(Introduction) The question of heterogeneity does not appear at first glance to be a genuinely phenomenological problem and not even a problem in general. It seems to go without saying that there is “coupling” (Paarung), association, fusion, synthesis or in general any form connection between different data of consciousness, all as it seems obvious (at least from Husserl) that there must be objectities so that we can talk about knowledge and truth.
After Kant we got so used to synthetic formations that we hardly think of their possibilities in principle and the problems that these are called upon to resolve. Phenomenology does nothing else but describing the synthetic process, starting with its most elementary (pre-reflective) levels, aiming thus to completely elucidate the constitution of the objectity and, by that, the functioning and the rights of reason. Now, such elucidation does not only involve an approach aimed at the how, but also, the why of this process. In other words, our attention and our theoretical interest must be directed not only towards the course of the constitutive synthesis, but also on what motivates her intrinsically. Questions like "why should he be there in general an objectity? " or "is it principally possible to associate in one form or another data belonging to to the same class or to different classes? ”, questions which are de jure and which therefore refer rather to the legality of the constitution than its more or less contingent functioning, cannot in any way be excluded from the scope of the phenomenological questioning. As much as the epistemological ideal of phenomenological description required above all that it avoid any form of abstraction and idealization, this class of questions is, if not excluded, at least left in shadow.