Critias agrees that maybe they have simply been asking wisdom to do too much. But then again, Socrates continues, it may be that they have been "inquiring to no purpose" at all, since even the new, more practical definition of wisdom (that it facilitates practical knowledge through knowledge about knowledge) still seems to have "strange consequences." Even if knowledge of knowledge (wisdom) were to be put in charge of assigning people in the state to specific jobs according to their practical knowledge and barring people from doing what they are ignorant of, the benefits might not be that great. Critias professes amazement at this, and Socrates admits that he's not sure of himself—it's just a thought he had, and must express.
Socrates proceeds to express this thought by recounting a "dream." He imagines that wisdom "has absolute sway over us," and that everything in the state—from health to the navy—is therefore perfect (since no one is doing what he is ignorant of). Even prophecy becomes a matter of wisdom. But, even with this vision of the absolute control of knowledge, Socrates finds himself unconvinced that we would truly be happy in such circumstances. Critias replies that we certainly would. Socrates proceeds again to ask what this governing "knowledge" is of, running through a number of practical possibilities (such as "shoemaking") that Critias rejects.
In that case, asks Socrates, who is it that is made happy without the functioning of practical knowledge? Even if there was a man with an all-seeing knowledge of past, present, and future (a kind of super-prophet), what specific knowledge—of the past, of the future, of playing at dice, of computation, of health, etc.—which of these brings him happiness? Critias answers that it is the knowledge that allows him to distinguish between good and evil. In this case, objects Socrates, all along we should have been looking not for a definition of wisdom or of temperance (a "science of science"), but rather for a specific science, such as the "science of good," or the "science of human advantage."
Socrates remarks that this "science of advantage" still seems to be necessary to every other science, even though it is no longer the all-encompassing "science of sciences" that had been formulated before. Critias suggests that the two (the science of advantage and the "science of science") are almost the same thing: in as much as wisdom rules over all the sciences and arts, it will also control this science of advantage and make sure that everything is beneficial. But Socrates reiterates again that pure wisdom, the knowledge of knowledge itself, cannot itself give us anything specific: medicine, not pure wisdom, gives us health, and the science of advantage, not wisdom itself, gives us advantage or benefit. Critias concedes the point.
Socrates concludes, at this point, that the whole inquiry has been useless. He and Critias have made a number of "concessions" that were not at all proven: chiefly, that there is in fact a science of science, and that it is not totally irrational to say that a man might know what he does not know. Even with these concessions, however, the argument has still foundered, this time on the lack of evidence that wisdom has any utility, any identifiable, practical benefit. Nonetheless, Socrates doesn't think such discussion is ever a waste of time. But he feels bad for Charmides, he says, since it appears that the beautiful youth's temperance of soul will have no practical benefit. In particular, Socrates laments, it appears that the Thracian charm to produce temperance is actually worthless, since temperance seems to have no effect.
In truth, though, says Socrates, he believes that he is just a bad inquirer, and that Charmides should rest assured that wisdom or temperance is truly a great good. Charmides replies that he surely cannot discover if he has temperance, since two wise men like Critias and Socrates cannot even define what it is. But, he says that he is willing to be "charmed" every day by Socrates until the matter is worked out. Critias backs up this choice, and Charmides becomes Socrates's pupil, "following him and not deserting him."
The crisis encountered at the end of Section Four (how can knowledge of knowledge have any effect on specific knowledge and specific benefits?) begins here to destroy the inquiry at every turn. Socrates seemed to have reached a promising (though undeveloped) stop-gap at the end of Section Five: knowledge of knowledge does not yield concrete benefits directly, but acts as a sort of guiding force facilitating "inquiry" into specific, concrete issues.
But Socrates seems unable to accept this. His reasons for switching almost immediately from the suggestion that he and Critias have been asking too much of wisdom to the suggestion that they have been on the wrong track are unclear, mired in layers of directionless argument, repetition, and even a "dream." At the beginning of this section, Socrates simply says that he is unconvinced that any "benefit" would really derive from the rule of temperance (knowledge of knowledge) over the state. But he is not using any adjusted, less idealistic version of the definition of temperance. This means that he is saying nothing he did not already just say about the apparent impossibility of the perfect state, ruled by self-knowledge. The transition, then, is unclear, and the argument seems to become adrift in perplexity.
Things do not improve when Socrates makes his next step depend on recourse to a sort of daydream, again about the ideal state (thus marking a further repetition of the same argument). The first new thing we are given to consider is the term "happiness"; Socrates's anxiety is simply that even the most perfect image of the wisdom-governed state fails to convince him that people would go around happy. In a sense, this anxiety is remarkable and touching, considering Plato's later argument, in the Republic, that just such a state would yield universal happiness (the way that a self-knowing, temperate soul will yield a happy person). In another sense, such anxiety is puzzling: coming seemingly from nowhere, and seemingly dismissing the whole set of terminology constructed thus far, it simply launches the foundering dialogue, with a jerky start, toward further confusion.
In the rest of the muddled argument, the sticking point is always essentially the same—nothing about the generalized idea of knowledge about knowledge seems to connect to the concrete benefits that make us happy. Getting nowhere on this point, Socrates finally gives up, both on the specific aim of showing how temperance as self-knowledge can be useful and on the whole project of defining temperance.
The final paragraphs of the dialogue are fascinating and mysterious, a rapid shift triggered largely by the newly affirmed presence of Charmides. Despite the failure of the argument, Charmides is "charmed" enough to forget about the mystical Thracian cure and simply come every day to learn from Socrates. This result is notable along two lines: with the return of desire into a dying argument we get a sense that what really matters in this whole process is not knowledge but successful wooing; and it suggests, in Charmides's being won over by the failed argument, that the process of argument is the key both to knowledge and to love. Charmides renews the whole of philosophy at this moment of failure: he will be Socrates's student, and the two will pursue temperance together.
The ending, however, is slightly darker and more perplexing than this. Along with issues of love, issues of dominance return to the fore in a profoundly unsettled way. Charmides dominated Socrates at the beginning of the dialogue, and was then dominated by Socrates. Here, at the end, he is almost made into Socrates's servant, swearing, at Critias's urging, to follow and obey him. But, in the last few lines, there is a further twist, a dialogue that seems to condense all the mystery of personal relations that underlie the pure union of souls (now broken) that philosophical dialogue is supposed to effect. The playful conceit has to do with political conspiracy and coup d'etat, but also references Socrates's own eventual death at the hands of a hostile court. At the same time, this reads fittingly as a flirtation in the text as well.