Absolute Truth, Again

I keep looking for ways to explain absolute truth. See, if you can't convince someone that there is such a thing as Absolute Truth, then everything is relative and there's no way to have an argument. Here I mean argument in a philosophical sense. According to The Internet Encyclopedia of Philosophy: "In philosophy, “arguments” are those statements a person makes in the attempt to convince someone of something, or present reasons for accepting a given conclusion." It doesn't mean quarrel. As G.K. Chesterton said: "Never let a quarrel get in the way of a good argument."