How to explain variations in the level of donation in comparable countries? In all industrialized countries, the economic crisis of the 1980s encouraged the search for alternatives to the welfare state by encouraging third sector organizations to play a greater role in a partnership for the definition and implementation of public policies.Among Third sector organizations, philanthropic foundations provide a legal framework that allows people who wish to carry out acts of generosity by allocating a part of their personal wealth in the form of gift, for the purpose of general interest. Giving can be considered as a concrete expression of the cooperation between citizens for the common good.All democratic countries try to promote giving. The conventional explanations of the variation in level of gift among developed countries do not consider the gift as a social fact. We argue that the level of giving can't be explained by the sum of individual gifts that each respond to personal motives but by the state of the society whose cohesion is determined to both by the presence of social capital and the representation of identities.Social capital can be understood as " relationships, networks and norms that facilitate collective action." Social capital refers to relations that individuals establish them in social networks and the norms of reciprocity that arise from these relationships.This thesis is focused, first, on the level of social capital in economically developed countries and secondly on the meaning of the gift as a mode of representation of identity. It helps define social capital theory by highlighting the close relationship that unites the concept of the gift and hence the construction of identities.This analysis of the relationship between gift, identity ans social capital has direct implications for research in the field of civil society. Civil society is presented from two different perspectives. The first perspective, in a North American tradition, determines the Third sector to the sole condition of "non profit" sector. The second perspective, in an European tradition, consider social economy with organizations or enterprises within both profit and non-profit sector. These organizations and entreprises mix in their actions a plurality of economic logics.Based on the analysis of Polanyi on the embedding of the economy and its various forms of integration, associated with the Maussian logic of the gift, we try to shed light on the socio-economic dimension, or political dimension, of social economy. Social economy can be seen as a "gift economy", understood as a plural economy.Finally, the New Economic Sociology offers both an analysis of the reticular economy based on the presence and density of interpersonal ties and a cultural analysis of the economy that connects markets to values. It is possible to understand the social economy as a “social capital economy". Social capital is understood as an organizational factor and a meaning.
