Plato’s Lovers (erastai) is, today, considered a spurious dialogue. It has come down to us as Platonic, though it is dubiously part of the modern canon. In latter manuscripts it was called “Rival Lovers”.
It recounts a conversation between Socrates and young boys, in the “place of Dionysus”, as they discuss spherical geometries of Pre-Socratic thinkers, perhaps of Anaxagoras or Oinopides. Socrates takes a seat next to one of the pederastic lovers watching. He quickly inserts himself into the discussion and focuses on the boy who seems more interested in philosophy.
The question in the dialogue is whether philosophy is noble, however the discussion quickly turns to the question of what philosophy is. In summary: they agree that philosophy is noble, that they are both philosophers, and that philosophy is good, the good are useful and the wicked useless (137a). The brief dialogue concludes in denying the notion that philosophy is for the useful is ultimately rejected.