Abstract

The peculiar legacy of Husserl’s mereology, chiefly studied by analytic philosophers interested in ontology, has led to a partial understanding of the III. LU, which is too often reduced to a chapter of “formal ontology”. Yet, the power of this Investigation goes far beyond: it enabled Husserl to deal, in the framework of a unified theory, with a vast range of particular problems. The paper focuses on one of these issues, namely abstraction, so as to expose how Husserl instrumentalizes his formal tools in order to tackle material issues. The existence of an up and down pattern is uncovered: Husserl first reinterprets the psychological problem of abstraction in ontological terms, before coming back to the original problem with new insights. The second, correlative aim of the paper is to emphasize the key role played by Friedrich Schumann, a forgotten yet crucial character for Husserl’s conception of abstraction.