This book attempts to rethink the rationality that developed in the west. The West has its origins in ancient Greece, Rome, and Christianity, but it is guided by ideas propagated and pursued by the Enlightenment. These ideas replaced or enriched traditional religion with belief in the value of the individual and her rational powers and inalienable rights, and with trust in science and technology, production, and trade. Openness to these ideas constitutes modernity, with which the West can be identified. It constitutes a specific rationality, a way of justifying and explaining actions, that is oriented to utility, happiness, and individuality. The West can be defined neither geographically nor historically but only by its ideas and its superior rationality. This at least is the self-understanding of the West.

In a formal sense, there can be only one rationality. In this sense rationality is a way of thinking that follows the rules of logic. Though different logics have been developed, they are different interpretations of logical thinking rather than different rationalities. All civilizations have standards of how to judge, and hence possibly change, their habits and traditions. Such standards allow for detecting logical inconsistencies in one's intentions. Yet they may also allow for detection of what Max Weber called value rationality. There are as many value rationalities as there are ultimate values by which practical rightness of thought and action are judged, not logical truth.