In today's world, marketers reach inside the home and attempt to figure out not what's good for your daughter, because that is not their business, but what deep desires they can manipulate, stimulate and ostensibly satisfy in order to produce cold, hard cash.
A joke is not a thing but a process, a trick you play on the listener's mind. You start him off toward a plausible goal, and then by a sudden twist you land him nowhere at all or just where he didn't expect to go.
Of course, we have known for a long time that a word, like any verbal sign, is a unity of two components.

