Maybe there's some local custom about how written knowledge is supposed to be a record of all the things you shouldn't do, and from this, you can infer what you actually should do instead. Keltham genuinely has no idea if he's even supposed to believe all the claims the author puts in front of the book about his achievements, in a way that Keltham himself finds almost absolutely unconvincing; maybe it's this huge string of blatantly false advertisements, and it's actually signaling cleverness at crafting false advertisements, or... Keltham doesn't get Golarion at all, at this point. Is he supposed to believe the thing about storing up punishments to be inflicted at the end of the day in defiance of all behavioral shaping theory, and the implicit claim that students are so admiring of this teacher and desirous to learn his knowledge, that they stick around even after being hurt? Keltham is guessing this is just a status brag claim in a very alien format? Whatever; it should mostly fall under the rule of, for the moment, not believing any fact which a Drugs Author seems to be actually trying to make him believe.
Mostly, Keltham is interested in the discussion of the simplest spells, the meditations, the tips for common errors. How does a very basic spellcast actually work, if Keltham tries taking what the author says at face value, when it hopefully maybe looks like the author isn't being political and would be discussing something that ought to be politically nonvalent ordinary common knowledge.