For the purposes of this post, I'm using the Merriam-Webster definition of post-modern "of, relating to, or being a theory that involves a radical reappraisal of modern assumptions about culture, identity, history or language."
First, I want to say that there is truly nothing new under the sun. We seem to think that we are the only "post-modern" society, when anyone who has actually studied theology, philosophy or history, knows the cyclical nature of the world we live in.
Second, I want to point out a few fallacies of a post-modern theology or moral stand.
For the first part, if you are familiar with your Bible, you may associate "nothing new under the sun" with Ecclesiastes. If you have read Ecclesiastes or Job, you will see several examples of "post-modern" thinking from approximately 950 years before Christ.
Nearly all of the great philosophers challenged current thinking, and asked critical questions about life, culture, and theology. So, to say that a new way of thinking is unique to only this generation, is a little naive.
Now, let's look at some fallacies in what is considered to be "post modern" theology and morals.
First, there is the idea that if the general populace agrees on a new moral, then it shall be. This is not only a moral fallacy, but a "post modern" conundrum. If what we are doing is radically reappraising modern assumptions, then why would the cultural plurality be the answer?
If we are doing away with every moral compass and just going off of each individual persons moral compass, then how can you judge anyone for breaking a law or doing something you feel is wrong (it is, after all, just your opinion)?
I find that many post-modern people believe two things about theology: that the Biblical standard for right and wrong is irrelevant, and that bad people deserve to get punished and "good" people do not.
First, if the Biblical standard for right and wrong is irrelevant, then why should you personally get to determine who gets punished and who doesn't? What is your standard? Every law and morality in the universe is based, to at least some degree, on the moral standard of the Bible. Are you really greater than those who come before you? If you think so, definitely read Ecclesiastes, you need to hear it.
Second, if bad people deserve to get punished then on what moral standard should they be punished? Should they only be punished if it's something that's personal to you? Should they only be punished if they hurt someone physically? Should they only be punished if they hurt someone who can't hurt them back? To what degree have they done wrong and who determines that degree? The government? The populace? Courts and judges? The media?
The painful beauty of truth is that we have all sinned. My sincere hatred of another person is just as hurtful to society, myself, and God, as the physical murder of a man. We can attempt to justify all we want to that our good outweighs our bad, but who is to determine that? The scales of justice truly are blind, in that God cannot look upon sin, of any kind.
The sad truth of our "Me society" and the "Facebook generation" is that we feel that our own viewpoint must be true because we can be friends with other people who feel the same way we do. In all honesty, if we started a petition to have people who don't have children be allowed to count their dogs as dependents, we could probably get it to pass in Congress. Society is no longer based on standards, but rather based on opinions. The dangers of not thinking for yourself can seem humorous, but they are all too real.
To truly live in a "post-modern" society (whether 950 BC or 2015), we need to be able to think critically and have an answer for the faith to which we've been called. My faith is not groundless. My faith is not tradition. I know who God is because I have seen His power at work in my life and in the lives of those around me. God is not someone to be feared or a religion to be hated. Jesus was not a good man or a great prophet. Christianity was never designed to sit within the four walls of a church one morning out of the week. I walk in the way that I was taught, not because I was taught it, but because it has been proven true.
Ask critical questions. Ask where your own moral standards come from. Learn what others are thinking without letting it dilute the truth. Let's live in a post-modern society and become the post-post-modernists. Or would that be the post-modern modernists? Here is the biggest critical question to ask when you are evaluating your own heart and beliefs: If you claim to be a Christian, are you simultaneously trying to claim that your viewpoint is greater than His?
I'm not a big history buff if you ask me about dates or names or battles. But I can tell you that history comes in cycles, and I pray and hope that we are due for another Great Awakening soon.