The postmodernists philosophical view is summed up in the term anti-realism. The basis of postmodern philosophy is that truth cannot be known, facts cannot be known, "reality" does not exist. Nietzsche, the great postmodern philosopher who decreed the death of God, says, "There are no facts, only interpretations." What we see is not reality, but simply our own perception of reality. We all (I hope) would say that the sky is blue, but this is not an objective truth, we simply all happen to have the same perception of reality. Conversely, if you were to walk through an insane asylum you might encounter people who think they are anything, from glass to God. Just because you know yourself to be a human being does not mean that you are sane and they are not, they just perceive reality differently than you do. Who are you to say that they are not "in touch with reality"? Maybe you are the one out of touch with reality, or perhaps reality itself is a figment of your overactive imagination.
This is exactly where postmodern philosophy logically concludes. But can man truly live as though there is no objective truth? One may say they do not believe in objective truth, but every day they live as though there was. They live in their house as though it were real. They drive to various places in their cars as though those places existed in reality and not just in their mind. They love their children, and care for them, and feed them, as though they were living, breathing human beings. They pay their taxes, because they are aware that there will be consequences if they do not. One cannot truly live as though objective truth does not exist, they just can't do it.
Even Friedrich Nietzsche lived and talked as though objective truth existed. Over and over he talks about escaping the truth, and he defines faith as "not wanting to know what the truth is." Once he said something that painfully revealed how close, and yet how far he was from finding an objective truth by which he could consistently and faithfully live his life.
He said, "In truth, there was only one Christian, and he died on the cross." Yes, Mr. Nietzsche, you are right, for once. There was only one man who could truly be labeled a Christian. His name was Christ, and it is His character that all Christians today seek to exemplify. Unfortunately, though, we fail miserably. Why? Because the man Christ was God in the flesh. The God you claim is dead came to earth in order to show us what a perfect, holy, and righteous life looks like. He knew we would never be able to live like He did, so He offered Himself up to be killed, on a cross, just as you said. His perfect blood covers our shortcomings, and allows us to be seen as righteous in God's eyes.
There is one important thing that you forgot, though. Christ did not remain dead. If He had, your most famous declaration would be sadly, tragically true. But no, for on the third day Christ rose from His grave in triumph over death, so that we here today can have victory over our failures.
Nietzsche pinpointed part of the truth, but he didn't search for the final piece. He didn't grab hold of the one objective Truth that makes sense of the whole world. The Truth that God is not dead, and that He rules over this world and offers us salvation through Jesus Christ is the Truth that allows us to believe that reality can and does exist. It allows us to believe that the sky is blue, that eating food and drinking water will sustain our bodies, that the world is an actual spacial and geographical reality. Most importantly, it allows us to believe that Heaven and Hell are real, and that our belief in that ultimate Truth and our subsequent action upon it will determine where we spend a very real eternity.