If I were to say that Elbonians and rats have something in common – specifically their love of cheese, would that be seen as an insult to Elbonians?
Answer: Yes. While the point of the analogy is extraordinarily clear, and limited to a love of cheese, most people would wonder why I chose rats for the comparison when mice would have worked just as well. Mice are not nearly as insulting as rats.
Suppose you didn’t know that I had contemplated using rats in my analogy. Instead, all you heard me say is that Elbonians and mice have something in common – specifically their love of cheese. Would that be seen as an insult to Elbonians?
Answer: Yes. No one wants to be like a mouse, even in a way that happens to be true for just about all mammals. Who doesn’t like cheese?
Analogies are fighting words. When I was younger and dumber I often used analogies to try and make my point. This strategy worked exactly zero times. When people hear analogies, it flips a switch in their brains that turns on the crazy. Even the simplest analogies fail when you use them in an attempt to persuade. And they fail every time.
With that said, there are two proper times to use analogies. One way is in the service of humor. Humor is all about activating the crazy part of the brain. If I say I witnessed more horrible things than Charlie Sheen’s cat, your brain leaves your logical mode behind. The analogy sets you free.
The second proper time to use analogies is when you want to cause trouble. You should not try this at home. Leave it to the professionals. For example, when you hear Glen Beck or Rush Limbaugh getting a lot of heat for something they said, often there is an objectionable analogy at the heart of it. The most famous example is Limbaugh’s coining of the word feminazi. If your job involves making people talk about you, analogies can be powerful tools.
[Update: As if on cue, a serious debate turns into a discussion of the appropriateness of the analogy instead. And notice how well analogies work in the service of humor in this example.]