Abolition is simply a sublime work (and that does not mean "I have sublime feelings" about it). What sets it above the typical critique of moral relativism is its understanding of the seat of morality: the affections, what Lewis calls "the chest." Following the Way is not simply a matter of recognizing universal categorical imperatives and following them. It is the affections that ultimately must be changed, be ordered, and that happens through education. That Gaius and Titius were making such an education impossible by removing their student-readers' hearts was what infuriated Lewis so much about their work.
Lewis greatly increases his credibility by not arguing too much in Abolition. For example, he does not set the Tao alongside total moral scepticism and attempt to prove the former superior on purely rational grounds. The Tao's demands are not conclusions of a rational argument. Hence, the attempt to construct a pared-down, convenient Tao, upon a ground like "instinct," must fail (a point Lewis demonstrates in the second lecture). Rather, the Tao's dictates are premises. Thus Lewis says "you must not hold a pistol to the head of the Tao." You can reject it or submit to it, but you cannot ask it to produce proofs of its own validity.
