This HDR thesis presents itself as a commitment to follow experiences and experiments on the edges of the social. The term commitment first refers to the political scope of sociological practice. It is a question of claiming the inclusion in a policy of knowledge which, first, is built by being taken and resuming the questions and investigations carried out by «ordinary» actors. Second, consider that the production of knowledge is at the same time an action in the world and that it can have effects. Thirdly, research practice is itself an ordinary practice, taken in a daily life and contingencies that must be restored. Following is part of the logic of the ignorant master (Rancière): it is not a question of leading from a point that would be the "knowledge" and guiding the ignorant (student or layman) towards this point, but rather supposes to take together the same path towards knowledge by mobilizing the knowledge of each. Experiences and experiments refer to how Dewey defines them in close articulation to each other. Experience in this context refers not simply to having an experience, to living something in the ordinary continuity of life, but to «making an experience» that is, to grasp experience as the starting point of an investigation to extract meanings for the future. In this sense, it is about emphasizing the active and transformative dimension of experience. Thus experience is profoundly experimental in that it allows us to reshape our way of experiencing and understanding the world. Experimentation then becomes the means to jointly train and transform individuals and the world. The pedagogical and democratic conception of experimentation and investigation advocated by Dewey and his contemporary proofreaders corresponds to the approaches I have developed. I wanted in this work not to dissociate the research activities and the associated environments: the fields and questions that I have invested in my research have led me to develop projects and pedagogical approaches that have allowed me in turn to open new fields and problems with various partners to whom I have associated students and alumni students. Four network diagrams reflect my attachments. As for the edges of the social: The edge of politics is for Rancière the place where emerges what is not counted by politics. It is the rest, where improper identities are manifested and processes of political subjectivation take place. The policy whose edges I explore is that of the social question: inequalities and the fight against them. I enter through actors who are not always social workers in title and by issues that are at the borders and where the meaning of social intervention is redefined (Lechaux, 2022): Local development agents to integration, the fight against discrimination, community action; or spaces where social work is done in other forms (artistic practices, health, participation of inhabitants, social and solidarity economy). I try to understand how these practices try to make other voices heard and reconfigure the sharing of places. The first volume, entitled Cheminements, grands voies et chemins de traverses (Tracks, main tracks and sleeper roads), presents and revisits the research experiments and other associated activities conducted since the thesis. The sequence of the six chapters of Volume 1 is chronological, constituting a kind of reflexive activity report: are presented the circumstances that led me to work on each question, the forms of research developed, engaged collaborations and finally some of the essential analyses produced, detailing rather what has not or little been published. The modalities of writing engaged in the various researches are the subject of a complementary analysis presented in three stages «Investigate and Write together». The first part, «initiate plural forms of cooperation and intervention» is interested in the accompaniment of a device of local development agent to the integration and shows how it allowed to develop forms of recognition (Honneth). It reports on the reflections initiated with European colleagues on the «enforceable» nature of research. The more educational projects developed around community action are presented by identifying inter-cultural and empowerment issues that arise. The second part «Knowledge policy: engagement in collaborative research-actions» details two collaborative research-actions (on the participation of beneficiaries in the RSA system and on the patrimonialization of intercultural practices) by examining in particular the tests of mutuality and truthfulness encountered in these collaborations (Callon, Audoux, Gillet). Finally, it presents the comparative research conducted on local social policies, and in particular the survey I conducted with professionals working in child protection. It thus explores the translation of the demand and the recourse to the law in this field and questions the way in which the sociologist’s survey is reacquired of the data already produced for the action. The different forms of investigation that I have conducted lie between anthropological approaches in which the experience of the encounter with the Other is central and produces effects (of knowledge and interconnaissance) and social investigations that have a more operational purpose. Zask identifies how the social survey constitutes for Dewey an inter-objectivation, referring precisely to the way it operates in anthropology: “A survey does not record in a neutral and detached way the real, nor does it unfold in the nostalgia of not being able to do so; it creates reality, social reality, new situations, social relations are replayed, at least in part” (2004, p. 10). The review of the work carried out since my thesis is thus a perspective of the investigation as an activity experimented with others according to a principle of reciprocity. I am involved in particularly rich problematization sites where actors experiment with new ways of intervening in the social. Research plays an interlocutory role to explain what is at work and jointly contribute to making it happen. Experimental research (Pascal Nicolas-Le-Strat) works at the crossroads of knowledge and experience involved in the situation. Joint experimentation thus establishes a democratic space for expression and elaboration of common questions. The democratic scope of these forms of investigation and experimentation is not, of course, due only to their methods of implementation but also to what they intend to take in common (the recognition of minorities, access to rights, the power to act and create). According to Esposito, the community is a burden shared by those affected. In contrast to a sociology that should be wary of «common sense», it is therefore a question of making a sociology that takes its part in the development of a policy of the common in a context of crises that calls to contribute to a better bifurcation of the trajectory of humanity (Dardot, Laval). The rereading of my work in the first volume, entitled Tracks, main tracks and sleeper roads, shows how I am gradually moving towards a form of sociology that claims, through research, to experiment at the edges of the social. The second volume, Passerelles, cordes et ancrages (Walkways, ropes and anchors), continues this reflection on a more epistemological level: methodological, theoretical and also political. This second volume is thus envisaged as a gateway, that is to say a means of going from the experiences I have made to those I propose to continue to develop for myself and with and for others; from the experiences already conducted, (Research and evaluation of the Experimentation Territory Zero unemployed of Long Term). In a first part, two «shared survey approaches» with students and professionals are examined: Exploring networks and Thinking by case. In the second part, «Experimentations, social innovation and participation», perspectives of comparative analysis are proposed around the forms and stakes of participation. The final chapter examines how to develop gaps between research and training, intervention and social inquiry, the academic universe and other worlds. Network analysis and case studies are examined both as approaches developed by the sociologist and as approaches found in social intervention. These two approaches are also ways of reporting: through storytelling and mapping. The case and the network are also related, in that the case study leads to explore the networks. I thus show how there is in the passage and articulation of the case to the network something of the order of the «rise in generality» but this one does not operate as much vertically as horizontally. The relationship between local site and global environment is not postulated as a determination of the second on the first, it is explained in the survey (Costey, Gardella). I propose to speak instead of an extension in intelligibility. The reflection on the operations of thinking by case is conducted from the comparison of two cases: one from my thesis on Turkish migration, the other from the survey carried out in child protection. The case, and in particular the problematic case (Passeron, Revel) or outlier case (Ragin, Becker) makes it possible to think about situations that go beyond the available categories and resist pre-existing solutions and frameworks for action and analysis. What the case is a case is first of all an enigma and this one imposes to enter into a narrative of the case. The cases therefore appear as deadlines that necessarily open to ethical and political questions (Boarini, Hennion, Vidal-Naquet). The exploration of networks (Hannerz), but also of the way they are built and represented by the actors themselves, is made from the field realized at Teil in Ardèche as part of the experimentation Territory Zero Long-term Unemployed. It is a question of paying attention to the part that each one takes in the action, to the possibilities of recompositions of roles and places, and more particularly to consider what the attachments make do (Latour). The radical and innovative nature of this experiment, which is part of a principle of (employment) law, is primarily due to the way in which the very conventions of employment and integration are redefined by this actor-network. The examination of the forms of mobilization at work, from the assembly of the project to the creation of activities, shows how capacities to act together develop to make work a common one. In the next part, chapter 3, this field is re-examined from the angle of the questions posed by participation. The TZCLD experiment is put into perspective with several of the previous research fields (RSA, Community Action, City Policy, child protection, intercultural practices). The objective is to identify what makes the possibility of doing otherwise in more or less wide or small spaces and with a more or less large transformative scope. The interest of this comparison lies in the fact that participation takes place, in the various fields concerned, in various forms and regimes, not reducible to instances strictly stamped as such. The originality of my approach lies in the fact of considering here the interweaving between the logics of experimentation, the aim of social innovation and the forms of participation in the work. This leads to questions about which environments are associated with more inclusive life forms. I thus develop a more theoretical framework of analysis that can be used and discussed by and with others. The approach of participation developed by Joëlle Zask, is mobilized to study the tensions and interweaving between participating in instituted experiments and taking part in instituting experiments. Different thresholds of participation allow or not to articulate participation (characterized by conviviality) and benefit, especially in terms of effective recognition of fundamental human rights. The way in which the contributions of each are required, solicited or established by a form of solicitude allows or not the recognition of the person as such. I propose then to distinguish the forms of participation «assigning» from «reciprocal» or «solidary» forms. When participation is developed by highly institutionalized organizations, the forms of experimentation are framed by their aims and objectives, according to an asymmetrical report. The voluntary dimension is certainly present, but the participants are identified upstream by their category of belonging: they are copies of a collection, a collective in the restrictive sense that Zask proposes. What they participate in and what they participate in does not belong to them. It is in this sense that we can speak of an injunction to participate, or even a subpoena: individuals are summoned to participate by a body exercising political power over them in which they remain caught. The construction of participation with actors outside the institution, such as ATD-quart Monde or MRIE, or with people who came out of the dependence in which they were vis-à-vis the institution (ADEPAP, Collectif Vivre Ensemble à Montreynaud) can help loosen this institutional hold. The collectives thus gathered can develop a kind of effective participatory enclave within the institution but sometimes also form more autonomous audiences elsewhere to make their voice heard in other public spaces. However, they risk having little effect on the functioning of the institutions themselves and receiving only symbolic recognition, even if this is already a step in itself. Similarly, community and associative spaces that have as their mode of operation even a principle of participation remain limited in their ability to bring transformations within institutions and more widely in society, remaining niches in the ecological sense of the term. On the other hand, they allow those who take part to define and appropriate the issues discussed, to develop capacities for action and positive social experiences as well as to allow themselves to claim their rights. In this way, they constitute essential spaces for experiencing a democratic experience that is both protective and supportive and culturally enriching. The type of participation that I have called reciprocity articulates these conditions that create individuals and groups with broader institutional and political recognition. The status acquired here by people is a benefit that is common and allows to institute a common at several scales. These reflections, and the experiment Territories Zero long-term unemployed in particular, then lead to call for the model of inclusion in which social policies would be gradually inscribed since the 90s following the models tutelary and restorative (Lafore, 2020). In the implementation of this new repository I identify two versions: one more focused on the individual that I qualify as «weak» and the other more oriented on the environment that I qualify as «strong» or «radical». The first would be social work (including some of its renewed forms of intervention), the second would be social work, claiming to reconfigure it from the edges, redistributing shares. Just as the objects I have been interested in are located on the edges of the social, in frontier spaces where the (social) work is redefined, my activity operates a work of borders (Lechaux, 2022). The last chapter of the HDR thesis examines the possible forms of hybridization between research and action but also training. It questions the way in which linked ecologies (Abbott) are created in the gaps between functions and roles more listed and instituted. Two attempts to build spaces for dialogue are examined (a colloquium project and the implementation of a practitioner-researcher seminar) which, by the difficulties encountered, reveal that it is not so simple to build bridges and cross borders; This leads to the identification of some possible hybridization tracks and figures. I then identify the possible lines of passage between research, action and training, as so many folds that give holds to make together (Bessy, Chateauraynaud). From there, I elaborate a topographical analysis of the interstices in which dynamics of cooperation can develop: when the investigation becomes a form of action, when experience leads to research and where experimentation builds jointly «knowledge» and «do». These three forms of hybridization, not exclusive to other articulations and transactions, have the horizon of building shared knowledge, establishing capabilities, recognizing people and promoting social transformations. I finally describe concretely, and in accordance with my interest in singularities and the pragmatic purpose of this thesis, these folding operations and the cooperative dynamics they make possible from the activities developed within the small SSE and social innovation cluster precisely created to cross borders. Not to finish, I invite you to consider social facts, not as objects of research but as things of research, uncertain and fragile, which require attention in order to preserve what you care about (Denis, Pontille).