A.J. Ayer, a twentieth century British philosopher, was a major proponent of logical positivism. This movement saw empirical science as our main source of knowledge and was skeptical of traditional philosophy.Logical Positivism
Ayer applied logical positivism to ethics and came out with a view called emotivism -- that ethical judgments are emotive utterances and not truth claims. This raised a big controversy; philosophers are still arguing about the view.
These summaries and problems deal with parts of Ayer's Language, Truth and Logic. These materials are copyrighted (c) 1998 by Harry J. Gensler but may be distributed freely.
The logical positivists thought that philosophers often debated nonsensical issues. They proposed this principle -- the "verifiability criterion of meaning" -- to test if a claim is cognitively meaningful (in the sense of being true or false):Emotivism
A claim is cognitively meaningful if and only if it's either ANALYTIC (true because of logical connections and the meaning of the terms) or EMPIRICALLY VERIFIABLE (some conceivable set of experiences could test whether it was true or false).
The positivists thought that "God exists," for example, fails the test since it's neither analytic nor empirically verifiable. So they thought that "God exists" isn't true or false; it lacks cognitive meaning and has only emotive meaning. So they called "God" a pseudo-concept.
Ayer's logical positivism implies that moral judgments are cognitively meaningful if and only if they are either ANALYTIC or EMPIRICALLY VERIFIABLE.Reason in Ethics
Ayer was sure that moral judgments aren't analytic. And he thought that G.E. Moore refuted naturalism; and so moral judgments aren't empirical. It follows that moral judgments aren't cognitively meaningful; they only have emotive meaning.
"X is good" was seen as an exclamation (like "Hurrah for X!"). "X is good" isn't true or false, and so can't be known to be true. Ethical truths and ethical knowledge are impossible.
We can reason on ethical issues if we assume a system of values. We can then appeal to the empirical facts to show that, given this system of values and these empirical facts, such and such a moral conclusion follows. With people who share a similar system of values, such reasoning can be fruitful.
There's no way to REASON about a pure question of value (a basic moral principle). It's possible to use EMOTIONAL means at this point -- but not reason.
Emotivism is a form of noncognitivism -- the view that there are no moral truths.