  In the opinion of most scholars, the seminal influence on all of Plato's thinking was Socrates. However, it appears from the writings of Plato, as well as those of the historian Xenophon and the comic poet Aristophanes, that Socrates was almost exclusively interested in ethics. This is not to say that metaphysical or epistemological issues were of no concern to him. Rather, these sources convey the impression that Socrates was not particularly interested in articulating a metaphysical or epistemological  theory (see Vlastos 1991a).  Rather, concerned with caring for the soul so that one might live happily (Apology 29d-30b), he uses both epistemological and metaphysical theses in search of answers to his ethical questions. However, it is not easy to distinguish when one is engaged in metaphysical theorizing from when is merely using metaphysical notions. The claim that Socrates was not a metaphysician or epistemologist is particularly hard to evaluate, for we have basically only Plato's dialogues as evidence. Since Plato uses Socrates as a mouthpiece in many of his writings, readers are forced to ask when or whether one is reading the doctrines of Socrates, or Plato, or neither. This ‘Socratic question’ is intimately involved with the question of Plato's development and the chronology of his dialogues.