Okay, so I'm a bit science and religion obsessed academically, but I think the discussion here could be fruitful. This really goes back to the class discussion about the "scientifically verifiable theory of morals" (p. 118). I think Riceguy20 is totally right to highlight the quote "Man has no moral instinct" (p. 117) as really important -- through the instrument of Mr. Dubois, Heinlein constructs the ultimate 'science trumps religion' universe. My interest derives also from Asimov's "Foundation", in which a branch of mathematics called "psychohistory" develops that governs nearly every part of life (to certain scale/degree).
In our present-day world, writers like Edward Wilson might suggest a
biological basis for morality, but even so we're still one step shy of explaining all subjects with symbolic logic. Repeatedly, such logic is the ultimate appeal in Starship Troopers. Assignments like "Bring to class a written proof, in symbolic logic" (p. 179) often follow many enormously important discussions in History and Moral Philosophy. This type of proof (or even just the suggestion that such a proof exists) seems to apparently putting the matter to rest; regardless of its controversial, political, and subjective nature.
Does this strike anyone else as a perversion of the humanities? Not everything can be an "exact science" (p. 182) with one right answer. I cherish needing different models (yeah, there's some truth in looking at morals as deriving purely from nature and nurture; but I also find much meaning from considering some transcendental role), so it frustrates me that Starship Troopers describes a 'one right, proovable, answer' world. Interestingly, your answers in such a universe are still going to depend on your initial assumptions... you can't prove everything. The biggest assumption made, that science works and teaches them Truth about the real world, can be neither proved or disproved, only debated and assumed.
Why might science fiction like ST or Foundation disregard any need for non-scientific truth? Yes, the intended audience might be more familiar with science as authority, but I don't think that's all there is going on here.
In all fairness to science fiction, I don't think that Starship Troopers provides a very representative model of the genre's descriptions of morality. Much of the best science fiction, and perhaps the best fiction in general, is that which creates situations which are morally complicated or ambiguous for the characters, and by extension the reader. I think, off the top of my head, of Ender's Game, constantly evaluating under what circumstances the ends justify the means, and under what circumstances one can be truly responsible.
I wish I'd read this post before I replied to another one - this is much more relevant to what I wanted to say, and I'm not going to write the same thing twice. Still, I will say that I also immediately thought of Asimov's psychohistory in relation to ST morality. It seems like the idea is basically the same - except that where the characters in Foundation use mathematics as a way to predict what others are going to do, ST characters use it to decide what they should do. Of course you are right that we have no system as yet to make such predictions/decisions, and we may never. Still, it at least seems plausible that we might someday, and to me the more important problem with this idea is the second one you mentioned, that any moral conclusions still depend on your assumptions.
To attempt to answer your last question, I think the audience is the answer - but more the broad audience of our society than the narrow one of SF readers. We believe in science. It is the foundation for our society and everything it has accomplished, good and bad. In ancient times, science meant thinking about what made sense and how things ought to be in a world that made sense. Then people decided using evidence worked better in a lot of areas. Now we are at the other extreme, where we want evidence for everything, from physics and biology to morality and the existence of God. ST's moral philosophy seems like the ultimate answer to a desire for an evidence - based theory of ethics.
Personally, I think that the "one scientific, provable truth; no religion" attitude simply helps Heinlein further the rest of his agenda in this book. The man served in the military and campaigned in favor of U.S. nuclear testing in the 50s-60s; clearly the military life of not asking questions, falling into line with the group, and speaking with one voice is being kind of glorified here.
In the world of Starship Troopers, all of the youth have this singular perspective pounded into their heads at school, to prevent the emergence of other ideas and models. Ironically, the class is called "History and Moral Philosophy", and philosophy is supposed to encourage the existence of multiple ideas. If Heinlein let alternate, possibly anti-military views have any strength, then the military would seem weaker to the outside world, ess glorious, and undeserving of the deference that it receives. I believe there is even one conversation between Zim and Captain Frankel, just after Heinrick has been flogged and kicked out, in which Frankel states: "Now we will have the consequences of him (Heinrick) being against us for the rest of his life, and telling other people what happened."
"Why might science fiction like ST or Foundation disregard any need for non-scientific truth?"
I find this comment very interesting, but I think the phrase needs to be a little clearer. What do you mean by "non-scientific truth"? Why should there be a need for it in anything, let alone in a genre based on the "hard" truths of science?
I will re-phrase the question: "Why should scientific theory be the predominant method by which these authors choose to justify their universes?"
I think the answer to that is easy enough. The body of knowledge based on scientific thought is the most reliable explanation we have so far of the way that our world works. It most reliably predicts future interactions. For example, the acceleration due to gravity can be very closely defined to be 9.81 m/s^2. If you measure an object in free-fall, assuming it has not reached terminal velocity and air resistance is not an issue, it will closely follow this acceleration. The object will reliably display this behavior time after time. Scientific laws predict future iterations of your test.
I do not believe that science can absolutely determine (though it may inform) morality, or predict emotional response (yet). But given the fact that science predicts the large majority of our interactions with the world to a great degree of accuracy, I think that the impulse to use hard scientific principles in all aspects of an authors' work is quite natural. Basic scientific theory is, in the two novels you mentioned, vastly over-applied, but the impulse itself is quite easily explained.
-CZ
And a really nice follow-on discussion! I'll look forward to seeing how your readings of this belief in the ultimate authority of scientific truth play out over the rest of the semester...