No one means all he says, and yet very few say all they mean, for words are slippery and thought is viscous.

Adams is pointing to a double mismatch between language and intention. On one side, speech routinely exceeds what a speaker strictly intends (“no one means all he says”): words carry connotations, implications, and social effects beyond conscious control. On the other, speakers also withhold or cannot fully articulate their inner meaning (“few say all they mean”), whether from prudence, self-deception, or the limits of expression. The metaphor sharpens the diagnosis: words are “slippery,” tending to slide away from precise reference, while thought is “viscous,” dense and resistant to being poured cleanly into sentences. The result is chronic misunderstanding and the need for interpretive charity.