No discussion of an experiment is complete without some look at the results. If this lecture were a lab report, I'd divide the discussion into purpose, experiment, and results. We can't dismiss his answers as unreasonable because by definition they are grounded in reason. The answer claims to provide a rational basis for moral life.
Justice equals liberty equals happiness.
Injustice equals enslavement. More on the metaphysics from Norm next week. What's important is that Plato thinks that all this heady stuff is actually knowable. Socrates is arrogant on this stuff. Hush, he seems to say.