The Rationalization of Consciousness: A Mereological Reconstruction of Husserl’s Fifth Logical Investigation

Before engaging with intentionality, the philosopher of mind must consider the intrinsic nature of psychological elements. Conscious states, contrary to ordinary and scientific objects, seem to penetrate each another in such a way that it becomes impossible to enumerate, class or organize through laws the various experiences at stake. In this context, how is a science of consciousness conceivable? How is it possible to apply the epistemological requirements of any science to a domain whose ontological nature contradicts such demands? The paper reconstructs Husserl’s solution to this issue in the Fifth Logical Investigation. I show how his appeal to the mereological framework of the Third Investigation gives him the tools to rationalize the domain of the mind and to establish phenomenology as an authentic science of consciousness. I first demonstrate that the very task of phenomenological investigations is defined in mereological terms. I then reconstruct the issue regarding the inclusion of the intentional object within the act, by exposing the nuances of the Husserlian position in this famous controversy. In a last part, I show how mereological concepts are at the core of the Husserlian reinterpretation of the Brentanian thesis according to which all acts are presentations or based on presentations.