The human condition tells us our own experiences, the experiences of others, logic, and our heart cannot always tell us what is true. The human condition tells us our culture has a major impact on what we believe and how we think. Given that our existence has been structured in this fashion, how do we know what to believe? Does this mean that knowing truth is impossible? Do we cease to believe that truth exists? Many in today’s world take this approach. Postmodern theory say there is no objective truth. What we call truth is just a special kind of story for a particular culture. Different cultures view the world very differently so none of them can claim to have knowledge of the truth. The attractiveness of postmodernism is that it contains an element of truth. Knowing what is true is difficult as we have seen in the past few blogs. But there are contrary facts that cause us to believe objective truth does exist.
We can know objective truth exists for three reasons. First, our physical world provides us with ample evidence. E. H. Carr observes that just because a mountain appears to be shaped differently from different angles does not mean the mountain has no shape or infinite shapes.  It can be determined from the various viewing angles the particular shape the mountain has. Also, if anyone thinks the law of gravity is not an objective reality and jumps off the top of a tall building, do we expect that they will not experience bodily harm or death? There is no debating with the law of gravity. We can mitigate its effects as when we use a parachute when we jump from an airplane but if the law of gravity was not an objective reality we would have no need of parachutes. The technology of our civilization is a result of scientists and engineers determining what knowledge accurately reflects the real world and what does not. This is another way of saying that they are distinguishing between knowledge that is true and knowledge that is false. Do engineers design buildings, cars, airplanes, or power plants without regard to the laws of science and engineering? If they did, the results could be disastrous and would most likely invite criminal prosecution. Our technology must constantly deal with the reality (truth) of our world. As Patrick Grim states: “If there is no truth, there is no knowledge. 
Second, we are able to communicate with other cultures and past civilizations communicate to us via their writings and artifacts. While different cultures have very different world views, there are areas of common knowledge. We are all human and we all have certain capabilities and limitations. The human condition does not change drastically between cultures and ages. These provide a reality (truth) that all people share. Postmodernism wants to emphasize our differences but it must be recognized that humans share much regardless of the different cultures and ages in which we live.
Third, Popper notes that all admit we are fallible but being fallible implies a standard of objective truth.  Trueblood makes the observation that error is an unassailable fact of the human condition but if error exists then truth must exist as well.
It is no idle paradox to point out that we are more sure of error than of anything else, since we imply it even by denying it. Either there is error or there is not. But if there is not, then those specific persons who have believed that there is have, themselves, been in error. It is really easier to be sure of falsehood than of truth, yet if there is falsehood there must be truth, for what can falsehood deviate from, if not the truth. 
Anyone who would assert that error does not exist would be considered a fool. So why is there any debate about truth? David Berlinski asks: Is the statement “there are no absolute truths” an absolute truth? If it is, then some truths are absolute after all. 
 Richard J. Evans, In Defense of History (New York: W. W. Norton & Company, 1999), p. 193.
 Patrick Grim, Questions of Value (Chantilly, VA: The Teaching Company, 2005), p. 127.
 Karl Popper, Conjectures and Refutations (London: Routledge Classics, 2002), p. 21.
 David Elton Trueblood, Philosophy of Religion (New York: Harper & Row, 1957), p. 45.
 David Berlinski, The Devil’s Delusion (New York: Crown Forum, 2008), p. 129.