Whereas conservative evangelicals have staked their all on the existence of propositions, the fact of the matter is that human language is not grounded in abstract, non-linguistic, ghostly entities that exist only in the mind of god. Rather, human language is grounded in human social conventions and social practices. This scares conservative evangelicals, because they would like to appeal to something stable, fixed, unchanging and eternal, whereas social conventions and practices are imprecise and constantly changing. But conventions and practices do not need to be perfect, they just need to be stable enough to get the job done, and they are in fact that. We use language to accomplish specific goals, and our social conventions need only be good enough to assist us in our goal-oriented behavior.
For those willing to step into more than "pop" philosophy and theology, Steve has a lot of other good things to say on his blog.