Some of Plato's dialogues are framed by human elements. The clearest example of this is Phaedo, wherein Socrates dismisses his wife Xanthippe from the prison at the beginning of the dialogue, and again towards the end. The frame elements suggest that Socrates' relationship with his disciples, who mourn the imminent loss of their spiritual "father" is more important to him than his actual family. In this dialogue, an entire chorus of people is said to be silently listening to a very long conversation, and apparently, saying nothing.Other dialogues, such as Euthyphro and Crito, involve only two characters who are not said to be overheard by anyone else. The characters are meant to be compared and contrasted. Socrates is more like Euthyphro (whom he mocks) than he thinks. Both are pious men whose knowledge of god's will comes from different sources - Euthyphro reads myths and takes them literally, while Socrates relies on divine voices in his head. Socrates is less compatible with his friend Crito than he thinks, and even says that people who are so morally at odds ought to despise each other. Sometimes characters pop in and out of a dialogue, as a slave and an aristocrat (Anytus) in the Meno.Two of Plato's dialogues are better described as monologues. They are called Apology, and Menexenus. Gorgias, Protagoras and Lesser Hippias are structurally similar: each depicts Socrates being invited to converse with a well-known wise man who is visiting Athens. Lysis and Charmides are twin dialogues that picture Socrates chatting with boys who require attendants, slaves or older male relations who are appointed to walk them to and from their lessons at school. Phaedrus and the Symposium are a pair of dialogues linked by the theme of man-boy love.Many other dialogues ascribed to Plato also use the Socratic character, but do not share this pronounced concern for virtue. In these dialogues, Plato uses Socrates as a mere name, a voice-marker who does not have the distinctive, self-deprecating wit of the important dialogues. The metaphysical dialogues attributed to Plato do not contain material of human interest, but are very abstract and read by specialists.The dialogues have been divided by influential scholarship into the early, middle and late periods. The late Princeton scholar and classicist, Gregory Vlastos argued that the Euthyphro, Apology, Crito and Phaedo were written first and are a more or less historical record of the philosophy of the historical character Socrates. Vlastos' aim was to account for the obvious contradictions among dialogues. He argues that Plato's early dialogues represent Socratic philosophy, and that in the so-called middle and later dialogues, Plato expresses his own, quite different philosophy. Even Vlastos admitted that this division is not well-supported by the dialogues themselves. Nevertheless, his theory continues to be extremely influential.Early dialogues Socrates figures in all of these, and they are considered the most faithful representations of the historical Socrates; hence they are also called the Socratic dialogues. Most of them consist of Socrates discussing a subject, often an ethical one (friendship, piety) with a friend or with someone presumed to be an expert on it. Through a series of questions he will show that apparently they don't understand it at all. It is left to the reader to figure out if "he" really understands "it". This makes these dialogues "indirect" teachings. This period also includes several pieces surrounding the trial and execution of Socrates.Apology Crito Charmides Laches Lysis Euthyphro Menexenus Lesser Hippias Ion The following are variously considered transitional or middle period dialogues:Gorgias Protagoras MenoMiddle dialogues Late in the early dialogues Plato's Socrates actually begins supplying answers to some of the questions he asks, or putting forth positive doctrines. This is generally seen as the first appearance of Plato's own views. The first of these, that goodness is wisdom and that no one does evil willingly, was perhaps Socrates' own view. What becomes most prominent in the middle dialogues is the idea that knowledge comes of grasping unchanging forms or essences, paired with the attempts to investigate such essences. The immortality of the soul, and specific doctrines about justice, truth, and beauty, begin appearing here. The Symposium and the Republic are considered the centrepieces of Plato's middle period.Euthydemus Cratylus Phaedo Phaedrus Symposium Republic Theaetetus ParmenidesLate dialogues The Parmenides presents a series of criticisms of the theory of Forms which are widely taken to indicate Plato's abandonment of the doctrine. Some recent publications (e.g., Meinwald (1991)) have challenged this characterisation. In most of the remaining dialogues the theory is either absent or at least appears under a different guise in discussions about kinds or classes of things (the Timaeus may be an important, and hence controversially placed, exception). Socrates is either absent or a minor figure in the discussion. An apparently new method for doing dialectic known as "collection and division" is also featured, most notably in the Sophist and Statesman, explicitly for the first time in the Phaedrus, and possibly in the Philebus. A basic description of collection and division would go as follows: interlocutors attempt to discern the similarities and differences among things in order to get clear idea about what they in fact are. One understanding, suggested in some passages of the Sophist, is that this is what philosophy is always in the business of doing, and is doing even in the early dialogues.The late dialogues are also an important place to look for Plato's mature thought on most of the issues dealt with in the earlier dialogues. There is much work still to be done by scholars on the working out of what these views are. The later works are agreed to be difficult and challenging pieces of philosophy. On the whole they are more sober and logical than earlier works, but may hold out the promise of steps towards a solution to problems which were systematically laid out in prior works.Sophist Statesman Philebus Timaeus Critias Laws