Who knows? The guy was not a really good teacher. His student Plato ignored the meaning of what he said about learning to write a book on it. A major point of the book was that reading the book was pointless because it was a form of sophism.
Before I am downvoted into oblivion, the above text is half joking and half serious. Socrates in Plato’s Republic really does make the case that formal training via methods intended to teach is pointless by comparing education to training horses. I made that point in my college philosophy class hoping the professor would skip it on the basis that it was a bad book (my thoughts on a book that suggested you could not learn its material by being lead to it - see the cave analogy). The professor then stopped the entire class to try to make sure everyone understood the point and then continued as if the material was not criticizing him.
