As I have been reading through comments to my last post on The Great Distraction, a scene passed through my mind that I thought (hope) would explain my point in a different light.
The point being that a low of time and energy is wasted when we discuss moral issues by a failure to respect the fact that changes in a definition does not make the same proposition both true (under one set of definitions) and false (under another). It creates two different propositions - and there is nothing at all wrong with one proposition being true while, at the same time, a different proposition is false even where both propositions use exactly the same symbols.
The scene is a beginning lecture for an Introduction to Chemistry class, where the teacher has just finished giving the opening lecture discussing atoms. A student in the class raises his hand and the teacher calls upon him.
STUDENT: Ms. Utley, you told us that atoms are made up of electrons, neutrons, and protons. Can you give me any reason why I should accept your definition of an atom, but not, for example, the ancient Greek definition? The ancient Greeks invented the term 'atom' and it literally means, 'without parts'. Why should I adopt your definition and not theirs?
TEACHER: Because science shows us that atoms are made up of electrons, neutrons, and protons.
STUDENT: That's only true under your definition of atom, Ms. Utley. If I accept the ancient Greek definition then it would be a contradition to say that atoms are made up of electrons, neutrons, and protons. It would be true by definition that atoms have no parts. So, if something were made up of parts such as electrons, neutrons, and protons then, by definition, it couldn't be an atom.
TEACHER: That's probably true. However, chemists don't define the word 'atom' that way any more.
STUDENT: (Laughing) I'm not an idiot, Ms. Utley. I know that. My point is that you can't give me an objective reason why I should use your definition and not the ancient Greek definition. It's all rather subjective, isn't it? It's just a matter of cultural preference whether we define 'atom' one way or another.
TEACHER: No. Science is objective. The Ancient Greek did not know that water molecules were made up themselves of atoms that had parts, but it was still true even if they didn't know it.
STUDENT: Again, Ms. Utley, that's only true if you take our definition of an atom. If we take the ancient Greek definition, atoms can't have parts. If these things you are talking about have parts then they can't be atoms. They have to be something else - something other than things without parts. Don't you agree, Ms. Utley? If these things have parts then calling them things without parts would be nonsense. You can't say that water molecules are made up of things without parts that have no parts.
TEACHER: Maybe. Let's move on.
The important point here is that, when discussing ethics, people treat the conversation above as a legitimate conversation with important points to make about the nature of morality.
In fact, all we have is a misunderstanding of the use of language.
It's true, in chemistry as in morality, that the definitions of words are subjective. If we choose to attach different meanings to our symbols than a set of symbols that would produce a true statement under one convention would produce a false statement under another.
But all that happens in changing our definitions is that we are changing the language that we are speaking. Translating a phrase from a language where the word "atom" means "the smallest unit of an element" into a language where the word means "smallest thing without any further parts" is no different from translating a phrase from English into ancient Greek.
The claim that this makes the same phrase true in one language and false in another is simply a mistake.
When we talk about the importance of different definitions it is simply false to claim that these different definitions make the same proposition TURE or FALSE depending on cultural or individual assumptions.
What we are talking about are two (or more) different propositions - some true, and some false - that just happen to be expressed using the same symbols.
For some reason, scientists tend to do a very good job keeping these two issues separate. They tend not to get entangled in the distinction between propositions and sentences.
However, when people discuss ethics, there are far too many people who seem to think that, when you change the meanings of words, you are not in fact changing the proposition. You are, in fact, making the same proposition both true (under one set of assumptions) and false (under a different set of assumptions) at the same time.
Not only is that a mistake, it contributes to a lot of time and energy being wasted in moral discussions.