If we set out here to consider Husserl's phenomenology as the foundation of natural science, we do not mean to imply or suggest that Husserl's philosophy is confined to such a foundation. According to its purpose and realization, Husserl's monumental opus is certainly more than that. For it aims at nothing less than the phenomenological clarification of knowledge as such, the critical elucidation and the phenomenological foundation of rational knowledge on the whole.