I had an interesting exchange recently on a forum with a gentleman who insisted that there is no such thing as "absolute truth". All truth is relative, he said, depending on the concensus of the time. 100 years ago racism was acceptable; today it is not.
I asked him to clarify whether he really meant that racism was morally right then, or simply that a majority believed it was. Surely, I said, you do not really believe that racism ever was good. Rather, what you mean must be that a majority believed it to be good, but they were wrong.
No, he replied, truth is relative. He then gave a second example: Thousands of years ago people believe that the world was flat, so it was flat. Today we believe that it is round, so it is round.
My last round in the conversation was to say that we have so little common ground that it is difficult to see how we could even discuss this question. I could point out that his position leads to logical inconsistencies. Like, suppose a flat-earther and a round-earther set out on a journey together travelling in a straight line. They hold hands the entire way. Eventually the round-earther must come back to his starting point. But the flat-earther must continue getting farther and farther from his starting point. So at some point, even though they are holding hands, do the two separate? What happens when they have travelled a sufficient distance to go around the world?
But I suppose he would reply that this argument is meaningless. As truth is relative, each person has his own truth, and so contradictions are unimportant. Indeed, my whole goal in such a discussion would be to demonstrate that his theory is false. But he doesn't believe there is such a thing as "false". To him the word "false" is just a sound with no meaning, like saying "foobar". How can I logically prove that things can be proven logically? How can I make a scientific argument to demonstrate that scientific arguments have the power to demonstrate anything?
We just have no common ground.
Which got me to thinking: In any discussion or debate, you must start with some common ground or the conversation will go nowhere.
Consider theological arguments. I am a Fundamentalist Christian. When I discuss theological questions with other Fundamentalist Christians, we are both starting with a belief in the Bible. So any such debate tends to center around, What Bible verses can you point out that support your position? Of course sometimes we disagree about the interpretation or implication of some Bible verse. For example, one person might say that a command given in the Bible applied just to the group of people specifically addressed in that particular place at that particular time, while the other person says that it applies to everyone throughout history. But then we can turn to other Bible verses that might clarify the meaning. We might use historical or scientific evidence. As Fundamentalists, we believe that God created an orderly, comprehensible universe, so we can look to the world around us to gain understanding. (In Christian theology, the Bible is sometimes called "special revelation" while science is called "general revelation".) And of course we will both use logic and deduction, because we believe that God has created us with minds that can be in tune with reality.
The group that I find next most productive to discuss theology with are atheists. Perhaps you find this statement surprising. You might think the next most amenable group to me would be people who perhaps don't take the Bible literally, but accept it as a moral authority, i.e. liberal Christians.
But I find this is not so. Most atheists, at least those I've talked to, think of themselves as scientifically-minded people searching for truth. This is something I can readily relate to. Both the atheist and the Fundamentalist believe that there is such a thing as objective truth, and that that truth can, at least in principle, be discovered by studying the world around us. Of course we have come to very different conclusions, but our methods and our goals are at heart the same.
Of course sometimes Christians and atheists have unproductive conversations. Sometimes a Christian will try to convince an atheist by declaring, "The Bible says so." Of course the atheist is unimpressed, because he is not convinced that the Bible is authoritative. Likewise, sometimes an atheist will try to convince Christians by declaring, "All scientists agree this is so." Of course the Christian is unimpressed, because even if it is literally true that all scientists say this -- which of course it almost never is -- the Christian is not convinced that a vote by a group of fallible humans is authoritative. (Especially when it contradicts what we believe to be the word of God. How many humans does it take to out-vote God?)
But when the Fundamentalist and the atheist start discussing actual evidence -- scientific, historical, whatever -- we may not agree, but at least we can and do debate rationally. We both believe that there is a truth to be discovered, and that scientific experiments and historical research are valid ways to find that truth. We will question the accuracy of the facts the other cites or challenge the logic that he uses to draw his conclusions, but we agree that facts exist and logic is valid.
When I talk to a liberal Christian, on the other hand, I find the supposed common ground far too slippery. He will say that he believes something based on such-and-such a Bible verse. I challenge his understanding or application of this Bible verse by pointing to another that I believe clarifies or illustrates the true meaning of the first. But then he replies by saying that he doesn't believe the verse I just quoted or doesn't think it's important. I try to point out something about the historical context in which the Bible was written or technicalities in the language, and the liberal Christian dismisses this as irrelevant because he is concerned with the "deeper truth" rather than these details. I am left floundering. You believe the parts of the Bible that can be read to support conclusions you like, but dismiss those that contradict your conclusions? Then why use the Bible at all? Aren't you just stating your own opinions with nothing to back them up except other opinions of yours? I've had many discussions like this that go nowhere because we have the illusion of common ground, but no reality. I'm not sure if the liberal Christian thinks that his philosophy makes perfect sense in some way that he has never managed to explain to me, or if he just doesn't care that it is inconsistent. I'm sure the liberal walks away from the conversation equally frustrated at our inability to communicate, but I am baffled as to what he is actuallly thinking. I wonder if he leaves thinking, "Wow, this guy just can't get past worrying about antiquated concepts like 'facts' and 'truth' and move on to a deeper spiritual understanding." Or ... what?
And when I try to talk to relativists like the gentleman I discussed at the beginning of this article, I just don't know how to even begin a rational conversation. We have no common ground at all. If you don't even believe that there is such a thing as truth, how can you discuss whether something is true or false. Indeed, as others have pointed out, if someone says that there is no such thing as truth, we are left to wonder, Does he believe that that statement is true?
What particularly baffles me is that the person I had this conversation with was a technician working on genetic research -- maybe you'd even call him a scientist. If he believes that truth is just the popular concensus of the moment, why does he bother to participate in scientific research? If we take a vote and everyone agrees that the world is flat, and that means that it is flat, then why should we do scientific research to investigate the shape? That would just be a waste of time when we already know the truth. Indeed, scientific research is often expensive, requiring years of work by highly skilled people and lots of expensive equipment. Why bother when we can find the truth just by consulting the latest Gallup poll? And wouldn't any experiment have to confirm what the majority already agreed was true? Or if it doesn't, if experiments indicate that the world is round, and then the scientist goes around telling everyone that the world is round ... isn't he spreading a lie? You've just told me that if the majority believe the world is flat, then that makes it flat. So if you say it's round, you must be mistaken or lying, right? But if you keep up this lie long enough and eventually convince 51% of the people to believe this lie, then suddenly the lie becomes the truth, and the old truth becomes a lie. Or something like that. It leaves my head spinning to comprehend such a philosophy.