It is simply a nonsensical proposition. Thus, logical positivism indirectly asserted Hume's lawthe principle that is statements cannot justify ought statements, but are separated by an unbridgeable gap. A pamphlet jointly written by Otto Neurath -Hans Hahn - and Rudolf Carnap - brought together some of the major proponents of the movement and summarized the doctrines of the Vienna Circle at that time.
It grew from the discussions of the so-called "Vienna Circle" of Moritz Schlick - in the early 20th Century. Metaphysicsontologyas well as much of ethics failed this criterion, and so were found cognitively meaningless. But Ayer, adopting weak verification, does not consider them nonsense because they are in principle possible to observe to be true or false to a high probability.
So his proposition that the blue patch exists is verifiable.
Analysis of moral language should focus instead on its unique function as a guide to human behavior, what Stevenson called the "magnetism" of moral terms.