Based on the critical reconstruction of the diagnosis of modernity by A. Giddens, the article traces the logic of the transition from the institutional to the civilizational approach in the sociological discourse of “modernity”. The analysis focuses on the problem of the relationship between culture and reflexivity. In Giddens’ theory of radical modernity, reflexivity is opposed to culture, which is identified with tradition. According to the theory of multiple modernities that are genetically related to the sociological paradigm of civilizational analysis, tradition and reflexivity are correlated as two aspects of culture characterized by aspirations, on the one hand, to the reproduction of interpretive foundations that set a general context of meaning, and, on the other, to trans-contextual breakthroughs that open up new horizons of meaning. Both tendencies are in irreparable tension between themselves and are mediated in the capacity of culture to rationalization, during which the self-articulation of culture turns into its self-problematization. The combination of rationality with reflexivity leads to cultural innovation and interpretative shifts and, at least, potentially to new cultural crystallizations, allowing higher levels of self-problematization (J. P. Arnason). In different cultural and historical patterns, the ability to rationalize receives an uneven and specific development. Modernity is a “distinct civilization” (S. N. Eisenstadt), in which the tendencies of culture towards self-articulation in conflicting directions and towards self-problematization reach a level unprecedented in human history, giving rise to multiple configurations of social life intertwined with relatively autonomous dynamics of power and wealth. Although Giddens did not make a “civilizational turn” in his work, his institutional analysis of modernity closed with his formulating the problem of conjugation of culture and power, which is key for the civilizational approach in sociology. However, the same problematic also marked the limit of understanding modernity in Giddens’ theory; he recognized the incomprehensibility of the social world in which reflexivity was institutionalized. His further path was a one of utopian modeling and political implementation of the future post-modern world, rather than a one of scientific analysis of modernity.