In chapter four, we turned to Husserl's discussions of association, habitualization, and apperception in order to explain the function of far retention. By doing so, we already entered into a discussion of passive genesis. Here we will return to the notion of apperception (and, implicitly, appresentation) as our guide to understanding passive genesis, not only because it is a notion with which we are already familiar, but also because Husserl himself says essentially that an understanding of the genesis of consciousness requires an understanding of apperception: