[teddyh]

In what theoretical dimension do you find these “neutral interested third party” people? In my experience, every discussion is a result of (at least) two people with both an opposing view and and, more crucially, an interest to argue the point. The very prerequisite of a debate is an interest in arguing a specific point of view, which most often precludes any participant being a neutral third party.

Of course, you could always argue “for the gallery”, i.e. not try to persuade your opponent, but to merely use the debate as a platform to reach an audience. But this is not persuasion; this is rhetoric. Analogies can be used as rhetorical tools. But analogies won’t persuade your opponent.

Therefore, if you’re arguing with someone else one-on-one, and there is no one else to win over by rhetorical tricks, you should avoid using analogies, since analogies aren’t persuasive.