The study is focused on the relation between theology and mathematics in the situation of increasing secularization. My main concern in the second part of this paper is the early-twentieth-century foundational crisis of mathematics. The hypothesis that pure mathematics partially fulfilled the functions of theology at that time is tested on the views of the leading figures of the three main foundationalist programs: Russell, Hilbert and Brouwer.

The professional mathematician is a Platonist with regard to the existence of mathematical entities, but, if pressed to tell what kind of existence they have, he hides behind a formalist approach. In order to take both attitudes into account in a possibly serious way, the concept of suprasubjective existence is proposed. It involves intersubjective existence, plus a stress on objectivity devoid of actual objects. The idea is illustrated, following William Byers, by the phenomenon of the rainbow: it is not an (...) object but can be said to possess a subjective objectivity. (shrink)