Wikipedia: Meta-ethics

Meta-ethics is the study of what sort of meaning ethical sentences have. That way of putting it is a little misleading, so let me clarify. Here's an ethical sentence: "Pleasure is good." If I tell you, "Meta-ethics studies what sort of meaning ethical sentences have," then you might think to yourself, "I guess he means that meta-ethics studies what I mean by good when I say that pleasure is good."

Well, that's really not quite right. That question, about what "good" means, would be better regarded as a topic under the theory of value. That's really just my opinion; other philosophers, like Hospers in our reading, would say that the meaning of the word "good" is definitely a topic in meta-ethics, not the theory of value. They would say that the theory of value investigates which sorts of things are good, once the meaning of "good" is explained. But as far as I'm concerned, we may as well consider these two questions, about what "good" means and about which things, in general, are good, as being at bottom the same. And they are both questions answered in the theory of value. But in that case, if meta-ethics isn't in the business of defining "good," then how is it concerned with the meaning of ethical sentences at all? How are we to understand this claim that meta-ethics is the study of what sort of meaning ethical sentences have?

The emphasis is on the words what sort. In other words: meta-ethics asks which of various kinds of meanings ethical sentences might have. But now your natural question is going to be: "What do you mean various kinds of meaning of ethical sentences? What kinds of meaning do you have in mind? What are my choices?"

Well, let me explain your choices, using our sentence about Mary as an example. After presenting all three, I'll explain each choice in more depth.

(1) The meaning of "Mary is a good person" can be explained using another sentence that does not use the word "good." For example: "Mary, on the whole, has made people in the world happier than they would have been without her." Or: "Mary has a number of habits like telling the truth, discharging her responsibilities regularly, being nice to people, and so on."

(2) The meaning of "Mary is a good person" cannot be explained using another sentence, because, although the sentence does express a proposition, the word "good" is primitive, which means that its meaning cannot be stated in other words at all.

(3) The meaning of "Mary is a good person" cannot be explained using another sentence, because this sentence merely expresses or evokes a certain kind of emotional reaction, or involves a certain kind of command or recommendation. It's as though we were saying "Yay for Mary!" Or: "Look at Mary! Be like her!" But in any case, this third option denies that "Mary is a good person" expresses a proposition. All it does is express an attitude or a feeling.

Now remember, what I'm trying to do is to explain to you what meta-ethics is. I said it is the study of what sort of meaning ethical sentences have; but now we can say something much more specific, because now we have some rough idea of three options that we?re talking about when we talk about "sorts of meaning." Here's how we could put the central question of meta-ethics; it's a three-part question. "(1) Can the meaning of ethical sentences be restated in other words that do not use normative concepts like good and right? (2) Do ethical sentences express propositions? (3) Can the meaning of ethical sentences be explained entirely in terms of the emotions they express, or are meant to cause in other people, or in some other way that doesn't involve expressing a proposition?" The different meta-ethical theories differ just in how they answer each of these questions.

I'll admit that this is rather complicated, so I don't expect you to understand it fully yet. Let's go over the different main meta-ethical theories. I think once we've gone over the different theories, you'll have a better idea of of what these three questions mean. So let's dive right into the first main meta-ethical theory.

See: