I thought B means that "It concludes against Ziegler's being sane, on the basis of evidence that there is a lack of evidence for Ziegler's being sane." lol

tbh, the assumptions required related to car theft knowledge is quite unfriendly for people who are unfamiliar to it

This chapter is so confusing, first, using A,B to in Lawgic is not representive enough. Also, the second lawgic is seemingly wrong, but it says it's valid.