The succinct demolition of the labor theory of value in this section is positively one of my favorite bits of 'preaching' in any work. I just love that some guy writing a short novel is able to destroy such a core tenet of marxism in such a short example (even with the dressing up he gives it) that it wouldn't even meet length requirements for a middle school paper. Dubois has a lot of great bits throughout the book but that and the bit in the second chapter about 'violence has settled more things than anything else in history' really stick with me.

Across these chapters (and the whole book really), Heinlen is trying to get across that the value of a thing is based on not only what it gets you, but also what you have to give up for it. The training the M I cadets go through seems needlessly harsh both to the troopers and (I'd imagine) the readers. Requiring cadets to go through two day-long marches with no food or shelter provided? Live bullets in training exercises? Dropping cadets naked in the wilderness with no supervision for survival training? These actions seem barbaric to a civilian, but they have add value both in what they cost the cadets, and the effectiveness of the lessons they teach.

One other thing I'd like to mention that I haven't seen anyone cover in this discussion (though I believe someone brought it up in the previous one) is the point made about the purpose of war not being to kill your enemy, but to make them do what you want. I think this is often something that is forgotten by both civilians and officials in modern times, both in the sense of not enacting policies conducive of accomplishing the given goals of a war, being unwilling to commit to the actions that will accomplish those goals.