Ayer's logical positivism left no room for objective accounts of ethics or theology. "X is good" and "There is a God" both fail Ayer's meaningfulness criterion; hence neither statement makes a genuine truth claim.Emotivism
These summaries and problems deal with Chapter 6 of Ayer's Language, Truth and Logic. These materials are copyrighted (c) 1998 by Harry J. Gensler but may be distributed freely.
Ayer's logical positivism says "All truth claims are either empirical or analytic." Ayer was convinced that moral judgments were neither empirical nor analytic. He concluded that moral judgments weren't truth claims.Reason in Ethics
Ayer further reasoned that moral judgments, since they aren't truth claims, must be expressions of feeling. "X is good" functions as an exclamation -- like "Hurrah for X!" So moral judgments simply express feelings; there cannot be moral truths or moral knowledge.
Thus logical positivism led Ayer to emotivism.
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.Theology
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.
Most religions have beliefs about the existence of a God (or gods) who transcends sense experience. Ayer claimed that such beliefs are neither empirical nor analytic -- and hence are nonsensical.
"There is a God" is neither true nor false. So the question of the existence of God isn't a genuine intellectual issue. Believing in God may, however, express certain feelings about life -- and these may be important to the individual.