasing complexity of society and in order to further differentiate the field of modern and postmodern orientations, in the following the analytic level of concepts is left in search for more fundamental dimensions. To amend modern positions for a sustainable, future-oriented urban development, at this level a postmodern observer position on society which offers critique on the modern positions is also needed. Furthermore, a postmodern planning horizon is required, which in contrast to the modern modes of target definition also allows for a postmodern development of society. This leads to the two fundamental dimensions “observer position” and “planning horizon”.

2.1.1 The dimension “observer position”

While the observer of modernity assumes a “real” world which can be described, analyzed, and constructed in terms of objectively perceptible differences (first-order observation), the postmodern observer conceives any observation or analysis as a construction process in which all observation directives are socially determined and thus historically and culturally determined. For this reason, for him the observation of the observers and how they differentiate the world becomes central (second-order observation). In general, the (de-)constructivist world view is undogmatic as the postmodern observer does not refer to a truth or predefined conception of the world. Landgraf (1999:6) points out that, although this can be paralyzing for an individual political decision, it offers the possibility to question established power relations in a much more fundamental way as it is possibly based on idealistic or liberal theories. The postmodern observer perspective not only analyzes how the world is constructed, but at the same time opens a critical view with the following questions. Why is construction done this way and not differently? For which purpose or with which aim are world perspective and geographic imagination distinctions made?

With this impulse, the critical moment (Sect. 2.2.3; Figs. 1 and 2) arises in the discussion about social handling of migration, which challenges any forms of hegemonic and hierarchical othering in the name of cultural, national, ethnical, or ethical otherness and homogeneity being constitutive for the homogenizing collective moment (Sect. 2.2.1; Figs. 1 and 2).

2.1.2 The dimension “planning horizon”

While the planning horizon of modernity is teleocratic (target-oriented) and development aims at reaching concretely predefined plans, postmodern planning is nomocratic (rules-based) (Fig. 2). Using general or abstract rules, planning now concentrates on creating or modifying underlying conditions in order to allow for the emergence and utilization of spontaneous, unplanned order (West, 2017, with reference to von Hayek, 1969). The planning horizon of modernity relies on the controllability of social development, leading to a teleocratic closing of free evolution, and social development politically as well as ideologically follows a detailed self-contained and homogeneous comprehensive plan. To the contrary, the nomocratic planning horizon is devoted to the plurality of the postmodern, which radically questions excessive planning and order and which puts into focus the fact that society consists of individuals who are different with respect to their needs, wishes, experiences, orientations, and ways of living.

In postmodern planning, differences are no longer resolved or hierarchized like is characteristic for the homogenizing collective moment (Sect 2.2.1; Figs. 1 and 2) or questioned (corresponding to the critical moment, Sect. 2.2.3; Figs. 1 and 2): they are rather accepted as such or even rated as positive for development of society. The impulse of accepting that the others are equal and different can be described as a cosmopolitical moment (Sect. 2.2.2, Figs. 1 and 2). The transversal moment (Sect. 2.2.4; Figs. 1 and 2), however, is finally able to resolve those differences completely because instead of the attributes, the individual persons, which have remained widely invisible in the discourses of modernity, are the focus of postmodern observations. The cosmopolitical moment, and even in a much more fundamental way the transversal moment, raises the following question: which types of order and planning are needed in the postmodern society? Or – as a more radical view – is a transversal society, creating orders and planning modes which follow a transversal reason, appearing just because of more and more transversal–transgressive orientations?

2.2 Moments of the migration/integration discourse

The analysis of the field of discourse about migration and integration leads to four systematically distinguishable impulses or moments which result from the combination of a modern or postmodern observer position with the respective modern or postmodern planning perspective (Figs. 1 and 2). This allows for a much more differentiated view not only on different threads of the discourse or concepts but also on planning approaches and policies. The four moments will be discussed shortly in the following. A more detailed discussion can be found in West (2014a, b).

2.2.1 Homogenizing collective moment

By combination of a modern observer position with a modern planning horizon, the homogenizing collective moment (Figs. 1 and 2) of the migration and integration discourse is obtained. Here, the relation between we and the others is observed and analyzed along seemingly objective attributes, and (pragmatic) political and planning goals are also determined with respect to these differences. As the “nation” is the socialization model of modernity, differentiation is carried out via nationality, although in most cases it is empirically substituted by citizenship or migration background (leading to a methodological nationalism or essentializing culturalism). With reference to such positively verifiable and explicit differentiations which are orientated towards such homogenizing paradigms, objectively verifiable political and planning aims are formulated, like to minimize residential segregation or to optimize spatial concentration of “guest workers”, foreign nationals, migrants, or third-country nationals.

2.2.2 Cosmopolitical moment

Distinctive for the cosmopolitical moment (with reference to Beck, 2004) (Figs. 1 and 2), which combines a modern observer position with a postmodern planning horizon, is the focus on the plurality of the world. The cosmopolitical perspective makes the incorporation or inclusion of the other a key issue and postulates (cultural) diversity as a potential for any further social development. Thus, the cosmopolitical moment becomes a dominant impulse for a large part of the diversity discourse. Fundamental for a cosmopolitical orientation is the willingness and also the curiosity to engage in the encounter with the other.

Urban and regional planners are challenged by the cosmopolitical moment to ensure existing and facilitate new diversity and hybridity as a consequence of the encounter of cultures. Such abstract goals, which are merely measurable and verifiable by conventional methods, present a planning task which is unusual but typical for postmodernity: to create the framework for a (direct) confrontation between we and the others, without again falling back to a methodological nationalism or essentializing culturalism.

Corresponding with the first-order observer position, only directly discernible structures which permit the construction of belonging, typically along statistically recorded nationality, are available to (urban) planers. Therefore, critics point out the risk that the diversity concept and respective policies fall back to multiculturalism (Uitermark et al., 2005:629).

2.2.3 Critical moment

The change in perspective from the modern to the postmodern observer position enables the critical moment (Figs. 1 and 2) of the migration and integration discourse, which the cosmopolitical view cannot provide. In the focus of critique is not only the association of meaning linked with principles of differentiation like provenience, nationality, culture, or ethnicity, but also the missing representation of marginalized and peripheral groups as well as their modes of representation. From the critical postmigrant position, migration history and its spatial effects are retold and reinterpreted, thus fundamentally questioning modern difference conceptions and generating other images, representation techniques, ideas of subjectivity, and a different understanding of urbanity (Yildiz, 2013:177). Ghetto discourses (for their critique see Best and Gebhardt, 2001), which denounce residential concentration or segregation of non-German nationals in urban centers or migrant milieus conceptualized as “parallel societies of insecurity” (Schiffauer, 2008), are deconstructed and criticized.

The critical postmodern observation is irritated by the standard utopias of modernity and juxtaposes their own ideals. The demands for planning which emerge from the critical moment are urbanity and rethinking of the urban by de-marginalizing (post)migrant concepts of life, specific interests, and transnational networks and living environments. The concrete aim is to change discrimination and lack of representation, to valorize the contributions and efforts of migrants to urbanization (u.a. Pütz, 2004; Hillmann, 2011), and to de-peripheralize and emphasize the migrant perspective as migration mainstreaming, giving rise to a call for global human, women's, civil, and social rights (Hess et al., 2009) (Sect. 4).

Both modern–postmodern moments, the cosmopolitical moment and the critical moment, finally cannot overcome the differentiation principles of the modern migration concepts: the cosmopolitical moment lacks postmodern observation, which is why modern categorizing differentiations like culture, ethnicity, or nationality are still used for implementing an abstract diversity, even if complemented with further modern categories like sex, class, etc. – then called “super-diversity” (Vertovec, 2007). Conversely, the critical moment opposes discrimination of any migrant group, and doing so, as a matter of principle, cannot avoid categorizing them as such. As a consequence, both moments are not able to succeed the criticized binary, they remain tied to the dichotomy of we and the others.

2.2.4 Transversal moment

Consistently postmodern – in world view as well as in planning – is the transversal moment (Figs. 1 and 2). The observer of the transversal moment focuses on multiple integrations of the individual in the spirit of transculturality, transethnicity, transnationality, and plurilocality. For construction of the other, the migrant, and also the hybrid which emerges from the ordering of the cosmopolitical and critical moments (e.g., like “postmigrant”) (Sect. 2.2.2 and 2.2.3), the transversal view is fully insensitive.

The fundamental impulse for the transversal moment is a transversal reason (as inspired by Welsch, 1987, 1995; Sect. 2.1), which permits the individual more and more to perceive differences and make decisions across any categories and signification limits – beyond stereotyping dogmatically hardened culturalizing classifications and overcoming any simple dualistic or binary opposition.

Individual identity constructions take place transgressively based on transversal orientations, beyond national or ethnic attributions and fixation. But transversal thinking is more than transcending – transversal thinking permeates by permanently repeating transgressions of limits, borders, structuration, and categories of differentiation by active and reflected rejection of every kind of modernist “either/or” categorization following the logic of official and/or statistical orderings. Transversal orientations are paired with the process of permanent reflection and continuous seeking of new forms of communication and negotiation. Commonalities and differences now are no longer fixed along predefined inherited differentiation schemes but freely evolve under conditions of orders of knowledge which cross, overlap, and compete over and over again, arising from the use of improvisational modes (Sects. 4 and 5).

Postmodern (urban) planning (Figs. 1 and 2) is now challenged by the transversal moment not just to observe and decipher the multireferentiality and polycontexturality and thus the relationality of concepts of life from a national (or migration background) and even more from an urban and district perspective: it must also react with a new and radically changed understanding of planning and politics. Transversality does not require any presuppositions or assumptions on the structure of the world. By observation of individuals with their self-attributions, temporary assignments are constructed, which however are critically questioned again and again.

Therefore, the following questions arise: how do transversal orientations and perspectives relate to social and spatial practices and is a specific formation – a “transversal urbanism” – appearing? Transversal urbanism is then a set of interrelated processes that entangle various actors that engage transversally to official or dominant hegemonic logics – in a bold, dynamic, spirited, improvisational, co-producing way. It is important to understand that the aim of transversal urbanism is not only to formulate adapted analyses and theories, but to discuss the consequences for transdisciplinary–transformative urban research and also generate and carry out transversal urban and planning practices – creating the transversal city (Sects. 3–5).

3 The transversal city and production of the urban: utopia–heterotopia–transtopia

With the transversal city (Fig. 3b), which takes the increasing complexity of society into consideration and which recognizes the transversal orientations of individuals (Sect. 2.2.4), I develop a concept which leaves the purely discursive level behind and focuses on space and its production in several dimensions. Therefore, this concept also raises the question of how transversal orientations and transversal logics³ relate to social and spatial practices. Because obviously with the inherited paradigms and categorizations which still prevail in research, politics, and planning, we are not only ignoring the ongoing dynamics in society and the urban sphere: they are also no longer suitable to cope with increasingly complex realities.

Figure 3 Utopias–heterotopias–transtopias: the transversal city (source: Christina West, own design).

For a systematic analysis of the production of the urban with the respective underlying interaction modes and schemes of power and control in urban development processes, an earlier more general model is further developed which conceptualizes the production of the urban via the triplicity polis–city–urbs (West, 2009, 2017; Fig. 3).

Starting from utopias, or the search for the ideal city, juxtaposed by the Foucauldian heterotopias, the production of the urban is theoretically developed incorporating concepts of power by Spinoza and Arendt. By reflecting this basic model of the urban production and by incorporating transversal orientations/perspectives and transgressive practices, the transversal city is conceptualized (Sect. 4, Fig. 3b).

Utopias (from Greek non-place) (West, 2009, 2017; Fig. 3), are the non-places, they are the conceived, conceptualized, or imagined spaces which arise in people's minds. They are not real, they will never exist, and they are unrealizable and unfulfillable. Utopias are paradise-like ideas which as imagined ideas, guidelines, plans, concepts, or visions shape the future of society, always in search of a better place, an ideal city. Strictly, they describe any nonexistent society.

Following Foucault (1966/2005:9), with the intent to realize utopias, heterotopias arise as “localized utopias” (Fig. 3). Heterotopias bring together several intrinsically incompatible spaces in one place. As such they reflect existing structures and value orientations in society, and their functions are either compensation, by creation of an ordered space in a “confused” disorder, e.g., providing order in increased urban complexity, or illusion by creation of an “ideal space” as an antipole to real space, which allows for coping with the unfulfilled utopia.

At the same time, the self-conception of politics, administrations, and planning is determined by a belief in order and a fear of disorder. Therefore, politics with the help of their own political utopias and their respective planning guidelines try to discipline, structure, and order the chaos of the urban space by building the physical–material structure of the city, implementing functional areas and zoning via spatial orderings, by urban development planning and architecture carried out more and more in partnership with or by private investors, developers, and capital (PPP – public–private–partnership) (Fig. 3, triangle left side “polis–city”), while the public reacts with the emergence of heterotopias (Fig. 3, triangle baseline).

With this antagonism between political utopias (“polis” in Fig. 3) and the public (“urbs” in Fig. 3), the question about negotiation processes during the production of the urban – and therefore the question of power – is being raised using the concept of Spinoza (Delgado, 1999:193), who distinguishes between “potestas” and “potentia” (Fig. 3). Potestas is conceptualized as a (unlimited) power and control over, which means it is transitive power which needs a referent to dominate, which is restrictive and linked to institutions or persons. Conversely, potentia is conceptualized as a relationship to the whole world. With Hannah Arendt's space of appearance, potentia in Spinoza's concept of power can be further concretized: following Arendt (1960:193), potentia always manifests itself in the space of appearance when people come together and words and deeds appear inextricably linked to establish and consolidate new relations and thus create new ties and new realities.

Power corresponds to the human ability not just to act [or do something but also to align oneself with others and to act by mutual consent (text in brackets by C. West)] … to act in concert. Power is never the property of an individual; it belongs to a group and remains in existence only so long as the group keeps together (Arendt, 1970:44).

For Arendt, power is understood as a potential for power, the enabling potential of power, which unites and which is not always aim-oriented but always creative. Therefore, it can only emerge in the performative space of appearance of speech and action. While the polis (Fig. 3) can be connoted with a (hegemonial) power of organizations that controls, excludes, orders, and categorizes in familiar hierarchies or patterns of control and is linked to potestas, public space (urbs in Fig. 3) is more linked to the intransitive potentia of the space of appearance, but which starts vanishing as soon as it becomes unbalanced by dynamics of potestas, starting by an increase in the level of organization.

The concept of the triplicity polis–city–urbs (Fig. 3) can now be used as a conceptual basis for describing the production of the urban. The interaction of urbs and polis can proceed in different modes, which can be differentiated along the right side of the triangle (Fig. 3): lower positions close to urbs correspond more to Spinoza's enabling power, urban space, and the archetype of Arendt's space of appearance with its open and creative production processes and a low or loose organizational level, activating the active and productive condition of the agora (from Greek meaning central assembly place of a city, important institution). Instead, positions closer to the polis can be identified as processes accompanied by a higher or tighter level of organization order, control over somebody/control by somebody (potestas), and (hegemonial) political utopian thinking.

For Arendt, action is participation in the political life that discloses persons in their singularity, and also gives them the opportunity to be remembered – to be part of the collective memory not only of the communicative but also of the cultural memory (West, 2011).

Action is important for Arendt because through words and deeds persons can accomplish acts that are unique to them. “In acting and speaking, men show who they are, reveal actively their unique personal identities and thus make their appearance in the human world” (Arendt, 1958:179). In other words, political action discloses “who” someone is (Sect. 4).

With the above said, one could come to the conclusion that the space of appearance, at least to some extent, overlaps with the transversal moment (Sects. 1, 2.1, 2.2.4, 4). However, as Arendt points out, individuals give birth to the space of appearance by their presence and in order to hereby ensure a community: the space of appearance is a political space, bounded to the idea of the collective, which arises from a specific situation for the change which like-minded individuals seek. Where people organize, they do it for acting and gaining power. The teleocratic postmigrant logic is still engaged with the distinctive sense of community, the distinction of like-minded people, which is intrinsic to the critical moment (Figs. 1 and 2) and thus is contrary to the reason of transversality. The transversal moment (in the first place) does not know “counterprojects”.

Instead, adopting the dynamics of transversal orientation and following the logic of transversal reason which persons with or without migration background actively and purposely use against any form of attribution or definition and instead willfully claim interpenetrating transgressing practices based on transversal reason, we can ask ourselves the following question: do we prefer encountering positions or persons? Conversely, the question can be asked whether the individual contents itself with representation or wants to be visible itself. With a transversal orientation, not positions or representations but rather the individual with its differentiated logics, perspectives of the world, intentional utopias, and desires for the future is envisaged – and this has consequences.

4 Transtopia and co-production of knowledge

Transversal city (Fig. 3b) is not only a framework for research, analysis, and transfer but, perhaps even more importantly, at the same time an epistemic agenda: under which conditions is (what kind of) knowledge produced? And more precisely, who defines which knowledge gains entrance into the communicative and cultural memory? Who defines which knowledge becomes relevant for the production of the urban? Who has the right to knowledge production?

Production of knowledge is on the move now (West, 2018). Internal academic discussions on how new insights are obtained and how quality of knowledge is guaranteed transform into a discourse on the level of society as a whole. Academia is challenged to react with new modes, directly with society. Instead of researching society from the distance of an “ivory tower”, transdisciplinary co-production of knowledge comes into focus – which means co-designing research questions, co-generating knowledge, and co-creating future orientation and sustainable development with nonacademic partners on various levels like politics, administration, developers, speculators, architects, urban planners, artists, activists, refugees, inhabitants, city users, etc.

Therefore, the forms and routines how knowledge is produced need to be altered to cope with the increasing dynamics and complexity of urban life. New methods, processes, formats, and heuristics as well as political processes need to be developed. To accomplish co-production and a transformation to future-oriented urban development, I concentrate on the question of “how” for urban processes, also for procedures of organization, negotiation, and decision-making, forcing me to critically reflect the sustainability paradigms which are typically developed around the three dimensions: ecology, economy, and social. While the first two of them are quite clear and stringent with respect to their objective, the understanding of the dimension “social sustainability” is multifaceted, and a clear-cut and undisputed definition is not available and does not appear to be feasible. Most often it is constructed as facilitator of social justice. However, social sustainability de facto is rather thought of as social equity, in a more functional sense like urging equitable distribution of resources in society to provide fair access to local services, housing, labor market, and material well-being. It thus follows the idea of optimizing physical and social processes (of the city, Fig. 3) from a planner's perspective in the tradition of social engineering and repairing, which is related to specific types of organization, governance regimes with their administrations, and an understanding of power closer to the sense of potestas (Sect. 3, Fig. 3).

But at the same time, social justice today is also more and more often identified with diversity and democracy, with just participation and the question of whose voice will be heard. Who has the right to vote, and under which acts and processes of citizenship migrants and newcomers, but also others, gain their agency as urban residents? These questions focus on those rights which are not based on nationality but on the current living place. Urban citizenship is nothing one owns or holds, but needs to be accomplished and fought or negotiated for by everybody again and again. It is rather an act than a status, focusing on agency-centered processes by which subjects/residents constitute themselves as citizens regardless of status, and in which they relationally and hierarchically articulate their identities against new and old others. Hereby they question and thus destabilize established status, categories, positions, and orderings. Consequently, the familiarity of both who can be a citizen and the practices that can be understood as citizenship has to be rethought and renegotiated.

Thus, essentially two quite different manifestations or notions are merged under the generic concept of social justice, making the social dimension of sustainability appear multifaceted, contradictory, and hard to operationalize. As in past discussions on social sustainability the main focus has been on equal distribution; it makes sense to leave the notion of social justice as social equity rooted in the social, i.e., the third dimension of sustainability.

Conceptualizing equality, agency, and recognition as act or process rather than status enables us to rethink sustainability as not fixed: it has to be thought of as dynamic and always negotiated (in everyday life). This leads me to postulate the fourth dimension of sustainable development, the “cultural sustainability”, which refers to the way negotiation is carried out. Culture here is understood as the process and thus the mode of negotiating meanings, which – especially in connection with sustainable, future-oriented (urban) development – is linked to transdisciplinary co-designing of relevant research questions in society as well as the co-production of knowledge.

However, in the moment when we start to rethink the relationship between participation in society, rights, and recognition, we also have to ask how participatory structures and political agency constitute each other in interwoven dynamics. Therefore, we also need new political formats and political processes of implementation, which need to be adapted to continuously changing co-production modes and negotiation processes. They are likewise fundamental for reaching future-oriented, sustainable (urban) development, which leads me to consider them as the fifth dimension, the political dimension of sustainability and sustainable development.

In summary, to focus on the concept of the transversal city means to de-center urban theory, by offering and creating bold, dynamic, spirited characterizations of modes of production of the urban and urban space different from those generated under the dualistic opposition of either/or or by a binary structuration in any we and the others tradition (Sect. 2). Bringing robust knowledge to urban research and urban transformation produced from a transversal perspective, new archives will be generated by taking the idea of “thinking with an accent” (Braidotti, 2014) seriously.

Transversal orientations are being set in motion – modifying normative paradigms and mainstreaming while they transversally engage with (and not necessarily outside) official logics as a matter of negotiation and transformation. Experiments in politics and democracy generate new modes of politics through practices that produce new kinds of urban citizens and citizenship, social and political agency, claims, and contestations.

Experimental spaces and spaces of opportunity, which are not formally predetermined, can serve as catalysts for transversal thinking and acting, co-designing of research questions, and co-production of knowledge. They are needed to enhance transversality and to train individuals and society in experiments in democracy and politics. Whenever no single pattern of thinking is dominant, improvisative open-end processes can be learned. By improvisation and subsequent reflection, the repertoire can be augmented, and urban development processes stay constantly in motion. Transversal orientations are processual and transactional by means of improvisation. Improvisation is the reflective, situational, and intentional transgression of a plan (Dell  2007:137) – not to gloss over but to recognize the flexibility of transtopia (Fig. 3b).⁴

Transtopia is the space of improvisation, experimentation, and co-production which ensures evolution and innovation by transgression, where the urban is conceived and conceptualized from the future of society and the urban sphere is kept in motion, where democracy and new modes of politics are experimented on, and where – in contrast to the space of appearance (Sect. 3; Fig. 3) – the physical–material structure of the city is co-designed.

Consequently, in the transversal city the inextricably linked antagonism of utopias and heterotopias finds itself augmented by the entity of transtopia, which is the transversal mode of experimentation and co-production and which embraces urbanity and its production as a whole (Fig. 3). However, that does not mean that – in the same sense that modernity always remains contained in postmodernity or migration remains in postmigration – modern modes of observation or planning and thus also utopias and the correspondingly evolving heterotopias will not somehow remain part of the repertoire of the transtopia (Fig. 3b).

The new modes seem threatening – there is scarcely certainty. Knowledge stocks and archives as well as self-perceptions are challenged.

5 Conclusion and outlook: implementing transtopia

In implementing transtopias, the challenge of the migration and integration discourse is thus to continue thinking about an optimistic narrative of our future society and living together and explore the question of which knowledge is actually still missing. Addressed here is not only “expert knowledge”, but also a transdisciplinary–transformative knowledge: a knowledge which not just complements or rounds off scientific and nonscientific or practice-related knowledge by transcending disciplines, but moreover generates new knowledge in new and different processes with the aim to find out what matters to people, what they dream about, what they fear, and how they want to live. To initiate these processes, in the real-world laboratory⁵ “Asylum Seekers in the Rhine–Neckar Region (Germany)” we designed and developed methods and formats for transdisciplinary–transformative research in the so-called “UrbanUtopiaLABs – Experimenting Utopia: Past … Present … Future. How do we want to live together in future?” (in short UrbanUtopiaLAB) (West and Kück, 2019). Here, co-design and co-production of knowledge and processes are envisaged and refugees and asylum seekers and non-refugees and non-asylum seekers create spaces of opportunity for rethinking the urban, city, and society from a future perspective.

Co-producing knowledge was both a central question and focus of the real-world laboratory “Urban Office – Sustainable Urban Development in the Knowledge Society”⁶. Beneath the four defined main projects carried out between different actor constellations, novel transdisciplinary–transformative research and teaching formats like “Wissen to Go” (West, 2018) have been developed, which are based on reflection, improvisation, and urban interventions and which help teach and disseminate transversal practices. Knowledge production, learning, and also teaching are now understood as active, self-controlled, situational, communicative processes, thus giving rise to a new transversal learning culture.

Based on the experiences in and with the different transdisciplinary–transformative movements, transdisciplinary spaces of opportunities have evolved like those which currently manifest as transtopias on the open platform “Urban Innovation – Stadt neu denken! e.V.” based in the “Urban Innovation Center Heidelberg”. Here, new processes – and thus also new formats of urban development – are not produced but co-produced among all those interested, regardless of whether they come from research, academia, economy, politics, or administration, or whether they are interested citizens. This leads to new political processes, enhancing the cultural and political dimensions of a future-oriented transformation of the urban: the fourth and fifth dimensions of sustainability and sustainable development (Sect. 4). Formats, methods, and questions are not predefined but negotiated and co-designed among all. Knowledge production is no longer hegemonic but co-produced, and transversal practices are learned through practices.

Co-producing knowledge? This is a radical but indispensable demand for radical rethinking, communicating, co-creating, and co-designing the urban, i.e., the processes which shape the lives of people in the (built) city with its utopias.