(excerpted from Baker Encyclopedia of Christian Apologetics, Baker, 1999)

Like an old apple, relativism may look good on the surface but it is rotten at the core. Among its problems:

Most relativists really believe relativism is true for everybody, not just for them. But that is the one thing they cannot hold if they are really relativists. For a relative truth is just true for me but not necessarily for anyone else. So, the relativist who thinks relativism is true for everyone is an absolutist. Such a person believes in at least one absolute truth. The dilemma is this: a consistent relativist cannot say "It is an absolute truth for everyone that this truth is only relatively true." Nor can the person say, "It is only relatively true that relativism is true." If it is only relatively true, then relativism may be false for some or all others. Why then should I accept it as true? Either the claim that truth is relative is an absolute claim, which would falsify the relativist position, or it is an assertion that can never really be made, because every time you make it you have to add another "relatively." This begins an infinite regress that will never pay off in a real statement.

The only way the relativist can avoid the painful dilemma of relativism is to admit that there are at least some absolute truths. As noted, most relativists believe that relativism is absolutely true and that everyone should be a relativist. Therein lies the self-destructive nature of relativism. The relativist stands on the pinnacle of an absolute truth and wants to relativize everything else.

If relativism were true, then the world would be full of contradictory conditions. For if something is true for me but false for you, then opposite conditions exist. For if I say "There is milk in the refrigerator" and you say "there is not any milk in the refrigerator"—and we both are right, then there must be and not be milk in the refrigerator at the same time and in the same sense. But that is impossible. So, if truth were relative, then an impossible would be actual.

In the religious realm it would mean that Billy Graham is telling the truth when he says, "God exists," and Madalyn Murray O’Hare is also right when she claims, "God does not exist." But these two statements cannot both be true. If one is true, then the other is false. And since they exhaust the only possibilities, one of them must be true.

If truth is relative, then no one is ever wrong—even when they are. As long as something is true to me, then I’m right even when I’m wrong. The drawback is that I could never learn anything either, because learning is moving from a false belief to a true one—that is, from an absolutely false belief to an absolutely true one. The truth is that absolutes are inescapable.

Relativists have leveled several objections to the view of truth as absolute. The following are the most important:

It is objected that truth cannot be absolute since we do not have an absolute knowledge of truths. Even most absolutists admit that most things are known only in terms of degrees of probability. How, then, can all truth be absolute?

We can be absolutely sure of some things. I am absolutely sure that I exist. In fact, my existence is undeniable. For I would have to exist in order to make the statement, "I do not exist." I am also absolutely sure that I cannot exist and not exist at the same time. And that there are no square circles. And that 3+2=5.

There are many more things of which I am not absolutely certain. But even here the relativist is misguided in rejecting absolute truth simply because we lack absolute evidence that some things are true. The truth can be absolute no matter what our grounds for believing it. For example, if it is true that Sidney, Australia, is on the Pacific Ocean, then it is absolutely true no matter what my evidence or lack of evidence may be. An absolute truth is absolutely true in itself, no matter what evidence there is. Evidence, or the lack thereof, does not change a fact. And truth is what corresponds to the facts. The truth doesn’t change just because we learn something more about it.

Another objection is that many things are comparative—like relative sizes such as shorter and taller. As such they cannot be absolute truths, since they change depending on the object to which they relate. For example, some people are good compared to Hitler but evil as compared to Mother Teresa. Contrary to the claim of relativists, in-between things do not disprove absolutism. For the facts that "John is short in relation to an NBA (National Basketball Association) player," and "John is tall compared to a jockey" are absolutely true for all times and all people. John is in-between in size, and it depends on which one to whom he is compared whether he is shorter or taller. Nonetheless, it is absolutely true that John (being five feet ten inches) is short compared to most basketball players and tall compared to the majority of jockeys. The same thing is true of other in-between things, such as, warmer or colder, and better or worse.

If truth never changes, then there can’t be any new truth. This would mean that no progress is possible. But we do come to know new truths. That is what scientific discovery is all about. In response to this, "new truth" can be understood in two ways. It might mean "new to us," like a new discovery in science. But that is only a matter of us discovering an "old" truth. After all, the law of gravity was there long before Isaac Newton. Many truths have always been there, but we are just finding out about them. The other way we might understand "new truth" is that something new has come into existence that makes it possible to make a new statement about it that is only then true for the first time. That’s no problem either. When January 1, 2020, arrives, a new truth will be born. Until that day it will not be true to say, "This is January 1, 2020." But when that happens it will be true for all people and places forever more. So "old" truths don’t change and neither do "new" truths when they come to pass. Once it is true, it is always true—for everyone.

It is also objected that knowledge of truth is not absolute, since we grow in truth. What is true today may be false tomorrow. The progress of science is proof that truth is constantly changing. This objection fails to note that it is not the truth that is changing but our understanding of it. When science truly progresses, it does not move from an old truth to a new truth, but from error to truth. When Copernicus argued that the earth moves around the sun and not the reverse, truth did not change. What changed was the scientific understanding about what moves around what.

Of course truth is narrow. There is only one answer for what is 4+4. It is not 1. It is not 2,3,4,5,6,7,9,10 or any other number. It is 8 and only 8. That’s narrow, but it is correct.

Non-Christians often claim that Christians are narrow-minded, because they claim that Christianity is true and all non-Christian systems are false. However, the same is true of non-Christians who claim that what they view as truth is true, and all opposing beliefs are false. That is equally narrow. The fact of the matter is that if C (Christianity) is true, then it follows that all non-C is false. Likewise, if H (say, Humanism) is true, then all non-H is false. Both views are equally narrow. That’s the way truth is. Each truth claim excludes contradictory truth claims. Christianity is no more narrow than is any other set of beliefs, whether atheism, agnosticism, skepticism, or pantheism.

The claim that those who believe in absolute truth are dogmatic misses the point. If all truth is absolute—true for all people, times, and places—everyone who claims anything is true is "dogmatic." Even the relativist who claims relativism is true is dogmatic. For the person who claims that relativism is absolutely true is particularly dogmatic. This person claims to own the only absolute truth that can be uttered, namely, that everything else is relative.

Something important is overlooked in this charge of dogmatism. There is a big difference between the pejorative charge that belief in absolute truth is dogmatic and the manner in which someone may hold to this belief. No doubt the manner with which many absolutists have held to and conveyed their beliefs has been less than humble. However, no agnostic would consider it a telling argument against agnosticism that some agnostics communicate their beliefs in a dogmatic manner.

Nonetheless, there is an important distinction to keep in mind. Truth is absolute, but our grasp of it is not. Just because there is absolute truth does not mean that our understanding of it is absolute. This fact in itself should cause the absolutists to temper convictions with humility. For while truth is absolute, our understanding of absolute truth is not absolute. As finite creatures, we grow in our understanding of truth.

Truth may be tested in many ways but it should be understood in only one way. There is one reality, to which statements or ideas must conform in order to be regarded as true. There may be many different ways to defend different truth claims, but there is really only one proper way to define truth, namely, as correspondence. The confusion between the nature of truth and the verification of truth is at the heart of the rejection of a correspondence view of truth.

Likewise, there is a difference between what truth is and what truth does. Truth is correspondence, but truth has certain consequences. Truth itself should not be confused with its results or with its application. The failure to make this distinction leads to wrong views of the nature of truth. Truth is that which corresponds to reality or to the state of affairs it purports to describe. And falsehood is what does not correspond.