"On the Pedagogical Motive for Esoteric Writing", Arthur Melzer 2007:

What evidence and what arguments can be produced in support of the controversial suggestion, first made by Leo Strauss now over 65 years ago, that most earlier philosophers wrote esoterically and, what is more, that they did so, not merely from fear of persecution, but with an eye to enhancing their pedagogical effectiveness? I argue here that the inherent paradoxes of philosophical education combined with the inherent shortcomings of writing led many earlier thinkers to see the pedagogical necessity of something like the “Socratic method.” And esoteric writing—a rhetoric of riddling concealment—is the closest literary approximation to the Socratic method.

My opinion of the general Straussian suggestion has been heightened by the recent claims of finding musical structures in Plato's dialogues, who had been one of the major proposed users of esotericism.