Before exploring the six key topics, we should consider the linguistic and literary forms in which Greek philosophy was expressed and its logic developed. The search for truth, for an acceptable explanation of how things are, embracing the world and the relation of the state and the individual to it, was stimulated right from the start by the spirit of competition. This was aided to a considerable extent by the spread of literacy. Once new ideas were written down they could be published abroad, and were then available for analysis, criticism, defence, modification and improvement, in an extraordinarily fast movement of arguments and counter-arguments across the Mediterranean. We find, however, that individual philosophers chose and developed distinctive literary forms in both poetry and prose as appropriate to their ways of thinking. Not only do we have different dialects, especially Ionic from the coast and islands of Asia Minor and Attic for philosophers based in Athens, but prose could be answered with epic verse, and verse countered with prose, the verse sometimes prosaic and the prose in a variety of styles. Some set out their philosophy in enigmatic sentences, or as puzzles and dilemmas, or used the tricks and flourishes learnt from rhetoric. Plato, for the most part, preferred a dialogue form as closest to actual conversation, which could show an argument advancing step by step, but he also took great care in setting the scene, and, where the material was unsuitable for logical analysis, he used a narrative form in extraordinary myths.