Laches begins with Lysimachus saying, “You have seen the exhibition of the man fighting in armor,” a rather bland opening but, as with all the opening lines in Plato’s dialogues, one worth considering. In the first place, beginning a dialogue just after someone has given a speech or demonstration is a device Plato employs in other dialogues (Hippias Minor, Gorgias, and Protagoras), and it suggests that the activity that has preceded the dialogue is not, for whatever reason, to be “recorded” as part of the dialogue. The discussion that follows this exhibition is the important thing. If, having watched a film or television program or attended a ballgame or concert, you imagine yourself saying to a friend, “Now, let’s get down to the important thing and talk about what we’ve just seen and heard,” then you will have a fair idea of the mood Plato is trying to set at the beginning of Laches.
From the opening line we also note that Lysimachus says that Nicias and Laches, who are both generals in the Athenian army, have seen something. But what have they seen? They have seen a man demonstrating what it is like to fight in armor; that much is clear. It is equally clear that they have not seen a man actually fighting in armor. The man demonstrating what fighting in armor is like is not himself fighting in battle. He is only simulating what it is like to fight in armor. Could anyone who has observed this demonstration make a reasonable judgment about whether learning to fight in armor is a good use of one’s time and money? Maybe, but it is difficult to say. Nicias thinks so, but Laches points out that those masters of fighting, the Spartans (Lacedaemonians), certainly don’t go in for it (182e).
Although the dialogue is known as Plato’s attempt to define “courage,” it does not start, as many similar dialogues do, by asking that question straight out. The first question of the dialogue is whether Aristides and Thucydides should be taught to fight in armor, but that question, through Socrates’ leading, turns into a discussion of the kind of knowledge that benefits the souls of youths (185e). Socrates says that this issue is the really important one because getting clear about it will help us both identify good teachers and know what kinds of things good teachers will teach. Laches and Nicias agree with Socrates that if they can identify a teacher capable of teaching virtue they will have found a good teacher for the sons of Lysimachus and Melesias.
To our shock and, perhaps, dismay, Socrates admits that he has never had a teacher of the art of virtue nor does he have one now. How strange that a man most noted for his interest in virtue has no one to teach him about the subject! This is not for his lack of trying, though Socrates admits that it might be for lack of money: he cannot afford to pay the sophists, who claim to be able to teach virtue. But given the way Socrates refutes the sophists—Hippias, Gorgias, and Protagoras, for example—with whom he interacts in Plato’s dialogues, it does not seem likely that they would have been able to teach Socrates virtue even if he could have afforded their fees.
Through a series of interrelated assumptions and arguments (186c–190d), the discussion shifts from the question Who is a good teacher of virtue? to What is courage? Though there is not enough space here to work through these points, it is important for the reader to sort out the details of this shift, paying special attention to Nicias’s observation that “where Socrates was, the argument would soon pass from our sons to ourselves” (188b–c). Even if we start a discussion about what is best for someone else, it is impossible to have a good discussion without being forced to examine our own lives and beliefs. When we emerge on the other side of the shift, Socrates presses Nicias and Laches on what they think is a good answer to the question What is courage? (If you think that giving a good answer to this is easy, then by all means try to give an answer—but make sure it is what you think and not simply one parroted from the nearest friend or dictionary.)
From this point of the dialogue to the end (190d–201c), Socrates, Nicias, and Laches argue about what courage is. Their discussion takes up only ten pages, but there is much more in those ten pages than one could possibly discuss in an introduction. So let us note two things about the dialogue’s namesake that might be helpful in reading the dialogue.
The first point is the one aspect of Laches distinguishes it from every other dialogue Plato wrote: Only in Laches do we find characters other than Socrates really arguing with each other. In other dialogues, we often read about Socrates arguing with one other person. Even if there are a number of people involved in the dialogue, they almost always take turns discussing with Socrates. They hardly ever argue with each other for an extended period of time. In Laches, however, there are a number of passages where Nicias and Laches mix it up and, to greater and lesser degrees, ignore Socrates. The discussion in Laches tends to have the character of a melee. What should we make of this?
A good conversation is spirited. No one likes a boring discussion. But the spiritedness of Laches in this verbal brawl is dangerously ambiguous. After being refuted by Socrates, he says that “the spirit of controversy has been aroused in me by what has been said” (194a). This excitement is fortunate if Laches takes his own ignorance of what courage is to be his opponent, but if he mistakes Socrates or Nicias for his true opponent, then he will care less about acquiring knowledge than about refuting his conversation partners. That won’t do anyone any good.
The second point is Laches’ assertion, in response to Nicias’s definition of courage as a certain kind of knowledge, that Nicias cannot be correct because “surely courage is one thing, and wisdom another” (195a). The danger in Laches’ assertion is that he is so sure that one thing cannot be another he is blind to the possibility that the two things may not be so different after all. Why couldn’t courage be a kind of knowledge? Perhaps we have a mental image of courage—a courageous person, William Wallace or Rosa Parks, perhaps—that differs from what we think of when we hear “knowledge.” We must, however, examine our preconceptions about courage and knowledge if we are to have any hope of success, and we need a discussion with good, intelligent, courageous friends who will challenge our preconceptions and, like Socrates, lead us to examine our own lives.
Now then, having read these comments as if they were some kind of speech or demonstration, the reader should take a cue from the opening of Laches and proceed first to read the discussion set down by Plato and then to discuss the reading with one’s friends.
 Cf. Nicias’s comment about fighting “in actual battle” (182a) and Laches’ comment that people who teach fighting in armor do not do well “in actual battle” (183d).