What makes a good quick explanation?
I can think of several possible criteria. The most obvious are that it should be quick and it should explain something. A lecture is, to most people, not quick; and a sound bite is, as often as not, not very explanatory. Political speeches, marketing pitches, and other such beasts are neither quick nor explanatory,
It's easy to measure the time someone talks, or the amount of paper
someone uses, to say something. It's much harder to measure the
explanatory quality of what is said. In one of Asimov's
Foundation books, an ambassador visits the Foundation
planet for a week or two, and everything he says is recorded.
Afterward an analysis is done, and it's revealed that once the
pleasantries, diversions, and self-contradictory things he said are
stripped away, the only information is We are going to attack
soon.
It made a good story point, but I have a hard time
imagining how such an analysis could be made rigorous. Still, some
sentences clearly convey more information than others. As one wit
advised technical writers the number of words you use divided by
the number of ideas should not tend toward infinity.
I think one hallmark of a good quick explanation is
concreteness. Of course, the extent to which an idea
invokes a concrete mental picture varies depending on the person.
Still, if I speak of waves in a pond,
most people will be
able to imagine what I mean, based on their own experiences. In
contrast, the only image (literally meant) that patriotic
duty
brings to my mind involves a tiny American flag.
Presumably if someone wants to explain why I should do something and
appeals to my patriotic duty,
they would rather not have me
think of a tiny American flag on a plastic stick with a little
Made in Taiwan
sticker on it. Patriotic duty is the stuff of
good propaganda, but not good explanation.