The theme of "Wisdom and Knowledge" in Agamemnon mainly centers around the Chorus's claim that Zeus makes mortals "Suffer and learn" (177). This phrase could be interpreted to mean "learning happens through suffering" or even, more neutrally, "learning happens through experience." Do you think this is true? Think about it: say you're trying to communicate to your friend that his or her new girlfriend or boyfriend is a total jerk. If the Chorus is right, and learning only happens through suffering, your friend will probably tell you, "I don't believe you," or "It's not really so bad," or something like that. Then, a few months later, after suffering through enough of his or her significant other's jerkiness, your friend might come up to you and say, "You know what, you were right; I just didn't believe you at the time."
We've probably all had this experience. But the big question that Aeschylus's play is asking is whether learning always happens through experience, or just part of the time. How is this relevant to the other themes in the play? Think about it: if you think people only learn through suffering, then might want to punish them for crimes by doing the same thing back to them, right? In this way, this theme links up to the ideas of revenge and justice. Similarly, if you only learn what's going to happen by experiencing it, then prophecies about the future can't help you. In this way, this theme links up to the problem of fate and free will.
Aeschylus's play shows that humans can only learn through experience.