All empirical propositions, even gravity, are theories only, and can never be proven, because of the inadequacy of the observing equipment. When Ayers gets to ethics, he is particularly merciless. The presence of an ethical symbol in a proposition adds nothing to its factual content. In adding that this action is wrong I am not making any further statement about it. I am simply evincing my moral disapproval of it.
Rules are norms, and norms have little to do with logic or truth.
Ayers makes me remember Professor Mothersill of Barnard College, whose ethics course I took around 1975. Presumably, Ayers did not go around robbing blind newsboys. It repudiates the gladiatorial theory of existence. Thus, according to Huxley, ethics combats nature. This is a crucial point, rarely overtly considered, for all modern political debate.