When it came to matters like hunting, some important knowledge could be transmitted using words—like where one might find some diamphidia larvae to poison an arrowhead, or which animal sinews made the best bowstrings. But the most important forms of knowledge could not. This kind of knowledge, they insisted, could not be taught because it resided not just in their minds but also in their bodies, and because it found expression in skills that could never be reduced to mere words.

Mission statements, synergies, strategies, visions—they are often ambiguous to the point of being meaningless. Naturally sticky ideas are full of concrete images —ice-filled bathtubs, apples with razors—because our brains are wired to remember concrete data. In proverbs, abstract truths are often encoded in concrete language: “A bird in hand is worth two in the bush.

Simple messages are core and compact.

At one level, the idea of compactness is uncontroversial. Rarely will you get advice to make your communications lengthy and convoluted, unless you write interest-rate disclosures for a credit card company. We know that sentences are better than paragraphs. Two bullet points are better than five. Easy words are better than hard words. It’s a bandwidth issue: The more we reduce the amount of information in an idea, the stickier it will be.

But let’s be clear: Compactness alone isn’t enough. We could latch on to a compact message that isn’t core; in other words, a pithy slogan that doesn’t reflect our Commander’s Intent. Compact messages may be sticky, but that says nothing about their worth. We can imagine compact messages that are lies (“The earth is flat”), compact messages that are irrelevant (“Goats like sprouts”), and compact messages that are ill-advised (“Never let a day pass without a shoe purchase”).

Generative metaphors and proverbs both derive their power from a clever substitution: They substitute something easy to think about for something difficult.

Nineteen centuries ago, the Greek Stoic philosopher Epictetus said, “Nature hath given men one tongue but two ears, that we may hear from others twice as much as we speak.” Unfortunately, not many people listened to him.