Never crowd youngsters about their private affairs - sex especially. When they are growing up, they are nerve ends all over, and resent (quite properly) any invasion of their privacy. Oh, sure, they'll make mistakes - but that's their business, not yours. (You made your own mistakes, did you not?)

Never cast pearls before swine.

If God existed (a question concerning which Jubal maintained a meticulous intellectual neutrality) and if He desired to be worshiped (a proposition which Jubal found inherently improbable but conceivably possible in the dim light of his own ignorance), then (stipulating affirmatively both the above) it nevertheless seemed wildly unlikely to Jubal to the point of reductio ad absurdum that a God potent to shape galaxies would be titillated and swayed by the whoop-te-do nonsense the Fosterites offered Him as "worship.

When the citizens of a nation will no longer volunteer to defend it, then it is probably not worth saving. No nation has the right to survive with conscript troops, and in the long run, no nation ever has.

Since survival is the sine qua non, I now define the "moral behavior" as "behavior that tends toward survival".

A handy short definition of almost all science fiction might read: realistic speculation about possible future events, based solidly on adequate knowledge of the real world, past and present, and on a thorough understanding of the nature and significance of the scientific method.

There were many, many times thereafter that Don regretted having enlisted - but so has every man who ever volunteered for military service.