Abstract
According to Husserl, the mathematization of the lifeworld involves reducing it, as object of knowledge, to what is measurable, as well as excluding other forms of knowledge of it. This has important implications in relation to the modern conception of rationality, and, significantly, of practical rationality. More precisely, it issues in an impoverishment of the notion of reason. This article examines the idea that the process of commodification associated with the consolidation and expansion of capitalism has motivated another aspect of the mathematization of nature to which Husserl alludes: the mathematization of value. Born from capitalist economy and from practical attitudes, this mathematization of value is a tendency to reduce all value to use value. In such context, this article offers a phenomenological reflection on the crisis of modern rationality, especially in relation to the difficulty to undertake collective actions that follow logics that are different from that of the accumulation of capital, based on the examination of this other aspect of the mathematization of the lifeworld.