As I concluded Robert C. Greer's book, Mapping Postmodernism, I was struck by how much the "modernist"/"postmodernist" debate sounds like philosophical gibberish. Clothe it in whatever wording you choose, it is essentially the same argument philosophers have had since Plato and Aristotle. There is, as quoheleth says, "Nothing new under the sun."
Why would I say this? Well, quite frankly a major form of postmodernism is called antirealism. It states there is nothing real. Reality is what the mind makes it. Therefore, since all of us are different and see things differently there can be no absolutes whatsoever. Another form this takes is that while there may be something there after all, the human mind can only perceive some of what is. Therefore, perception becomes truth for you but it may not be for someone else. We are thrown back to relativism.
Modernists, we are told (and we're not talking about the Modernists of Classical Liberalism), are foundationalists and believe that something is and we can know it. Such knowledge may be imperfect and partial, but it can be studied, investigated, and the information derived is useful.
If I am not mistaken, and I am not a philosopher or even much of a theologian, Immanuel Kant distinguished between the noumenal and the phenomenal. The noumenal was the thing (ding an sich) and the phenomenal is what we perceived. There may well be an aluminum can, but we cannot know the actual can. We perceive the phenomena given off by the can. We can investigate the phenomena, experiment upon the thing and consider the changing phenomena, and test the phenomena until we can make use of the thing. Still, we cannot truly know the thing in and of itself.
Going farther back into history, the church was troubled by the debate over the nominal and the real. This was much the same argument but it preceded Kant by many years.
Plato's concepts focused on the real and the ideal. According to Plato, everything we see, touch, feel or experience in this world is but a poor copy of the actual object located in the ideal realm. Plato illustrated his ideas in his classic on "the cave."
It is the same old argument floating around. Today's version is subtly nuanced in order to fit a world where coping has become increasingly difficult due to the interaction of various cultures and worldviews. So many have come across as always right having truth sewn up and neatly packaged. Those who think they have it all often act in unloving, judgmental, and condemning ways rejecting anyone who disagrees with them. Legalistic, toxic churches have done more damage to the truth of biblical Christianity than one can imagine. Rather than offering loving acceptance followed by patient and persuasive teaching, too many Christians expect total agreement with every assertion.
It is no wonder that so many heathens (and I use that word in a non-pejorative sense) reject the faith. Their honest questions and doubts were rejected out of hand and they were told to "measure up" without giving them an opportunity to seek out the truth. That must change before the church will get much of a hearing.