It seems that an awful lot of needless confusion and pointless arguments could be avoided if people would bear in mind the difference between a superficial word-symbol and the concept which it refers to.
I came across a really good example of this in a philosophy book I was glancing through a few weeks ago. They pointed out that the age-old question of "Does a tree falling in an empty forest make a sound?", hotly debated for several millenia, was nothing more than an empty semantic quibble. The answer merely depends on what you mean by the word "sound". If you are using the word to refer to the concept of physical sound-waves, then the answer to the riddle is a simple "Yes". Alternatively, if by "sound" you intend to refer to the subjective conscious experience of an agent 'hearing' something, then the answer is just as obviously "No".
There is no deep mystery here. Just pointless muddle and confusion arising from a lack of distinction between words and their meanings (reference), which can all too easily lead to unconscious equivocation between two quite different concepts.
I think that this problem is particularly prevalent when people start to talk about ethics / moral philosophy. All too often I hear people arguing that morality must be subjective, because different people (or cultures) follow different moral principles (i.e. have different moral beliefs) as a matter of fact.
But what is meant by the word "morality" in this context? There are (at least) 2 distinct possibilities, and it is crucially important to distinguish between them. Firstly, there is what I call sociological morality, which merely refers to whatever general code of conduct a person or group adheres to. In this sense, it is trivial to observe that morality is 'subjective'. All this statement says is that different people behave differently from each other, and have different beliefs. Well, duh.
It is the second broad definition of "morality" that we are interested in... the type I call philosophical morality: what general code of conduct we OUGHT to adhere to. In this sense, the fact that different people have different moral beliefs is quite beside the point (after all, the same can be said for scientific beliefs) - our beliefs do not affect the truth of the matter (whatever it may be). It may simply be the case that some (or most, or all) of us are mistaken in our beliefs.
So this "argument from relativity" does not actually show (philosophical) morality to be subjective or relative at all. The argument is fallacious, resting on a equivocation between two different meanings of a single word-symbol. If used consistently, it is found that the conclusions drawn are either trivial, or false.
However, the argument from relativity does actually demonstrate one genuinely useful fact: that IF "moral facts" or "objective values" exist, they are at least not immediately observable or evident to human beings. The controversy over morality makes that much clear.
So that demonstrates one linguistic cause for confusion in moral debate. But that's not all. People often suggest various alternative definitions for "morality", and then argue that because we cannot 'prove' that they're wrong, morality must be subjective (or at least unknowable).
For example, Bob might decide to define "moral" as meaning "whatever will fulfill Bob's desires". Now, if Bob happens to enjoy murdering or raping people, then it seems that murder and rape are (according to this definition) "moral", and there's no way we can 'disprove' this. Well, that's true enough. True, but utterly inconsequential. The problem is that Bob is using the word-symbol "moral" to refer to a totally different concept from what the rest of us are talking about. Bob could just as easily redefine "elephant" to mean "fish", and then argue that "elephants live in the ocean" is a true statement.
So this silly wordplay, this redefining of words to refer to entirely different concepts from what the rest of us are using a word for... well, it's really not a very meaningful exercise.
One final observation: there is a way for Bob to avoid this criticism. Instead of stipulating a new definition and arguing from there, he may instead uphold an ambiguous but generally-accepted old definition (eg morality = "what people OUGHT to do"), and posit his definition as being the true meaning of the old phrase. That is, he might argue that "what people OUGHT to do" = "whatever will fulfill Bob's desires".
This strategy certainly seems a lot harder to dismiss. After all, how can we prove one way or the other what we 'ought' to do? What does 'ought' even MEAN, anyway? Actually, that last question is the one I consider to be at the very heart of the issue, and it is that which I will tackle in my next post.