What distinguishes the Socrates of the early from the Socrates of the middle dialogues? According to a well-known opinion, the “dividing line” lies in the difference between the Socratic and the Platonic theory of action. Whereas for the Platonic Socrates of the early dialogues, all desires are good-dependent, for the Platonic Socrates of the middle dialogues, there are good-independent desires. The paper argues first (I) that this “dividing line” is blurred in the "Symposium", and second (II) that we have in the "Symposium" a more distinctive dividing line, namely the introduction of the separate existence of the idea of beauty. This introduction by Diotima/Plato of separate ideas and the lack of (noetic) understanding of separate ideas – here the idea of beauty – by Socrates may have been the limit not only of the Socrates of the early Platonic dialogues, but of the historical Socrates as well.