There are a number of ways I could employ my own right now, but I'll restrain myself.

Let me just say two things. First of all, it is perfectly possible to convince someone else through debate. It has personally happened to me several times (as both the convincer and the convincee). And it doesn't necessarily take any kind of high opinion of oneself, only of one's arguments.

Second, if you only interact with people whose values match your own, you'll live a pretty lonely life. And yeah, I know that's not what you said, but it's really only a hop, skip, and jump away.