The focus of the article is on two large-scale transformation processes that are currently taking place in the Western scientific and socio-cultural spaces. On the one hand, it is the emergence on the cultural horizon of a new macrocultural era, called Metamodern, on the other hand — the transformation in the paradigm field of Western science and the emergence of a paradigm of complexity (complexity theory). The statement is argued, that they are the different manifestations of the general large-scale socio-cultural and scientific tectonics and can serve as contours for mutual legitimacy and justification. The metamodern project captures the emergence of a new worldview in Western culture, which is characterized by a new sincerity, openness, holism in contrast to postmodern alienation, irony and sсepticism. In terms of experiencing the I-World relationship, the logic of cultural progress from Tradition to Metamodern can be described as a movement from complete immersion of the Self in the World (Tradition), through confrontation and struggle between the Self and the World (Modern), chaos of the I (multiple identity) and the World (current modernity) in the postmodern era, to a new dialectical combination of the I and the World in the Metamodern era. Complexity Theory in its sociological theoretical proposals can offer a parallel view on the process of changing cultural epochs, but through the prism of transforming the dominant mechanism of change and maintenance of social order, emphasizing the existence of two such mechanisms — organizational one and self-organizational one. The logic of changes in this dominance leads us from Tradition (self-organization), through Modern (organization), and Postmodern (chaos, no domination, the mutual distancing) to Metamodern — dialectics, tense unity of organization and self-organization. In socio-cultural terms, it looks like a dialectic of modernity (rationality, purposefulness, result, organization) and tradition (myth, game, process, self-organization), and at the level of basic experience of the world as a dialectic of acute experience of one's self combined with the experience of its unity with the world. It is at this point that the metamodern project and the paradigm of complexity in its sociological interpretation do meet. Here, they can give each other legitimizing support.

In view of the permanent crisis of the social situation in our country, the question of agents of social change acting in these crisis moments is actualized. Two variants of scientific problematization of this issue are proposed. The first is on the platform of the theoretical vision of social change, proposed by P. Sztompka, which provides a descriptive and ascertaining study of the movements, leaders, ideas and revolutions which change our society. The second option addresses the dilemma of agents and structure, which has been debated for many years in the search for a compromise between micro- and macro-deterministic models of social change. It is emphasized that the terms social transformation, transition, and crisis are not identical; namely, the crisis is characterized by unpredictable consequences of social changes. The search for theoretical micro-macro-compromise for the situation of social crisis is suggested to be searched within the paradigm combination — the paradigm of complexity, the paradigm of practices and network theory. Social changes are specified by a change in the institutional order, which is analytically divided into formal (organizational) and informal (self- organizational) constituents. Тhe difference between the manifestations of agency within these institutional constituents is emphasized. The conceptual series and outline of a possible conceptual scheme of the study of the problem are proposed.

The genesis of volunteering as a source of social agency in conditions of social tension and crisis situations shifts research attention from considering volunteering as an activity that supports the work of official structures, to considering it as a self-sufficient activity in solving urgent problems facing society in situations of social instability and institutional instability. As a research perspective, the complexity paradigm is chosen, which offers a view of social processes through the prism of nonlinear system dynamics. The basis of the conceptual framework of the study - the allocation of the two mechanisms of social change – organizational and self-organizational. The processes of social self-organization reveal themselves in the crisis moments of the life of society through the activities of powerful volunteer communities, which become agents of change due to their emergence. The characteristics of such a volunteer community are their attractiveness, procedurality and specific hierarchy, which has a leadership basis. The genesis of the community of volunteers is viewed in the context of socio-structural changes. Using the example of the interaction of volunteers with the communities of internally displaced persons and combatants, it is shown that the communities of donors and recipients are interconnected in their own development. The features of the dynamics of volunteering agency in crisis conditions are determined, which depend on the ratio of self-organizing and organizational mechanisms at different stages of crisis situations. Since the beginning of the crisis, self-organizing structures have been active independent agents, however, as the institutional component strengthens, the initiative to restore public order is gradually shifting to organizational structures and the role of agency in self-organizing structures decreases. A decrease in the energy potential of a volunteering agency is associated with internal restructuring and adaptation of communities that arose at the time of the crisis and were the main recipients of assistance. However, this potential can recover quickly against the background of new challenges (eg pandemic) and unwillingness to respond to the situation by the organizational structures.