SOCRATES
We know a few things about Socrates.

1. Plato (427-347 BCE) was a younger contemporary and student of Socrates (470-399 BCE).
2. Socrates was the first truly systematic (Western) philosopher.
3. Socrates inspired Plato and other subsequent philosophers, including Aristotle (Metaphysics i 6, xiii 4) (who had some independent evidence about Socrates's views), and many Athenian youths, including the iconoclast aristocrats Critias and Alcibiades (associated with the Thirty Tyrants).
4. Socrates was brought to trial on charges of impiety and corrupting the youth of Athens, convicted, and executed in 399.
5. We have no record that Socrates ever wrote anything.

• Plato's Socrates is both paradoxical and ironic; Xenophon's is neither.
• Plato's Socrates may win arguments, but rarely persuades his opponent; Xenophon's Socrates persuades all those with whom he argues.
• Plato's Socrates is concerned primarily with human affairs; Xenophon's Socrates is concerned with theology.
• Plato's Socrates denies that one should ever harm one's enemies in flat contradiction of then conventional Greek (e.g. Homeric) moral views; Xenophon's Socrates never contradicts Greek popular morality.

SOCRATES AND PLATO
Attention to the content and style of Plato's dialogues and the testimony of Aristotle (Metaphysics i 6; xiii 4) allows us divide the dialogues reasonably well into four groups.

• Early or Socratic Dialogues
• Apology, Crito, Euthyphro, Laches, Charmides, Euthydemus, and Lysis
• Transitional Dialogues
• Protagoras and Gorgias
• Middle or Platonic Dialogues
• Meno, Phaedo, Republic, Symposium, Phaedrus, Parmenides, and Theaetetus
• Later Platonic Dialogues
• Timaeus, Sophist, Statesman, Philebus, and Laws

SOCRATIC BACKGROUND
Understanding Socrates's significance requires understanding his intellectual innovation, which requires seeing his ethical thought against the background of prevailing and rival moral conceptions.

HOMER
Even if Homer does not self-consciously develop ethical theories, his description of heroic action seems to make assumptions about what sort of people and actions are admirable and good.  There are several points worth noting about the Homeric hero.

• The good person (agathos) is the Homeric hero -- a successful (male) warrior of aristocratic birth and upbringing who displays courage and power and is successful in battle.
• A Homeric hero depends upon external goods.  (a) Though virtues of character are admirable, they are not necessary to be agathos. (b) e-goods (strength, social status, success, and social recognition) appear to be both necessary and sufficient to be agathos.
• The Homeric hero is agent-centered. Though the agathos should protect dependents and supplicants, this is because it demonstrates his power, not because they have a legitimate claim on him.
• The Homeric conception is unstable: (a) being agathos depends upon vulnerable e-goods; (b) it is socially unstable, because it pits heroes against each other in divisive struggles over scarce e-goods.
• The Homeric world-view reflects an anthropomorphic polytheism.  Natural events and human affairs are to be explained as the operation and interaction of various gods, who are themselves large-scale versions of the Homeric heroes.

SOPHISTIC AND RHETORIC
Part of understanding Socrates's innovation requires contrasting his methods with other superficially similar methods.  Like Socratic inquiry, both rhetoric and sophistic involve public inquiry into ethical and political questions, and both can involve dialogue in which the interlocutor's claims are confuted.

Rhetoricians offered to teach the art of persuasion.  This might seem to be an especially valuable skill for members of the democratic Assembly who sought to shape the political agenda of Athens or hold political office.  Like Socratic dialectical inquiry, rhetoric depends on the beliefs of its audience.  But Socrates believes that whereas dialectic aims at truth -- in particular, truth about how best to live -- rhetoric aims at securing the audience's agreement or approval of the orator's objectives (Euthyd 272b1-2 and 8, 275d5-278e, 305b-306c).  Moreover, whereas philosophy aims to benefit its audience, rhetoric aims to flatter and, hence, to please its audience (G 462b-465d, 502e-503d).

As a rule, rhetoricians did not claim to educate people or make them better.  By contrast, the sophists did.  A feature of some forms of sophistic that might arouse hostility is eristic method, and Socrates clearly sought to distinguish his own method from eristic.  Most generally, eristic involves various debater's tricks that exploit ambiguities or unclarities in an interlocutor's claims, typically unfairly, in order to confound him.  Like rhetoric and unlike Socratic dialectic, eristic aims at victory in debate, rather than the truth (272ab).

Still another reason for distrust of sophistic is that some sophists hold moral views that appear subversive of the cooperative virtues on which the stability of Athenian democracy depends.  For instance, it is sometimes thought that the sort of challenge to a cooperative conception of the virtues expressed by Callicles in the Gorgias and Thrasymachus in the Republic should be understood to be a product of sophistic teaching.

But not all sophists are critics of conventional morality.  On Plato's view, many sophists merely repeat common moral convictions without examining them, much less revising them.  Protagoras is an important case in point.  Indeed, Protagoras famously thinks that "a man is the measure of all things, of those that are, of how they are, and of those that are not, of how they are not" and that "as things appear to each of us, so they are" (Tht 152a).  Though Socrates's dialectical methods also begin from common beliefs, he believes that if practiced the right way it can be used to distinguish between true and false beliefs, especially about how best to live.  Moreover, he thinks his methods allow him to show that Homer, Callicles, and Thrasymachus are wrong and that the cooperative virtues are essential to leading a good life.

SOCRATIC PARADOXES
Socrates is famous for some striking and sometimes paradoxical commitments.

1. Moral Knowledge and Socratic Ignorance.  (a) Socrates seems to believe that we should expect to find expertise in matters ethical, as in other crafts (Cri 46c 47d); (b) yet he claims to be ignorant himself and believes that others know even less than he does (Ap 19c, 20c e, 21d, 33b); (c) yet he seems quite confident about some moral claims and is willing to rely on them in arguing with others (Ap 17bc, 28b, 29b, 41e).  Though (a) and (c) are consistent, both appear to conflict with (b).
2. Virtue and Happiness. Socrates believes that (a) an agent's own happiness (eudaimonia) is or ought to be the ultimate end of all of her action (La 181ce, 192d; Ch 169b, 173e; Eud 278e with 280b6, 282a), yet he believes that (b) familiar, other-regarding virtues (e.g. courage and justice) are admirable.  (a) and (b) commit him to other claims.  He believes that (c) one should be virtuous at any price (Ap 28b, 29b, 32bc; Cri 48cd, 49b).  In fact, Socrates believes that (d) virtue (e.g. temperance, justice, courage, piety, wisdom) is both necessary and sufficient for the agent's happiness (Ap 29b 30b, 30d, 36c, 41d e).  This implies that (e) a good person cannot be harmed (Ap 41cd) and that (f) one cannot profit by vice (e.g. injustice).
3. Virtue is Knowledge.  This cognitive account of virtue seems to imply several things: (a) that knowledge is necessary for virtue (La 192cd; Ch 159a), and by (1b), that no one is virtuous (because no one has the requisite knowledge); (b) that knowledge is sufficient for virtue (Ap 25c 26a, 37a), which implies that weakness of will is impossible (you can't know what virtue requires without acting virtuously); and (c) the unity of the virtues (La 199e), which implies that you cannot have one virtue without the others.