Relativism is such a dark and tangled mess of a doctrine that it can hardly be stated without destroying itself, or seeming to change into something else.

It might be defined as the view that nothing is true absolutely--that all truth is true only “for someone.” But if, as seems right, truth by its very nature is true absolutely (true for everyone, and for all time) then to be a relativist, it seems, is to deny that there is any truth at all: and then relativism changes into something else, nihilism.

Also, does the relativist wish to say that relativism itself is true only relatively? I mean, when he asserts, “All truth is true only for someone,” is that assertion true only for him? If so, then he can’t say that anyone else ought to agree with his relativism. But if not, then he contradicts himself, because he thinks that at least one truth is true absolutely.

It’s puzzling, too, how anyone could even understand relativism, unless it were false. The reason is that typically the qualified use of a word presupposes its unqualified use. For instance, I cannot understand the phrase “my cup,” unless I first understand what “cup” means, just on its own. I cannot understand “next to me,” unless I already understand what it is for me to have a location. So how would it even be possible to understand the phrase “true for you,” unless we understood already what “true” just on its own meant? And yet how could we understand that, unless we had learned it, and how could we have learned it, if nothing were really like that?

No one is a relativist across the board. I’ve never heard of anyone who is a relativist about mathematics (“Don’t impose your arithmetic on me!”) or physics (“It’s only true for you that this nuclear bomb can incinerate a city!”).

Furthermore, no one is a thoroughgoing relativist even in all matters of morality. I don’t mean merely that relativists will contradict themselves as freely as did those Parisian students of ‘68 who sloganized, “Il est interdit d’interdire” (“It is forbidden to forbid!”). I mean also, for instance, that the most committed relativist in sexual morality will nonetheless still insist that, within sexual morality, rape and pedophilia are just plain wrong.

So I conclude that relativism is false, incoherent, and impracticable. More than that: it is obviously so. This then raises the interesting question of why anyone accepts it.

Most people adopt relativism in personal relationships because it seems friendly. To disagree with someone is, well, disagreeable. You butt your opinion and your will against his: someone has to give way, and, if you stick to your view, it won’t be you. How much easier, then, to avoid conflict, split the difference, and say that what he believes is true for him, and what you think is true for you!

But this is a spurious transaction, because each party to the deal ends up just where he started. They leave the discussion as two isolated egos floating past each other; each is left unperturbed, but at the price of inhabiting a world that is true only “for him.”

Relativism as practiced like that in personal relationships is actually flattery rather than friendliness, because each person is concerned to tell the other what he would like to hear, not what is good (but perhaps unpleasant) for him to hear.

True charity would imply that each person approach a conversation actually desirous of being resisted and contradicted by the other, when he happened to say something that appeared wrong. Only in that way can a conversation foster a real exchange of truth and a genuine meeting of minds.

This personal attitude of relativism--a kind of flattery--expresses itself in politics also, but only sporadically, because no one can practice it consistently, and because it really is the eruption into the public square of an essentially personal attitude. For instance, a desire simply to “go along,” and not resist what others think, seems to be the main sentiment behind sympathy for the cause of same-sex marriage.

Another cause of relativism is the rejection of legitimate, relevant authority--by those who need authority.

In reality, all knowledge first begins by one’s seriously grappling with conflicting and incompatible views, each of which has a strong claim to truth. All science and all scholarship proceeds in this way. The conflict eventually gets decided by experts, who then write the textbooks, which most of us accept. (Those who don’t accept the textbooks are “poor students.”) That is, most of us accept science on the basis of scientific authorities.

And that is how we ought to proceed, because, as we are not experts, we would be incapable of making sound decisions about which theory is right, if all of the arguments for the opposing theories were presented to us in their full power, by advocates of those theories.

If it were common to reject scientific authorities, as authorities in ethics are rejected--to reject them persistently in a system of education, and from an early age--then relativism about science, too, would be common, because most people would be at a loss to decide which theories were true; and when they saw that everyone else was at a loss, like themselves, they would conclude that what they believe is at best merely “true for them.”

Michael Pakaluk is Professor of Philosophy at the Institute for the Psychological Sciences in Arlington, VA.