So, it's sort of a communal "it takes a village" approach with the word marriage and some seniority rules attached?

Does overpopulation as a potential threat to survival ever enter the equation?

(Stipulated: there are individuals, both sexes, who prefer to live alone. This is racially self-correcting.)

It's the word "racially" in this that confuses me. Was he attributing the preference to a racially genetic trait?

Aurelia, racially, I think is meant not as what race are you, but racially correcting, like correcting within the entire human race.

So, it's sort of a communal "it takes a village" approach with the word marriage and some seniority rules attached?

Right. It's a gedankenexperiment. What happens if you do Australia all over again, but this time without the Christianity and with women having the right of sexual refusal? Heinlein's thesis is that you come up with lots of alternate forms of marriage, most of them polygynous.

I think he meant racially as in "human race". But I'm guessing.

Does overpopulation as a potential threat to survival ever enter the equation?

He does a spiel about Mathusian theory in TSbtS, um, and in a lot of his stories, overcrowding is a main reason humans colonize the Moon, and go into space in general. And in I Will Fear No Evil, people get assigned how many kids they're allowed to have.

But he implies that the people who follow the Luna-type marriages are Just Too Smart to overpopulate.

EDIT

MALTHUSIAN theory

And in I Will Fear No Evil, people get assigned how many kids they're allowed to have.

Also in Podkayne of Mars. Whose point, according to the unabridged edition, was that Silly Girls Shouldn't Expect To Have It All. I think I'll stick to the abridged edition, ta ever so.

human race

Okay, that makes more sense.

Oh, that made me so mad. And I loved the book up to that point.

But he implies that the people who follow the Luna-type marriages are Just Too Smart to overpopulate.

I think it has less to do with being smart and more with helping raise like 20 other people's kids from the minute one joins the daisy chain. Best birth control method, ever.

I think Heinlein enjoyed provoking people--provoking them into thinking about things they took for granted, their assumptions, and possible alternatives.

I don't think he necessarily expected his readers to agree with what he wrote. I seem to recall remarks in an essay (I'm not sure if it was by Heinlein or about him) about not mistaking a storyteller's product for his personal opinions, but I can't find the quote.

I think Heinlein wanted readers to think about why they agreed or disagreed.

In TMiaHM he did that with the purpose, form, and function of government on a small scale (the family) and on a large scale (the nation).

There are two quotes that have stuck with me since I first read TMiaHM as a teenager:

"Under what circumstances is it moral for a group to do that which is not moral for a member of that group to do alone?"

and

"Don't reject the idea merely because it seems preposterous--think about it!" [emphasis mine]